fedora core 6 1.2949 + vserver 2.2.0
[linux-2.6.git] / drivers / block / ub.c
index acea9f0..2098eff 100644 (file)
  * and is not licensed separately. See file COPYING for details.
  *
  * TODO (sorted by decreasing priority)
- *  -- Do resets with usb_device_reset (needs a thread context, use khubd)
  *  -- set readonly flag for CDs, set removable flag for CF readers
  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
- *  -- support pphaneuf's SDDR-75 with two LUNs (also broken capacity...)
- *  -- special case some senses, e.g. 3a/0 -> no media present, reduce retries
  *  -- verify the 13 conditions and do bulk resets
- *  -- normal pool of commands instead of cmdv[]?
- *  -- kill last_pipe and simply do two-state clearing on both pipes
- *  -- verify protocol (bulk) from USB descriptors (maybe...)
- *  -- highmem and sg
+ *  -- highmem
  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  *     for cache purists and esoteric architectures.
+ *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  *  -- prune comments, they are too volumnous
- *  -- Exterminate P3 printks
  *  -- Resove XXX's
- *  -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
+ *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/usb.h>
+#include <linux/usb_usual.h>
 #include <linux/blkdev.h>
-#include <linux/devfs_fs_kernel.h>
 #include <linux/timer.h>
 #include <scsi/scsi.h>
 
 #define DRV_NAME "ub"
-#define DEVFS_NAME DRV_NAME
 
 #define UB_MAJOR 180
 
 /*
- * Definitions which have to be scattered once we understand the layout better.
+ * The command state machine is the key model for understanding of this driver.
+ *
+ * The general rule is that all transitions are done towards the bottom
+ * of the diagram, thus preventing any loops.
+ *
+ * An exception to that is how the STAT state is handled. A counter allows it
+ * to be re-entered along the path marked with [C].
+ *
+ *       +--------+
+ *       ! INIT   !
+ *       +--------+
+ *           !
+ *        ub_scsi_cmd_start fails ->--------------------------------------\
+ *           !                                                            !
+ *           V                                                            !
+ *       +--------+                                                       !
+ *       ! CMD    !                                                       !
+ *       +--------+                                                       !
+ *           !                                            +--------+      !
+ *         was -EPIPE -->-------------------------------->! CLEAR  !      !
+ *           !                                            +--------+      !
+ *           !                                                !           !
+ *         was error -->------------------------------------- ! --------->\
+ *           !                                                !           !
+ *  /--<-- cmd->dir == NONE ?                                 !           !
+ *  !        !                                                !           !
+ *  !        V                                                !           !
+ *  !    +--------+                                           !           !
+ *  !    ! DATA   !                                           !           !
+ *  !    +--------+                                           !           !
+ *  !        !                           +---------+          !           !
+ *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
+ *  !        !                           +---------+          !           !
+ *  !        !                                !               !           !
+ *  !        !                              was error -->---- ! --------->\
+ *  !      was error -->--------------------- ! ------------- ! --------->\
+ *  !        !                                !               !           !
+ *  !        V                                !               !           !
+ *  \--->+--------+                           !               !           !
+ *       ! STAT   !<--------------------------/               !           !
+ *  /--->+--------+                                           !           !
+ *  !        !                                                !           !
+ * [C]     was -EPIPE -->-----------\                         !           !
+ *  !        !                      !                         !           !
+ *  +<---- len == 0                 !                         !           !
+ *  !        !                      !                         !           !
+ *  !      was error -->--------------------------------------!---------->\
+ *  !        !                      !                         !           !
+ *  +<---- bad CSW                  !                         !           !
+ *  +<---- bad tag                  !                         !           !
+ *  !        !                      V                         !           !
+ *  !        !                 +--------+                     !           !
+ *  !        !                 ! CLRRS  !                     !           !
+ *  !        !                 +--------+                     !           !
+ *  !        !                      !                         !           !
+ *  \------- ! --------------------[C]--------\               !           !
+ *           !                                !               !           !
+ *         cmd->error---\                +--------+           !           !
+ *           !          +--------------->! SENSE  !<----------/           !
+ *         STAT_FAIL----/                +--------+                       !
+ *           !                                !                           V
+ *           !                                V                      +--------+
+ *           \--------------------------------\--------------------->! DONE   !
+ *                                                                   +--------+
  */
 
-/* Transport (despite PR in the name) */
-#define US_PR_BULK     0x50            /* bulk only */
-
-/* Protocol */
-#define US_SC_SCSI     0x06            /* Transparent */
+/*
+ * This many LUNs per USB device.
+ * Every one of them takes a host, see UB_MAX_HOSTS.
+ */
+#define UB_MAX_LUNS   9
 
 /*
  */
-#define UB_MINORS_PER_MAJOR    8
+
+#define UB_PARTS_PER_LUN      8
 
 #define UB_MAX_CDB_SIZE      16                /* Corresponds to Bulk */
 
@@ -65,7 +122,7 @@ struct bulk_cb_wrap {
        u32     Tag;                    /* unique per command id */
        __le32  DataTransferLength;     /* size of data */
        u8      Flags;                  /* direction in bit 0 */
-       u8      Lun;                    /* LUN normally 0 */
+       u8      Lun;                    /* LUN */
        u8      Length;                 /* of of the CDB */
        u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 };
@@ -85,8 +142,6 @@ struct bulk_cs_wrap {
 
 #define US_BULK_CS_WRAP_LEN    13
 #define US_BULK_CS_SIGN                0x53425355      /* spells out 'USBS' */
-/* This is for Olympus Camedia digital cameras */
-#define US_BULK_CS_OLYMPUS_SIGN        0x55425355      /* spells out 'USBU' */
 #define US_BULK_STAT_OK                0
 #define US_BULK_STAT_FAIL      1
 #define US_BULK_STAT_PHASE     2
@@ -99,7 +154,7 @@ struct bulk_cs_wrap {
  */
 struct ub_dev;
 
-#define UB_MAX_REQ_SG  1
+#define UB_MAX_REQ_SG  9       /* cdrecord requires 32KB and maybe a header */
 #define UB_MAX_SECTORS 64
 
 /*
@@ -129,27 +184,16 @@ enum ub_scsi_cmd_state {
        UB_CMDST_CLR2STS,               /* Clearing before requesting status */
        UB_CMDST_STAT,                  /* Status phase */
        UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
+       UB_CMDST_CLRRS,                 /* Clearing before retrying status */
        UB_CMDST_SENSE,                 /* Sending Request Sense */
        UB_CMDST_DONE                   /* Final state */
 };
 
-static char *ub_scsi_cmd_stname[] = {
-       ".  ",
-       "Cmd",
-       "dat",
-       "c2s",
-       "sts",
-       "clr",
-       "Sen",
-       "fin"
-};
-
 struct ub_scsi_cmd {
        unsigned char cdb[UB_MAX_CDB_SIZE];
        unsigned char cdb_len;
 
        unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
-       unsigned char trace_index;
        enum ub_scsi_cmd_state state;
        unsigned int tag;
        struct ub_scsi_cmd *next;
@@ -160,18 +204,23 @@ struct ub_scsi_cmd {
 
        int stat_count;                 /* Retries getting status. */
 
-       /*
-        * We do not support transfers from highmem pages
-        * because the underlying USB framework does not do what we need.
-        */
-       char *data;                     /* Requested buffer */
        unsigned int len;               /* Requested length */
-       // struct scatterlist sgv[UB_MAX_REQ_SG];
+       unsigned int current_sg;
+       unsigned int nsg;               /* sgv[nsg] */
+       struct scatterlist sgv[UB_MAX_REQ_SG];
 
+       struct ub_lun *lun;
        void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
        void *back;
 };
 
+struct ub_request {
+       struct request *rq;
+       unsigned int current_try;
+       unsigned int nsg;               /* sgv[nsg] */
+       struct scatterlist sgv[UB_MAX_REQ_SG];
+};
+
 /*
  */
 struct ub_capacity {
@@ -180,28 +229,6 @@ struct ub_capacity {
        unsigned int bshift;            /* Shift between 512 and hard sects */
 };
 
-/*
- * The SCSI command tracing structure.
- */
-
-#define SCMD_ST_HIST_SZ   8
-#define SCMD_TRACE_SZ    63            /* Less than 4KB of 61-byte lines */
-
-struct ub_scsi_cmd_trace {
-       int hcur;
-       unsigned int tag;
-       unsigned int req_size, act_size;
-       unsigned char op;
-       unsigned char dir;
-       unsigned char key, asc, ascq;
-       char st_hst[SCMD_ST_HIST_SZ];   
-};
-
-struct ub_scsi_trace {
-       int cur;
-       struct ub_scsi_cmd_trace vec[SCMD_TRACE_SZ];
-};
-
 /*
  * This is a direct take-off from linux/include/completion.h
  * The difference is that I do not wait on this thing, just poll.
@@ -252,25 +279,49 @@ struct ub_scsi_cmd_queue {
 };
 
 /*
- * The UB device instance.
+ * The block device instance (one per LUN).
+ */
+struct ub_lun {
+       struct ub_dev *udev;
+       struct list_head link;
+       struct gendisk *disk;
+       int id;                         /* Host index */
+       int num;                        /* LUN number */
+       char name[16];
+
+       int changed;                    /* Media was changed */
+       int removable;
+       int readonly;
+
+       struct ub_request urq;
+
+       /* Use Ingo's mempool if or when we have more than one command. */
+       /*
+        * Currently we never need more than one command for the whole device.
+        * However, giving every LUN a command is a cheap and automatic way
+        * to enforce fairness between them.
+        */
+       int cmda[1];
+       struct ub_scsi_cmd cmdv[1];
+
+       struct ub_capacity capacity; 
+};
+
+/*
+ * The USB device instance.
  */
 struct ub_dev {
-       spinlock_t lock;
-       int id;                         /* Number among ub's */
+       spinlock_t *lock;
        atomic_t poison;                /* The USB device is disconnected */
        int openc;                      /* protected by ub_lock! */
                                        /* kref is too implicit for our taste */
+       int reset;                      /* Reset is running */
        unsigned int tagcnt;
-       int changed;                    /* Media was changed */
-       int removable;
-       int readonly;
-       int first_open;                 /* Kludge. See ub_bd_open. */
-       char name[8];
+       char name[12];
        struct usb_device *dev;
        struct usb_interface *intf;
 
-       struct ub_capacity capacity; 
-       struct gendisk *disk;
+       struct list_head luns;
 
        unsigned int send_bulk_pipe;    /* cached pipe values */
        unsigned int recv_bulk_pipe;
@@ -279,10 +330,6 @@ struct ub_dev {
 
        struct tasklet_struct tasklet;
 
-       /* XXX Use Ingo's mempool (once we have more than one) */
-       int cmda[1];
-       struct ub_scsi_cmd cmdv[1];
-
        struct ub_scsi_cmd_queue cmd_queue;
        struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
        unsigned char top_sense[UB_SENSE_SIZE];
@@ -291,46 +338,66 @@ struct ub_dev {
        struct urb work_urb;
        struct timer_list work_timer;
        int last_pipe;                  /* What might need clearing */
+       __le32 signature;               /* Learned signature */
        struct bulk_cb_wrap work_bcb;
        struct bulk_cs_wrap work_bcs;
        struct usb_ctrlrequest work_cr;
 
-       struct ub_scsi_trace tr;
+       struct work_struct reset_work;
+       wait_queue_head_t reset_wait;
+
+       int sg_stat[6];
 };
 
 /*
  */
-static int ub_bd_rq_fn_1(struct ub_dev *sc, struct request *rq);
-static int ub_cmd_build_block(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
-    struct request *rq);
-static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
-    struct request *rq);
+static void ub_cleanup(struct ub_dev *sc);
+static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
+static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_scsi_cmd *cmd, struct ub_request *urq);
+static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_scsi_cmd *cmd, struct ub_request *urq);
 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
-static void ub_end_rq(struct request *rq, int uptodate);
+static void ub_end_rq(struct request *rq, unsigned int status);
+static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_request *urq, struct ub_scsi_cmd *cmd);
 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
-static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);
+static void ub_urb_complete(struct urb *urb);
 static void ub_scsi_action(unsigned long _dev);
 static void ub_scsi_dispatch(struct ub_dev *sc);
 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
+static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
-static void __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
+static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
+static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
     int stalled_pipe);
 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
-static int ub_sync_tur(struct ub_dev *sc);
-static int ub_sync_read_cap(struct ub_dev *sc, struct ub_capacity *ret);
+static void ub_reset_enter(struct ub_dev *sc, int try);
+static void ub_reset_task(struct work_struct *work);
+static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
+static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_capacity *ret);
+static int ub_sync_reset(struct ub_dev *sc);
+static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
+static int ub_probe_lun(struct ub_dev *sc, int lnum);
 
 /*
  */
+#ifdef CONFIG_USB_LIBUSUAL
+
+#define ub_usb_ids  storage_usb_ids
+#else
+
 static struct usb_device_id ub_usb_ids[] = {
-       // { USB_DEVICE_VER(0x0781, 0x0002, 0x0009, 0x0009) },  /* SDDR-31 */
        { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
        { }
 };
 
 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
+#endif /* CONFIG_USB_LIBUSUAL */
 
 /*
  * Find me a way to identify "next free minor" for add_disk(),
@@ -341,118 +408,12 @@ MODULE_DEVICE_TABLE(usb, ub_usb_ids);
  */
 #define UB_MAX_HOSTS  26
 static char ub_hostv[UB_MAX_HOSTS];
-static DEFINE_SPINLOCK(ub_lock);       /* Locks globals and ->openc */
-
-/*
- * The SCSI command tracing procedures.
- */
-
-static void ub_cmdtr_new(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
-{
-       int n;
-       struct ub_scsi_cmd_trace *t;
-
-       if ((n = sc->tr.cur + 1) == SCMD_TRACE_SZ) n = 0;
-       t = &sc->tr.vec[n];
-
-       memset(t, 0, sizeof(struct ub_scsi_cmd_trace));
-       t->tag = cmd->tag;
-       t->op = cmd->cdb[0];
-       t->dir = cmd->dir;
-       t->req_size = cmd->len;
-       t->st_hst[0] = cmd->state;
-
-       sc->tr.cur = n;
-       cmd->trace_index = n;
-}
-
-static void ub_cmdtr_state(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
-{
-       int n;
-       struct ub_scsi_cmd_trace *t;
-
-       t = &sc->tr.vec[cmd->trace_index];
-       if (t->tag == cmd->tag) {
-               if ((n = t->hcur + 1) == SCMD_ST_HIST_SZ) n = 0;
-               t->st_hst[n] = cmd->state;
-               t->hcur = n;
-       }
-}
-
-static void ub_cmdtr_act_len(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
-{
-       struct ub_scsi_cmd_trace *t;
 
-       t = &sc->tr.vec[cmd->trace_index];
-       if (t->tag == cmd->tag)
-               t->act_size = cmd->act_len;
-}
+#define UB_QLOCK_NUM 5
+static spinlock_t ub_qlockv[UB_QLOCK_NUM];
+static int ub_qlock_next = 0;
 
-static void ub_cmdtr_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
-    unsigned char *sense)
-{
-       struct ub_scsi_cmd_trace *t;
-
-       t = &sc->tr.vec[cmd->trace_index];
-       if (t->tag == cmd->tag) {
-               t->key = sense[2] & 0x0F;
-               t->asc = sense[12];
-               t->ascq = sense[13];
-       }
-}
-
-static ssize_t ub_diag_show(struct device *dev, char *page)
-{
-       struct usb_interface *intf;
-       struct ub_dev *sc;
-       int cnt;
-       unsigned long flags;
-       int nc, nh;
-       int i, j;
-       struct ub_scsi_cmd_trace *t;
-
-       intf = to_usb_interface(dev);
-       sc = usb_get_intfdata(intf);
-       if (sc == NULL)
-               return 0;
-
-       cnt = 0;
-       spin_lock_irqsave(&sc->lock, flags);
-
-       cnt += sprintf(page + cnt,
-           "qlen %d qmax %d changed %d removable %d readonly %d\n",
-           sc->cmd_queue.qlen, sc->cmd_queue.qmax,
-           sc->changed, sc->removable, sc->readonly);
-
-       if ((nc = sc->tr.cur + 1) == SCMD_TRACE_SZ) nc = 0;
-       for (j = 0; j < SCMD_TRACE_SZ; j++) {
-               t = &sc->tr.vec[nc];
-
-               cnt += sprintf(page + cnt, "%08x %02x", t->tag, t->op);
-               if (t->op == REQUEST_SENSE) {
-                       cnt += sprintf(page + cnt, " [sense %x %02x %02x]",
-                                       t->key, t->asc, t->ascq);
-               } else {
-                       cnt += sprintf(page + cnt, " %c", UB_DIR_CHAR(t->dir));
-                       cnt += sprintf(page + cnt, " [%5d %5d]",
-                                       t->req_size, t->act_size);
-               }
-               if ((nh = t->hcur + 1) == SCMD_ST_HIST_SZ) nh = 0;
-               for (i = 0; i < SCMD_ST_HIST_SZ; i++) {
-                       cnt += sprintf(page + cnt, " %s",
-                                       ub_scsi_cmd_stname[(int)t->st_hst[nh]]);
-                       if (++nh == SCMD_ST_HIST_SZ) nh = 0;
-               }
-               cnt += sprintf(page + cnt, "\n");
-
-               if (++nc == SCMD_TRACE_SZ) nc = 0;
-       }
-
-       spin_unlock_irqrestore(&sc->lock, flags);
-       return cnt;
-}
-
-static DEVICE_ATTR(diag, S_IRUGO, ub_diag_show, NULL); /* N.B. World readable */
+static DEFINE_SPINLOCK(ub_lock);       /* Locks globals and ->openc */
 
 /*
  * The id allocator.
@@ -478,66 +439,128 @@ static int ub_id_get(void)
 
 static void ub_id_put(int id)
 {
+       unsigned long flags;
 
        if (id < 0 || id >= UB_MAX_HOSTS) {
                printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
                return;
        }
+
+       spin_lock_irqsave(&ub_lock, flags);
        if (ub_hostv[id] == 0) {
+               spin_unlock_irqrestore(&ub_lock, flags);
                printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
                return;
        }
        ub_hostv[id] = 0;
+       spin_unlock_irqrestore(&ub_lock, flags);
+}
+
+/*
+ * This is necessitated by the fact that blk_cleanup_queue does not
+ * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
+ * Since our blk_init_queue() passes a spinlock common with ub_dev,
+ * we have life time issues when ub_cleanup frees ub_dev.
+ */
+static spinlock_t *ub_next_lock(void)
+{
+       unsigned long flags;
+       spinlock_t *ret;
+
+       spin_lock_irqsave(&ub_lock, flags);
+       ret = &ub_qlockv[ub_qlock_next];
+       ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
+       spin_unlock_irqrestore(&ub_lock, flags);
+       return ret;
+}
+
+/*
+ * Downcount for deallocation. This rides on two assumptions:
+ *  - once something is poisoned, its refcount cannot grow
+ *  - opens cannot happen at this time (del_gendisk was done)
+ * If the above is true, we can drop the lock, which we need for
+ * blk_cleanup_queue(): the silly thing may attempt to sleep.
+ * [Actually, it never needs to sleep for us, but it calls might_sleep()]
+ */
+static void ub_put(struct ub_dev *sc)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&ub_lock, flags);
+       --sc->openc;
+       if (sc->openc == 0 && atomic_read(&sc->poison)) {
+               spin_unlock_irqrestore(&ub_lock, flags);
+               ub_cleanup(sc);
+       } else {
+               spin_unlock_irqrestore(&ub_lock, flags);
+       }
 }
 
 /*
  * Final cleanup and deallocation.
- * This must be called with ub_lock taken.
  */
 static void ub_cleanup(struct ub_dev *sc)
 {
+       struct list_head *p;
+       struct ub_lun *lun;
+       request_queue_t *q;
 
-       /*
-        * If we zero disk->private_data BEFORE put_disk, we have to check
-        * for NULL all over the place in open, release, check_media and
-        * revalidate, because the block level semaphore is well inside the
-        * put_disk. But we cannot zero after the call, because *disk is gone.
-        * The sd.c is blatantly racy in this area.
-        */
-       /* disk->private_data = NULL; */
-       put_disk(sc->disk);
-       sc->disk = NULL;
+       while (!list_empty(&sc->luns)) {
+               p = sc->luns.next;
+               lun = list_entry(p, struct ub_lun, link);
+               list_del(p);
+
+               /* I don't think queue can be NULL. But... Stolen from sx8.c */
+               if ((q = lun->disk->queue) != NULL)
+                       blk_cleanup_queue(q);
+               /*
+                * If we zero disk->private_data BEFORE put_disk, we have
+                * to check for NULL all over the place in open, release,
+                * check_media and revalidate, because the block level
+                * semaphore is well inside the put_disk.
+                * But we cannot zero after the call, because *disk is gone.
+                * The sd.c is blatantly racy in this area.
+                */
+               /* disk->private_data = NULL; */
+               put_disk(lun->disk);
+               lun->disk = NULL;
+
+               ub_id_put(lun->id);
+               kfree(lun);
+       }
 
-       ub_id_put(sc->id);
+       usb_set_intfdata(sc->intf, NULL);
+       usb_put_intf(sc->intf);
+       usb_put_dev(sc->dev);
        kfree(sc);
 }
 
 /*
  * The "command allocator".
  */
-static struct ub_scsi_cmd *ub_get_cmd(struct ub_dev *sc)
+static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 {
        struct ub_scsi_cmd *ret;
 
-       if (sc->cmda[0])
+       if (lun->cmda[0])
                return NULL;
-       ret = &sc->cmdv[0];
-       sc->cmda[0] = 1;
+       ret = &lun->cmdv[0];
+       lun->cmda[0] = 1;
        return ret;
 }
 
-static void ub_put_cmd(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 {
-       if (cmd != &sc->cmdv[0]) {
+       if (cmd != &lun->cmdv[0]) {
                printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
-                   sc->name, cmd);
+                   lun->name, cmd);
                return;
        }
-       if (!sc->cmda[0]) {
-               printk(KERN_WARNING "%s: releasing a free cmd\n", sc->name);
+       if (!lun->cmda[0]) {
+               printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
                return;
        }
-       sc->cmda[0] = 0;
+       lun->cmda[0] = 0;
 }
 
 /*
@@ -596,119 +619,103 @@ static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
  * The request function is our main entry point
  */
 
-static void ub_bd_rq_fn(request_queue_t *q)
+static void ub_request_fn(request_queue_t *q)
 {
-       struct ub_dev *sc = q->queuedata;
+       struct ub_lun *lun = q->queuedata;
        struct request *rq;
 
        while ((rq = elv_next_request(q)) != NULL) {
-               if (ub_bd_rq_fn_1(sc, rq) != 0) {
+               if (ub_request_fn_1(lun, rq) != 0) {
                        blk_stop_queue(q);
                        break;
                }
        }
 }
 
-static int ub_bd_rq_fn_1(struct ub_dev *sc, struct request *rq)
+static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 {
+       struct ub_dev *sc = lun->udev;
        struct ub_scsi_cmd *cmd;
-       int rc;
+       struct ub_request *urq;
+       int n_elem;
+
+       if (atomic_read(&sc->poison)) {
+               blkdev_dequeue_request(rq);
+               ub_end_rq(rq, DID_NO_CONNECT << 16);
+               return 0;
+       }
 
-       if (atomic_read(&sc->poison) || sc->changed) {
+       if (lun->changed && !blk_pc_request(rq)) {
                blkdev_dequeue_request(rq);
-               ub_end_rq(rq, 0);
+               ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
                return 0;
        }
 
-       if ((cmd = ub_get_cmd(sc)) == NULL)
+       if (lun->urq.rq != NULL)
+               return -1;
+       if ((cmd = ub_get_cmd(lun)) == NULL)
                return -1;
        memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 
        blkdev_dequeue_request(rq);
 
-       if (blk_pc_request(rq)) {
-               rc = ub_cmd_build_packet(sc, cmd, rq);
-       } else {
-               rc = ub_cmd_build_block(sc, cmd, rq);
+       urq = &lun->urq;
+       memset(urq, 0, sizeof(struct ub_request));
+       urq->rq = rq;
+
+       /*
+        * get scatterlist from block layer
+        */
+       n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
+       if (n_elem < 0) {
+               /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
+               printk(KERN_INFO "%s: failed request map (%d)\n",
+                   lun->name, n_elem);
+               goto drop;
        }
-       if (rc != 0) {
-               ub_put_cmd(sc, cmd);
-               ub_end_rq(rq, 0);
-               blk_start_queue(sc->disk->queue);
-               return 0;
+       if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
+               printk(KERN_WARNING "%s: request with %d segments\n",
+                   lun->name, n_elem);
+               goto drop;
        }
+       urq->nsg = n_elem;
+       sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 
+       if (blk_pc_request(rq)) {
+               ub_cmd_build_packet(sc, lun, cmd, urq);
+       } else {
+               ub_cmd_build_block(sc, lun, cmd, urq);
+       }
        cmd->state = UB_CMDST_INIT;
+       cmd->lun = lun;
        cmd->done = ub_rw_cmd_done;
-       cmd->back = rq;
+       cmd->back = urq;
 
        cmd->tag = sc->tagcnt++;
-       if ((rc = ub_submit_scsi(sc, cmd)) != 0) {
-               ub_put_cmd(sc, cmd);
-               ub_end_rq(rq, 0);
-               blk_start_queue(sc->disk->queue);
-               return 0;
-       }
+       if (ub_submit_scsi(sc, cmd) != 0)
+               goto drop;
+
+       return 0;
 
+drop:
+       ub_put_cmd(lun, cmd);
+       ub_end_rq(rq, DID_ERROR << 16);
        return 0;
 }
 
-static int ub_cmd_build_block(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
-    struct request *rq)
+static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_scsi_cmd *cmd, struct ub_request *urq)
 {
-       int ub_dir;
-#if 0 /* We use rq->buffer for now */
-       struct scatterlist *sg;
-       int n_elem;
-#endif
+       struct request *rq = urq->rq;
        unsigned int block, nblks;
 
        if (rq_data_dir(rq) == WRITE)
-               ub_dir = UB_DIR_WRITE;
+               cmd->dir = UB_DIR_WRITE;
        else
-               ub_dir = UB_DIR_READ;
+               cmd->dir = UB_DIR_READ;
 
-       /*
-        * get scatterlist from block layer
-        */
-#if 0 /* We use rq->buffer for now */
-       sg = &cmd->sgv[0];
-       n_elem = blk_rq_map_sg(q, rq, sg);
-       if (n_elem <= 0) {
-               ub_put_cmd(sc, cmd);
-               ub_end_rq(rq, 0);
-               blk_start_queue(q);
-               return 0;               /* request with no s/g entries? */
-       }
-
-       if (n_elem != 1) {              /* Paranoia */
-               printk(KERN_WARNING "%s: request with %d segments\n",
-                   sc->name, n_elem);
-               ub_put_cmd(sc, cmd);
-               ub_end_rq(rq, 0);
-               blk_start_queue(q);
-               return 0;
-       }
-#endif
-
-       /*
-        * XXX Unfortunately, this check does not work. It is quite possible
-        * to get bogus non-null rq->buffer if you allow sg by mistake.
-        */
-       if (rq->buffer == NULL) {
-               /*
-                * This must not happen if we set the queue right.
-                * The block level must create bounce buffers for us.
-                */
-               static int do_print = 1;
-               if (do_print) {
-                       printk(KERN_WARNING "%s: unmapped block request"
-                           " flags 0x%lx sectors %lu\n",
-                           sc->name, rq->flags, rq->nr_sectors);
-                       do_print = 0;
-               }
-               return -1;
-       }
+       cmd->nsg = urq->nsg;
+       memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 
        /*
         * build the command
@@ -716,10 +723,10 @@ static int ub_cmd_build_block(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
         * The call to blk_queue_hardsect_size() guarantees that request
         * is aligned, but it is given in terms of 512 byte units, always.
         */
-       block = rq->sector >> sc->capacity.bshift;
-       nblks = rq->nr_sectors >> sc->capacity.bshift;
+       block = rq->sector >> lun->capacity.bshift;
+       nblks = rq->nr_sectors >> lun->capacity.bshift;
 
-       cmd->cdb[0] = (ub_dir == UB_DIR_READ)? READ_10: WRITE_10;
+       cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
        /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
        cmd->cdb[2] = block >> 24;
        cmd->cdb[3] = block >> 16;
@@ -729,30 +736,13 @@ static int ub_cmd_build_block(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
        cmd->cdb[8] = nblks;
        cmd->cdb_len = 10;
 
-       cmd->dir = ub_dir;
-       cmd->data = rq->buffer;
        cmd->len = rq->nr_sectors * 512;
-
-       return 0;
 }
 
-static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
-    struct request *rq)
+static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_scsi_cmd *cmd, struct ub_request *urq)
 {
-
-       if (rq->data_len != 0 && rq->data == NULL) {
-               static int do_print = 1;
-               if (do_print) {
-                       printk(KERN_WARNING "%s: unmapped packet request"
-                           " flags 0x%lx length %d\n",
-                           sc->name, rq->flags, rq->data_len);
-                       do_print = 0;
-               }
-               return -1;
-       }
-
-       memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
-       cmd->cdb_len = rq->cmd_len;
+       struct request *rq = urq->rq;
 
        if (rq->data_len == 0) {
                cmd->dir = UB_DIR_NONE;
@@ -762,42 +752,107 @@ static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
                else
                        cmd->dir = UB_DIR_READ;
        }
-       cmd->data = rq->data;
-       cmd->len = rq->data_len;
 
-       return 0;
+       cmd->nsg = urq->nsg;
+       memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
+
+       memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
+       cmd->cdb_len = rq->cmd_len;
+
+       cmd->len = rq->data_len;
 }
 
 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 {
-       struct request *rq = cmd->back;
-       struct gendisk *disk = sc->disk;
-       request_queue_t *q = disk->queue;
-       int uptodate;
+       struct ub_lun *lun = cmd->lun;
+       struct ub_request *urq = cmd->back;
+       struct request *rq;
+       unsigned int scsi_status;
 
-       if (blk_pc_request(rq)) {
-               /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
-               memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
-               rq->sense_len = UB_SENSE_SIZE;
+       rq = urq->rq;
+
+       if (cmd->error == 0) {
+               if (blk_pc_request(rq)) {
+                       if (cmd->act_len >= rq->data_len)
+                               rq->data_len = 0;
+                       else
+                               rq->data_len -= cmd->act_len;
+               }
+               scsi_status = 0;
+       } else {
+               if (blk_pc_request(rq)) {
+                       /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
+                       memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
+                       rq->sense_len = UB_SENSE_SIZE;
+                       if (sc->top_sense[0] != 0)
+                               scsi_status = SAM_STAT_CHECK_CONDITION;
+                       else
+                               scsi_status = DID_ERROR << 16;
+               } else {
+                       if (cmd->error == -EIO) {
+                               if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
+                                       return;
+                       }
+                       scsi_status = SAM_STAT_CHECK_CONDITION;
+               }
        }
 
-       if (cmd->error == 0)
+       urq->rq = NULL;
+
+       ub_put_cmd(lun, cmd);
+       ub_end_rq(rq, scsi_status);
+       blk_start_queue(lun->disk->queue);
+}
+
+static void ub_end_rq(struct request *rq, unsigned int scsi_status)
+{
+       int uptodate;
+
+       if (scsi_status == 0) {
                uptodate = 1;
-       else
+       } else {
                uptodate = 0;
-
-       ub_put_cmd(sc, cmd);
-       ub_end_rq(rq, uptodate);
-       blk_start_queue(q);
+               rq->errors = scsi_status;
+       }
+       end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
+       end_that_request_last(rq, uptodate);
 }
 
-static void ub_end_rq(struct request *rq, int uptodate)
+static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_request *urq, struct ub_scsi_cmd *cmd)
 {
-       int rc;
 
-       rc = end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
-       // assert(rc == 0);
-       end_that_request_last(rq);
+       if (atomic_read(&sc->poison))
+               return -ENXIO;
+
+       ub_reset_enter(sc, urq->current_try);
+
+       if (urq->current_try >= 3)
+               return -EIO;
+       urq->current_try++;
+
+       /* Remove this if anyone complains of flooding. */
+       printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
+           "[sense %x %02x %02x] retry %d\n",
+           sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
+           cmd->key, cmd->asc, cmd->ascq, urq->current_try);
+
+       memset(cmd, 0, sizeof(struct ub_scsi_cmd));
+       ub_cmd_build_block(sc, lun, cmd, urq);
+
+       cmd->state = UB_CMDST_INIT;
+       cmd->lun = lun;
+       cmd->done = ub_rw_cmd_done;
+       cmd->back = urq;
+
+       cmd->tag = sc->tagcnt++;
+
+#if 0 /* Wasteful */
+       return ub_submit_scsi(sc, cmd);
+#else
+       ub_cmdq_add(sc, cmd);
+       return 0;
+#endif
 }
 
 /*
@@ -808,8 +863,6 @@ static void ub_end_rq(struct request *rq, int uptodate)
  * No exceptions.
  *
  * Host is assumed locked.
- *
- * XXX We only support Bulk for the moment.
  */
 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 {
@@ -855,7 +908,7 @@ static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
        bcb->Tag = cmd->tag;            /* Endianness is not important */
        bcb->DataTransferLength = cpu_to_le32(cmd->len);
        bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
-       bcb->Lun = 0;                   /* No multi-LUN yet */
+       bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
        bcb->Length = cmd->cdb_len;
 
        /* copy the command payload */
@@ -866,7 +919,6 @@ static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
        sc->last_pipe = sc->send_bulk_pipe;
        usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
            bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
-       sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;
 
        /* Fill what we shouldn't be filling, because usb-storage did so. */
        sc->work_urb.actual_length = 0;
@@ -875,7 +927,6 @@ static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 
        if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
                /* XXX Clear stalls */
-               printk("ub: cmd #%d start failed (%d)\n", cmd->tag, rc); /* P3 */
                ub_complete(&sc->work_done);
                return rc;
        }
@@ -884,7 +935,6 @@ static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
        add_timer(&sc->work_timer);
 
        cmd->state = UB_CMDST_CMD;
-       ub_cmdtr_state(sc, cmd);
        return 0;
 }
 
@@ -896,9 +946,10 @@ static void ub_urb_timeout(unsigned long arg)
        struct ub_dev *sc = (struct ub_dev *) arg;
        unsigned long flags;
 
-       spin_lock_irqsave(&sc->lock, flags);
-       usb_unlink_urb(&sc->work_urb);
-       spin_unlock_irqrestore(&sc->lock, flags);
+       spin_lock_irqsave(sc->lock, flags);
+       if (!ub_is_completed(&sc->work_done))
+               usb_unlink_urb(&sc->work_urb);
+       spin_unlock_irqrestore(sc->lock, flags);
 }
 
 /*
@@ -908,7 +959,7 @@ static void ub_urb_timeout(unsigned long arg)
  * the sc->lock taken) and from an interrupt (while we do NOT have
  * the sc->lock taken). Therefore, bounce this off to a tasklet.
  */
-static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
+static void ub_urb_complete(struct urb *urb)
 {
        struct ub_dev *sc = urb->context;
 
@@ -921,10 +972,9 @@ static void ub_scsi_action(unsigned long _dev)
        struct ub_dev *sc = (struct ub_dev *) _dev;
        unsigned long flags;
 
-       spin_lock_irqsave(&sc->lock, flags);
-       del_timer(&sc->work_timer);
+       spin_lock_irqsave(sc->lock, flags);
        ub_scsi_dispatch(sc);
-       spin_unlock_irqrestore(&sc->lock, flags);
+       spin_unlock_irqrestore(sc->lock, flags);
 }
 
 static void ub_scsi_dispatch(struct ub_dev *sc)
@@ -932,20 +982,19 @@ static void ub_scsi_dispatch(struct ub_dev *sc)
        struct ub_scsi_cmd *cmd;
        int rc;
 
-       while ((cmd = ub_cmdq_peek(sc)) != NULL) {
+       while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
                if (cmd->state == UB_CMDST_DONE) {
                        ub_cmdq_pop(sc);
                        (*cmd->done)(sc, cmd);
                } else if (cmd->state == UB_CMDST_INIT) {
-                       ub_cmdtr_new(sc, cmd);
                        if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
                                break;
                        cmd->error = rc;
                        cmd->state = UB_CMDST_DONE;
-                       ub_cmdtr_state(sc, cmd);
                } else {
                        if (!ub_is_completed(&sc->work_done))
                                break;
+                       del_timer(&sc->work_timer);
                        ub_scsi_urb_compl(sc, cmd);
                }
        }
@@ -955,12 +1004,12 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 {
        struct urb *urb = &sc->work_urb;
        struct bulk_cs_wrap *bcs;
-       int pipe;
+       int len;
        int rc;
 
        if (atomic_read(&sc->poison)) {
-               /* A little too simplistic, I feel... */
-               goto Bad_End;
+               ub_state_done(sc, cmd, -ENODEV);
+               return;
        }
 
        if (cmd->state == UB_CMDST_CLEAR) {
@@ -968,11 +1017,9 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
                        /*
                         * STALL while clearning STALL.
                         * The control pipe clears itself - nothing to do.
-                        * XXX Might try to reset the device here and retry.
                         */
-                       printk(KERN_NOTICE "%s: "
-                           "stall on control pipe for device %u\n",
-                           sc->name, sc->dev->devnum);
+                       printk(KERN_NOTICE "%s: stall on control pipe\n",
+                           sc->name);
                        goto Bad_End;
                }
 
@@ -988,14 +1035,8 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 
        } else if (cmd->state == UB_CMDST_CLR2STS) {
                if (urb->status == -EPIPE) {
-                       /*
-                        * STALL while clearning STALL.
-                        * The control pipe clears itself - nothing to do.
-                        * XXX Might try to reset the device here and retry.
-                        */
-                       printk(KERN_NOTICE "%s: "
-                           "stall on control pipe for device %u\n",
-                           sc->name, sc->dev->devnum);
+                       printk(KERN_NOTICE "%s: stall on control pipe\n",
+                           sc->name);
                        goto Bad_End;
                }
 
@@ -1009,83 +1050,74 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 
                ub_state_stat(sc, cmd);
 
-       } else if (cmd->state == UB_CMDST_CMD) {
+       } else if (cmd->state == UB_CMDST_CLRRS) {
                if (urb->status == -EPIPE) {
+                       printk(KERN_NOTICE "%s: stall on control pipe\n",
+                           sc->name);
+                       goto Bad_End;
+               }
+
+               /*
+                * We ignore the result for the halt clear.
+                */
+
+               /* reset the endpoint toggle */
+               usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
+                       usb_pipeout(sc->last_pipe), 0);
+
+               ub_state_stat_counted(sc, cmd);
+
+       } else if (cmd->state == UB_CMDST_CMD) {
+               switch (urb->status) {
+               case 0:
+                       break;
+               case -EOVERFLOW:
+                       goto Bad_End;
+               case -EPIPE:
                        rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
                        if (rc != 0) {
                                printk(KERN_NOTICE "%s: "
-                                   "unable to submit clear for device %u"
-                                   " (code %d)\n",
-                                   sc->name, sc->dev->devnum, rc);
+                                   "unable to submit clear (%d)\n",
+                                   sc->name, rc);
                                /*
                                 * This is typically ENOMEM or some other such shit.
                                 * Retrying is pointless. Just do Bad End on it...
                                 */
-                               goto Bad_End;
+                               ub_state_done(sc, cmd, rc);
+                               return;
                        }
                        cmd->state = UB_CMDST_CLEAR;
-                       ub_cmdtr_state(sc, cmd);
                        return;
-               }
-               if (urb->status != 0) {
-                       printk("ub: cmd #%d cmd status (%d)\n", cmd->tag, urb->status); /* P3 */
+               case -ESHUTDOWN:        /* unplug */
+               case -EILSEQ:           /* unplug timeout on uhci */
+                       ub_state_done(sc, cmd, -ENODEV);
+                       return;
+               default:
                        goto Bad_End;
                }
                if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
-                       printk("ub: cmd #%d xferred %d\n", cmd->tag, urb->actual_length); /* P3 */
-                       /* XXX Must do reset here to unconfuse the device */
                        goto Bad_End;
                }
 
-               if (cmd->dir == UB_DIR_NONE) {
+               if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
                        ub_state_stat(sc, cmd);
                        return;
                }
 
-               UB_INIT_COMPLETION(sc->work_done);
-
-               if (cmd->dir == UB_DIR_READ)
-                       pipe = sc->recv_bulk_pipe;
-               else
-                       pipe = sc->send_bulk_pipe;
-               sc->last_pipe = pipe;
-               usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
-                   cmd->data, cmd->len, ub_urb_complete, sc);
-               sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;
-               sc->work_urb.actual_length = 0;
-               sc->work_urb.error_count = 0;
-               sc->work_urb.status = 0;
-
-               if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
-                       /* XXX Clear stalls */
-                       printk("ub: data #%d submit failed (%d)\n", cmd->tag, rc); /* P3 */
-                       ub_complete(&sc->work_done);
-                       ub_state_done(sc, cmd, rc);
-                       return;
-               }
-
-               sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
-               add_timer(&sc->work_timer);
-
-               cmd->state = UB_CMDST_DATA;
-               ub_cmdtr_state(sc, cmd);
+               // udelay(125);         // usb-storage has this
+               ub_data_start(sc, cmd);
 
        } else if (cmd->state == UB_CMDST_DATA) {
                if (urb->status == -EPIPE) {
                        rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
                        if (rc != 0) {
                                printk(KERN_NOTICE "%s: "
-                                   "unable to submit clear for device %u"
-                                   " (code %d)\n",
-                                   sc->name, sc->dev->devnum, rc);
-                               /*
-                                * This is typically ENOMEM or some other such shit.
-                                * Retrying is pointless. Just do Bad End on it...
-                                */
-                               goto Bad_End;
+                                   "unable to submit clear (%d)\n",
+                                   sc->name, rc);
+                               ub_state_done(sc, cmd, rc);
+                               return;
                        }
                        cmd->state = UB_CMDST_CLR2STS;
-                       ub_cmdtr_state(sc, cmd);
                        return;
                }
                if (urb->status == -EOVERFLOW) {
@@ -1093,14 +1125,54 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
                         * A babble? Failure, but we must transfer CSW now.
                         */
                        cmd->error = -EOVERFLOW;        /* A cheap trick... */
+                       ub_state_stat(sc, cmd);
+                       return;
+               }
+
+               if (cmd->dir == UB_DIR_WRITE) {
+                       /*
+                        * Do not continue writes in case of a failure.
+                        * Doing so would cause sectors to be mixed up,
+                        * which is worse than sectors lost.
+                        *
+                        * We must try to read the CSW, or many devices
+                        * get confused.
+                        */
+                       len = urb->actual_length;
+                       if (urb->status != 0 ||
+                           len != cmd->sgv[cmd->current_sg].length) {
+                               cmd->act_len += len;
+
+                               cmd->error = -EIO;
+                               ub_state_stat(sc, cmd);
+                               return;
+                       }
+
                } else {
+                       /*
+                        * If an error occurs on read, we record it, and
+                        * continue to fetch data in order to avoid bubble.
+                        *
+                        * As a small shortcut, we stop if we detect that
+                        * a CSW mixed into data.
+                        */
                        if (urb->status != 0)
-                               goto Bad_End;
+                               cmd->error = -EIO;
+
+                       len = urb->actual_length;
+                       if (urb->status != 0 ||
+                           len != cmd->sgv[cmd->current_sg].length) {
+                               if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
+                                       goto Bad_End;
+                       }
                }
 
-               cmd->act_len = urb->actual_length;
-               ub_cmdtr_act_len(sc, cmd);
+               cmd->act_len += urb->actual_length;
 
+               if (++cmd->current_sg < cmd->nsg) {
+                       ub_data_start(sc, cmd);
+                       return;
+               }
                ub_state_stat(sc, cmd);
 
        } else if (cmd->state == UB_CMDST_STAT) {
@@ -1108,62 +1180,55 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
                        rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
                        if (rc != 0) {
                                printk(KERN_NOTICE "%s: "
-                                   "unable to submit clear for device %u"
-                                   " (code %d)\n",
-                                   sc->name, sc->dev->devnum, rc);
-                               /*
-                                * This is typically ENOMEM or some other such shit.
-                                * Retrying is pointless. Just do Bad End on it...
-                                */
-                               goto Bad_End;
+                                   "unable to submit clear (%d)\n",
+                                   sc->name, rc);
+                               ub_state_done(sc, cmd, rc);
+                               return;
                        }
-                       cmd->state = UB_CMDST_CLEAR;
-                       ub_cmdtr_state(sc, cmd);
+
+                       /*
+                        * Having a stall when getting CSW is an error, so
+                        * make sure uppper levels are not oblivious to it.
+                        */
+                       cmd->error = -EIO;              /* A cheap trick... */
+
+                       cmd->state = UB_CMDST_CLRRS;
                        return;
                }
+
+               /* Catch everything, including -EOVERFLOW and other nasties. */
                if (urb->status != 0)
                        goto Bad_End;
 
                if (urb->actual_length == 0) {
-                       /*
-                        * Some broken devices add unnecessary zero-length
-                        * packets to the end of their data transfers.
-                        * Such packets show up as 0-length CSWs. If we
-                        * encounter such a thing, try to read the CSW again.
-                        */
-                       if (++cmd->stat_count >= 4) {
-                               printk(KERN_NOTICE "%s: "
-                                   "unable to get CSW on device %u\n",
-                                   sc->name, sc->dev->devnum);
-                               goto Bad_End;
-                       }
-                       __ub_state_stat(sc, cmd);
+                       ub_state_stat_counted(sc, cmd);
                        return;
                }
 
                /*
                 * Check the returned Bulk protocol status.
+                * The status block has to be validated first.
                 */
 
                bcs = &sc->work_bcs;
-               rc = le32_to_cpu(bcs->Residue);
-               if (rc != cmd->len - cmd->act_len) {
+
+               if (sc->signature == cpu_to_le32(0)) {
                        /*
-                        * It is all right to transfer less, the caller has
-                        * to check. But it's not all right if the device
-                        * counts disagree with our counts.
+                        * This is the first reply, so do not perform the check.
+                        * Instead, remember the signature the device uses
+                        * for future checks. But do not allow a nul.
                         */
-                       /* P3 */ printk("%s: resid %d len %d act %d\n",
-                           sc->name, rc, cmd->len, cmd->act_len);
-                       goto Bad_End;
-               }
-
-#if 0
-               if (bcs->Signature != cpu_to_le32(US_BULK_CS_SIGN) &&
-                   bcs->Signature != cpu_to_le32(US_BULK_CS_OLYMPUS_SIGN)) {
-                       /* Windows ignores signatures, so do we. */
+                       sc->signature = bcs->Signature;
+                       if (sc->signature == cpu_to_le32(0)) {
+                               ub_state_stat_counted(sc, cmd);
+                               return;
+                       }
+               } else {
+                       if (bcs->Signature != sc->signature) {
+                               ub_state_stat_counted(sc, cmd);
+                               return;
+                       }
                }
-#endif
 
                if (bcs->Tag != cmd->tag) {
                        /*
@@ -1173,18 +1238,20 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
                         * commands and reply at commands we timed out before.
                         * Without flushing these replies we loop forever.
                         */
-                       if (++cmd->stat_count >= 4) {
-                               printk(KERN_NOTICE "%s: "
-                                   "tag mismatch orig 0x%x reply 0x%x "
-                                   "on device %u\n",
-                                   sc->name, cmd->tag, bcs->Tag,
-                                   sc->dev->devnum);
-                               goto Bad_End;
-                       }
-                       __ub_state_stat(sc, cmd);
+                       ub_state_stat_counted(sc, cmd);
                        return;
                }
 
+               len = le32_to_cpu(bcs->Residue);
+               if (len != cmd->len - cmd->act_len) {
+                       /*
+                        * It is all right to transfer less, the caller has
+                        * to check. But it's not all right if the device
+                        * counts disagree with our counts.
+                        */
+                       goto Bad_End;
+               }
+
                switch (bcs->Status) {
                case US_BULK_STAT_OK:
                        break;
@@ -1192,34 +1259,74 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
                        ub_state_sense(sc, cmd);
                        return;
                case US_BULK_STAT_PHASE:
-                       /* XXX We must reset the transport here */
-                       /* P3 */ printk("%s: status PHASE\n", sc->name);
                        goto Bad_End;
                default:
                        printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
                            sc->name, bcs->Status);
-                       goto Bad_End;
+                       ub_state_done(sc, cmd, -EINVAL);
+                       return;
                }
 
                /* Not zeroing error to preserve a babble indicator */
+               if (cmd->error != 0) {
+                       ub_state_sense(sc, cmd);
+                       return;
+               }
                cmd->state = UB_CMDST_DONE;
-               ub_cmdtr_state(sc, cmd);
                ub_cmdq_pop(sc);
                (*cmd->done)(sc, cmd);
 
        } else if (cmd->state == UB_CMDST_SENSE) {
                ub_state_done(sc, cmd, -EIO);
 
-       } else {
-               printk(KERN_WARNING "%s: "
-                   "wrong command state %d on device %u\n",
-                   sc->name, cmd->state, sc->dev->devnum);
-               goto Bad_End;
+       } else {
+               printk(KERN_WARNING "%s: "
+                   "wrong command state %d\n",
+                   sc->name, cmd->state);
+               ub_state_done(sc, cmd, -EINVAL);
+               return;
+       }
+       return;
+
+Bad_End: /* Little Excel is dead */
+       ub_state_done(sc, cmd, -EIO);
+}
+
+/*
+ * Factorization helper for the command state machine:
+ * Initiate a data segment transfer.
+ */
+static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+       struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
+       int pipe;
+       int rc;
+
+       UB_INIT_COMPLETION(sc->work_done);
+
+       if (cmd->dir == UB_DIR_READ)
+               pipe = sc->recv_bulk_pipe;
+       else
+               pipe = sc->send_bulk_pipe;
+       sc->last_pipe = pipe;
+       usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
+           page_address(sg->page) + sg->offset, sg->length,
+           ub_urb_complete, sc);
+       sc->work_urb.actual_length = 0;
+       sc->work_urb.error_count = 0;
+       sc->work_urb.status = 0;
+
+       if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
+               /* XXX Clear stalls */
+               ub_complete(&sc->work_done);
+               ub_state_done(sc, cmd, rc);
+               return;
        }
-       return;
 
-Bad_End: /* Little Excel is dead */
-       ub_state_done(sc, cmd, -EIO);
+       sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
+       add_timer(&sc->work_timer);
+
+       cmd->state = UB_CMDST_DATA;
 }
 
 /*
@@ -1231,7 +1338,6 @@ static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
 
        cmd->error = rc;
        cmd->state = UB_CMDST_DONE;
-       ub_cmdtr_state(sc, cmd);
        ub_cmdq_pop(sc);
        (*cmd->done)(sc, cmd);
 }
@@ -1240,7 +1346,7 @@ static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
  * Factorization helper for the command state machine:
  * Submit a CSW read.
  */
-static void __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 {
        int rc;
 
@@ -1249,21 +1355,20 @@ static void __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
        sc->last_pipe = sc->recv_bulk_pipe;
        usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
            &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
-       sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;
        sc->work_urb.actual_length = 0;
        sc->work_urb.error_count = 0;
        sc->work_urb.status = 0;
 
        if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
                /* XXX Clear stalls */
-               printk("%s: CSW #%d submit failed (%d)\n", sc->name, cmd->tag, rc); /* P3 */
                ub_complete(&sc->work_done);
                ub_state_done(sc, cmd, rc);
-               return;
+               return -1;
        }
 
        sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
        add_timer(&sc->work_timer);
+       return 0;
 }
 
 /*
@@ -1272,11 +1377,30 @@ static void __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
  */
 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 {
-       __ub_state_stat(sc, cmd);
+
+       if (__ub_state_stat(sc, cmd) != 0)
+               return;
 
        cmd->stat_count = 0;
        cmd->state = UB_CMDST_STAT;
-       ub_cmdtr_state(sc, cmd);
+}
+
+/*
+ * Factorization helper for the command state machine:
+ * Submit a CSW read and go to STAT state with counter (along [C] path).
+ */
+static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+
+       if (++cmd->stat_count >= 4) {
+               ub_state_sense(sc, cmd);
+               return;
+       }
+
+       if (__ub_state_stat(sc, cmd) != 0)
+               return;
+
+       cmd->state = UB_CMDST_STAT;
 }
 
 /*
@@ -1286,6 +1410,7 @@ static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 {
        struct ub_scsi_cmd *scmd;
+       struct scatterlist *sg;
        int rc;
 
        if (cmd->cdb[0] == REQUEST_SENSE) {
@@ -1294,20 +1419,25 @@ static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
        }
 
        scmd = &sc->top_rqs_cmd;
+       memset(scmd, 0, sizeof(struct ub_scsi_cmd));
        scmd->cdb[0] = REQUEST_SENSE;
        scmd->cdb[4] = UB_SENSE_SIZE;
        scmd->cdb_len = 6;
        scmd->dir = UB_DIR_READ;
        scmd->state = UB_CMDST_INIT;
-       scmd->data = sc->top_sense;
+       scmd->nsg = 1;
+       sg = &scmd->sgv[0];
+       sg->page = virt_to_page(sc->top_sense);
+       sg->offset = (unsigned long)sc->top_sense & (PAGE_SIZE-1);
+       sg->length = UB_SENSE_SIZE;
        scmd->len = UB_SENSE_SIZE;
+       scmd->lun = cmd->lun;
        scmd->done = ub_top_sense_done;
        scmd->back = cmd;
 
        scmd->tag = sc->tagcnt++;
 
        cmd->state = UB_CMDST_SENSE;
-       ub_cmdtr_state(sc, cmd);
 
        ub_cmdq_insert(sc, scmd);
        return;
@@ -1342,7 +1472,6 @@ static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 
        usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
            (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
-       sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;
        sc->work_urb.actual_length = 0;
        sc->work_urb.error_count = 0;
        sc->work_urb.status = 0;
@@ -1361,14 +1490,9 @@ static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
  */
 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
 {
-       unsigned char *sense = scmd->data;
+       unsigned char *sense = sc->top_sense;
        struct ub_scsi_cmd *cmd;
 
-       /*
-        * Ignoring scmd->act_len, because the buffer was pre-zeroed.
-        */
-       ub_cmdtr_sense(sc, scmd, sense);
-
        /*
         * Find the command which triggered the unit attention or a check,
         * save the sense into it, and advance its state machine.
@@ -1379,17 +1503,20 @@ static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
        }
        if (cmd != scmd->back) {
                printk(KERN_WARNING "%s: "
-                   "sense done for wrong command 0x%x on device %u\n",
-                   sc->name, cmd->tag, sc->dev->devnum);
+                   "sense done for wrong command 0x%x\n",
+                   sc->name, cmd->tag);
                return;
        }
        if (cmd->state != UB_CMDST_SENSE) {
                printk(KERN_WARNING "%s: "
-                   "sense done with bad cmd state %d on device %u\n",
-                   sc->name, cmd->state, sc->dev->devnum);
+                   "sense done with bad cmd state %d\n",
+                   sc->name, cmd->state);
                return;
        }
 
+       /*
+        * Ignoring scmd->act_len, because the buffer was pre-zeroed.
+        */
        cmd->key = sense[2] & 0x0F;
        cmd->asc = sense[12];
        cmd->ascq = sense[13];
@@ -1397,68 +1524,124 @@ static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
        ub_scsi_urb_compl(sc, cmd);
 }
 
-#if 0
-/* Determine what the maximum LUN supported is */
-int usb_stor_Bulk_max_lun(struct us_data *us)
+/*
+ * Reset management
+ * XXX Move usb_reset_device to khubd. Hogging kevent is not a good thing.
+ * XXX Make usb_sync_reset asynchronous.
+ */
+
+static void ub_reset_enter(struct ub_dev *sc, int try)
 {
-       int result;
-
-       /* issue the command */
-       result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
-                                US_BULK_GET_MAX_LUN, 
-                                USB_DIR_IN | USB_TYPE_CLASS | 
-                                USB_RECIP_INTERFACE,
-                                0, us->ifnum, us->iobuf, 1, HZ);
-
-       /* 
-        * Some devices (i.e. Iomega Zip100) need this -- apparently
-        * the bulk pipes get STALLed when the GetMaxLUN request is
-        * processed.   This is, in theory, harmless to all other devices
-        * (regardless of if they stall or not).
-        */
-       if (result < 0) {
-               usb_stor_clear_halt(us, us->recv_bulk_pipe);
-               usb_stor_clear_halt(us, us->send_bulk_pipe);
+
+       if (sc->reset) {
+               /* This happens often on multi-LUN devices. */
+               return;
        }
+       sc->reset = try + 1;
 
-       US_DEBUGP("GetMaxLUN command result is %d, data is %d\n", 
-                 result, us->iobuf[0]);
+#if 0 /* Not needed because the disconnect waits for us. */
+       unsigned long flags;
+       spin_lock_irqsave(&ub_lock, flags);
+       sc->openc++;
+       spin_unlock_irqrestore(&ub_lock, flags);
+#endif
 
-       /* if we have a successful request, return the result */
-       if (result == 1)
-               return us->iobuf[0];
+#if 0 /* We let them stop themselves. */
+       struct list_head *p;
+       struct ub_lun *lun;
+       list_for_each(p, &sc->luns) {
+               lun = list_entry(p, struct ub_lun, link);
+               blk_stop_queue(lun->disk->queue);
+       }
+#endif
 
-       /* return the default -- no LUNs */
-       return 0;
+       schedule_work(&sc->reset_work);
+}
+
+static void ub_reset_task(struct work_struct *work)
+{
+       struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
+       unsigned long flags;
+       struct list_head *p;
+       struct ub_lun *lun;
+       int lkr, rc;
+
+       if (!sc->reset) {
+               printk(KERN_WARNING "%s: Running reset unrequested\n",
+                   sc->name);
+               return;
+       }
+
+       if (atomic_read(&sc->poison)) {
+               ;
+       } else if ((sc->reset & 1) == 0) {
+               ub_sync_reset(sc);
+               msleep(700);    /* usb-storage sleeps 6s (!) */
+               ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
+               ub_probe_clear_stall(sc, sc->send_bulk_pipe);
+       } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
+               ;
+       } else {
+               if ((lkr = usb_lock_device_for_reset(sc->dev, sc->intf)) < 0) {
+                       printk(KERN_NOTICE
+                           "%s: usb_lock_device_for_reset failed (%d)\n",
+                           sc->name, lkr);
+               } else {
+                       rc = usb_reset_device(sc->dev);
+                       if (rc < 0) {
+                               printk(KERN_NOTICE "%s: "
+                                   "usb_lock_device_for_reset failed (%d)\n",
+                                   sc->name, rc);
+                       }
+
+                       if (lkr)
+                               usb_unlock_device(sc->dev);
+               }
+       }
+
+       /*
+        * In theory, no commands can be running while reset is active,
+        * so nobody can ask for another reset, and so we do not need any
+        * queues of resets or anything. We do need a spinlock though,
+        * to interact with block layer.
+        */
+       spin_lock_irqsave(sc->lock, flags);
+       sc->reset = 0;
+       tasklet_schedule(&sc->tasklet);
+       list_for_each(p, &sc->luns) {
+               lun = list_entry(p, struct ub_lun, link);
+               blk_start_queue(lun->disk->queue);
+       }
+       wake_up(&sc->reset_wait);
+       spin_unlock_irqrestore(sc->lock, flags);
 }
-#endif
 
 /*
  * This is called from a process context.
  */
-static void ub_revalidate(struct ub_dev *sc)
+static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
 {
 
-       sc->readonly = 0;       /* XXX Query this from the device */
+       lun->readonly = 0;      /* XXX Query this from the device */
 
-       sc->capacity.nsec = 0;
-       sc->capacity.bsize = 512;
-       sc->capacity.bshift = 0;
+       lun->capacity.nsec = 0;
+       lun->capacity.bsize = 512;
+       lun->capacity.bshift = 0;
 
-       if (ub_sync_tur(sc) != 0)
+       if (ub_sync_tur(sc, lun) != 0)
                return;                 /* Not ready */
-       sc->changed = 0;
+       lun->changed = 0;
 
-       if (ub_sync_read_cap(sc, &sc->capacity) != 0) {
+       if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
                /*
                 * The retry here means something is wrong, either with the
                 * device, with the transport, or with our code.
                 * We keep this because sd.c has retries for capacity.
                 */
-               if (ub_sync_read_cap(sc, &sc->capacity) != 0) {
-                       sc->capacity.nsec = 0;
-                       sc->capacity.bsize = 512;
-                       sc->capacity.bshift = 0;
+               if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
+                       lun->capacity.nsec = 0;
+                       lun->capacity.bsize = 512;
+                       lun->capacity.bshift = 0;
                }
        }
 }
@@ -1471,12 +1654,11 @@ static void ub_revalidate(struct ub_dev *sc)
 static int ub_bd_open(struct inode *inode, struct file *filp)
 {
        struct gendisk *disk = inode->i_bdev->bd_disk;
-       struct ub_dev *sc;
+       struct ub_lun *lun = disk->private_data;
+       struct ub_dev *sc = lun->udev;
        unsigned long flags;
        int rc;
 
-       if ((sc = disk->private_data) == NULL)
-               return -ENXIO;
        spin_lock_irqsave(&ub_lock, flags);
        if (atomic_read(&sc->poison)) {
                spin_unlock_irqrestore(&ub_lock, flags);
@@ -1485,27 +1667,7 @@ static int ub_bd_open(struct inode *inode, struct file *filp)
        sc->openc++;
        spin_unlock_irqrestore(&ub_lock, flags);
 
-       /*
-        * This is a workaround for a specific problem in our block layer.
-        * In 2.6.9, register_disk duplicates the code from rescan_partitions.
-        * However, if we do add_disk with a device which persistently reports
-        * a changed media, add_disk calls register_disk, which does do_open,
-        * which will call rescan_paritions for changed media. After that,
-        * register_disk attempts to do it all again and causes double kobject
-        * registration and a eventually an oops on module removal.
-        *
-        * The bottom line is, Al Viro says that we should not allow
-        * bdev->bd_invalidated to be set when doing add_disk no matter what.
-        */
-       if (sc->first_open) {
-               if (sc->changed) {
-                       sc->first_open = 0;
-                       rc = -ENOMEDIUM;
-                       goto err_open;
-               }
-       }
-
-       if (sc->removable || sc->readonly)
+       if (lun->removable || lun->readonly)
                check_disk_change(inode->i_bdev);
 
        /*
@@ -1513,12 +1675,12 @@ static int ub_bd_open(struct inode *inode, struct file *filp)
         * under some pretty murky conditions (a failure of READ CAPACITY).
         * We may need it one day.
         */
-       if (sc->removable && sc->changed && !(filp->f_flags & O_NDELAY)) {
+       if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
                rc = -ENOMEDIUM;
                goto err_open;
        }
 
-       if (sc->readonly && (filp->f_mode & FMODE_WRITE)) {
+       if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
                rc = -EROFS;
                goto err_open;
        }
@@ -1526,11 +1688,7 @@ static int ub_bd_open(struct inode *inode, struct file *filp)
        return 0;
 
 err_open:
-       spin_lock_irqsave(&ub_lock, flags);
-       --sc->openc;
-       if (sc->openc == 0 && atomic_read(&sc->poison))
-               ub_cleanup(sc);
-       spin_unlock_irqrestore(&ub_lock, flags);
+       ub_put(sc);
        return rc;
 }
 
@@ -1539,16 +1697,10 @@ err_open:
 static int ub_bd_release(struct inode *inode, struct file *filp)
 {
        struct gendisk *disk = inode->i_bdev->bd_disk;
-       struct ub_dev *sc = disk->private_data;
-       unsigned long flags;
+       struct ub_lun *lun = disk->private_data;
+       struct ub_dev *sc = lun->udev;
 
-       spin_lock_irqsave(&ub_lock, flags);
-       --sc->openc;
-       if (sc->openc == 0)
-               sc->first_open = 0;
-       if (sc->openc == 0 && atomic_read(&sc->poison))
-               ub_cleanup(sc);
-       spin_unlock_irqrestore(&ub_lock, flags);
+       ub_put(sc);
        return 0;
 }
 
@@ -1576,20 +1728,14 @@ static int ub_bd_ioctl(struct inode *inode, struct file *filp,
  */
 static int ub_bd_revalidate(struct gendisk *disk)
 {
-       struct ub_dev *sc = disk->private_data;
-
-       ub_revalidate(sc);
-       /* This is pretty much a long term P3 */
-       if (!atomic_read(&sc->poison)) {                /* Cover sc->dev */
-               printk(KERN_INFO "%s: device %u capacity nsec %ld bsize %u\n",
-                   sc->name, sc->dev->devnum,
-                   sc->capacity.nsec, sc->capacity.bsize);
-       }
+       struct ub_lun *lun = disk->private_data;
+
+       ub_revalidate(lun->udev, lun);
 
        /* XXX Support sector size switching like in sr.c */
-       blk_queue_hardsect_size(disk->queue, sc->capacity.bsize);
-       set_capacity(disk, sc->capacity.nsec);
-       // set_disk_ro(sdkp->disk, sc->readonly);
+       blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
+       set_capacity(disk, lun->capacity.nsec);
+       // set_disk_ro(sdkp->disk, lun->readonly);
 
        return 0;
 }
@@ -1605,9 +1751,9 @@ static int ub_bd_revalidate(struct gendisk *disk)
  */
 static int ub_bd_media_changed(struct gendisk *disk)
 {
-       struct ub_dev *sc = disk->private_data;
+       struct ub_lun *lun = disk->private_data;
 
-       if (!sc->removable)
+       if (!lun->removable)
                return 0;
 
        /*
@@ -1619,12 +1765,12 @@ static int ub_bd_media_changed(struct gendisk *disk)
         * will fail, then block layer discards the data. Since we never
         * spin drives up, such devices simply cannot be used with ub anyway.
         */
-       if (ub_sync_tur(sc) != 0) {
-               sc->changed = 1;
+       if (ub_sync_tur(lun->udev, lun) != 0) {
+               lun->changed = 1;
                return 1;
        }
 
-       return sc->changed;
+       return lun->changed;
 }
 
 static struct block_device_operations ub_bd_fops = {
@@ -1648,7 +1794,7 @@ static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 /*
  * Test if the device has a check condition on it, synchronously.
  */
-static int ub_sync_tur(struct ub_dev *sc)
+static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
 {
        struct ub_scsi_cmd *cmd;
        enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
@@ -1659,27 +1805,25 @@ static int ub_sync_tur(struct ub_dev *sc)
        init_completion(&compl);
 
        rc = -ENOMEM;
-       if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
+       if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
                goto err_alloc;
-       memset(cmd, 0, ALLOC_SIZE);
 
        cmd->cdb[0] = TEST_UNIT_READY;
        cmd->cdb_len = 6;
        cmd->dir = UB_DIR_NONE;
        cmd->state = UB_CMDST_INIT;
+       cmd->lun = lun;                 /* This may be NULL, but that's ok */
        cmd->done = ub_probe_done;
        cmd->back = &compl;
 
-       spin_lock_irqsave(&sc->lock, flags);
+       spin_lock_irqsave(sc->lock, flags);
        cmd->tag = sc->tagcnt++;
 
        rc = ub_submit_scsi(sc, cmd);
-       spin_unlock_irqrestore(&sc->lock, flags);
+       spin_unlock_irqrestore(sc->lock, flags);
 
-       if (rc != 0) {
-               printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
+       if (rc != 0)
                goto err_submit;
-       }
 
        wait_for_completion(&compl);
 
@@ -1697,9 +1841,11 @@ err_alloc:
 /*
  * Read the SCSI capacity synchronously (for probing).
  */
-static int ub_sync_read_cap(struct ub_dev *sc, struct ub_capacity *ret)
+static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
+    struct ub_capacity *ret)
 {
        struct ub_scsi_cmd *cmd;
+       struct scatterlist *sg;
        char *p;
        enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
        unsigned long flags;
@@ -1711,40 +1857,40 @@ static int ub_sync_read_cap(struct ub_dev *sc, struct ub_capacity *ret)
        init_completion(&compl);
 
        rc = -ENOMEM;
-       if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
+       if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
                goto err_alloc;
-       memset(cmd, 0, ALLOC_SIZE);
        p = (char *)cmd + sizeof(struct ub_scsi_cmd);
 
        cmd->cdb[0] = 0x25;
        cmd->cdb_len = 10;
        cmd->dir = UB_DIR_READ;
        cmd->state = UB_CMDST_INIT;
-       cmd->data = p;
+       cmd->nsg = 1;
+       sg = &cmd->sgv[0];
+       sg->page = virt_to_page(p);
+       sg->offset = (unsigned long)p & (PAGE_SIZE-1);
+       sg->length = 8;
        cmd->len = 8;
+       cmd->lun = lun;
        cmd->done = ub_probe_done;
        cmd->back = &compl;
 
-       spin_lock_irqsave(&sc->lock, flags);
+       spin_lock_irqsave(sc->lock, flags);
        cmd->tag = sc->tagcnt++;
 
        rc = ub_submit_scsi(sc, cmd);
-       spin_unlock_irqrestore(&sc->lock, flags);
+       spin_unlock_irqrestore(sc->lock, flags);
 
-       if (rc != 0) {
-               printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
+       if (rc != 0)
                goto err_submit;
-       }
 
        wait_for_completion(&compl);
 
        if (cmd->error != 0) {
-               printk("ub: reading capacity: error %d\n", cmd->error); /* P3 */
                rc = -EIO;
                goto err_read;
        }
        if (cmd->act_len != 8) {
-               printk("ub: reading capacity: size %d\n", cmd->act_len); /* P3 */
                rc = -EIO;
                goto err_read;
        }
@@ -1758,7 +1904,6 @@ static int ub_sync_read_cap(struct ub_dev *sc, struct ub_capacity *ret)
        case 2048:      shift = 2;      break;
        case 4096:      shift = 3;      break;
        default:
-               printk("ub: Bad sector size %u\n", bsize); /* P3 */
                rc = -EDOM;
                goto err_inv_bsize;
        }
@@ -1778,7 +1923,7 @@ err_alloc:
 
 /*
  */
-static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
+static void ub_probe_urb_complete(struct urb *urb)
 {
        struct completion *cop = urb->context;
        complete(cop);
@@ -1790,6 +1935,126 @@ static void ub_probe_timeout(unsigned long arg)
        complete(cop);
 }
 
+/*
+ * Reset with a Bulk reset.
+ */
+static int ub_sync_reset(struct ub_dev *sc)
+{
+       int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
+       struct usb_ctrlrequest *cr;
+       struct completion compl;
+       struct timer_list timer;
+       int rc;
+
+       init_completion(&compl);
+
+       cr = &sc->work_cr;
+       cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+       cr->bRequest = US_BULK_RESET_REQUEST;
+       cr->wValue = cpu_to_le16(0);
+       cr->wIndex = cpu_to_le16(ifnum);
+       cr->wLength = cpu_to_le16(0);
+
+       usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
+           (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
+       sc->work_urb.actual_length = 0;
+       sc->work_urb.error_count = 0;
+       sc->work_urb.status = 0;
+
+       if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
+               printk(KERN_WARNING
+                    "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
+               return rc;
+       }
+
+       init_timer(&timer);
+       timer.function = ub_probe_timeout;
+       timer.data = (unsigned long) &compl;
+       timer.expires = jiffies + UB_CTRL_TIMEOUT;
+       add_timer(&timer);
+
+       wait_for_completion(&compl);
+
+       del_timer_sync(&timer);
+       usb_kill_urb(&sc->work_urb);
+
+       return sc->work_urb.status;
+}
+
+/*
+ * Get number of LUNs by the way of Bulk GetMaxLUN command.
+ */
+static int ub_sync_getmaxlun(struct ub_dev *sc)
+{
+       int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
+       unsigned char *p;
+       enum { ALLOC_SIZE = 1 };
+       struct usb_ctrlrequest *cr;
+       struct completion compl;
+       struct timer_list timer;
+       int nluns;
+       int rc;
+
+       init_completion(&compl);
+
+       rc = -ENOMEM;
+       if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
+               goto err_alloc;
+       *p = 55;
+
+       cr = &sc->work_cr;
+       cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+       cr->bRequest = US_BULK_GET_MAX_LUN;
+       cr->wValue = cpu_to_le16(0);
+       cr->wIndex = cpu_to_le16(ifnum);
+       cr->wLength = cpu_to_le16(1);
+
+       usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
+           (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
+       sc->work_urb.actual_length = 0;
+       sc->work_urb.error_count = 0;
+       sc->work_urb.status = 0;
+
+       if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
+               goto err_submit;
+
+       init_timer(&timer);
+       timer.function = ub_probe_timeout;
+       timer.data = (unsigned long) &compl;
+       timer.expires = jiffies + UB_CTRL_TIMEOUT;
+       add_timer(&timer);
+
+       wait_for_completion(&compl);
+
+       del_timer_sync(&timer);
+       usb_kill_urb(&sc->work_urb);
+
+       if ((rc = sc->work_urb.status) < 0)
+               goto err_io;
+
+       if (sc->work_urb.actual_length != 1) {
+               nluns = 0;
+       } else {
+               if ((nluns = *p) == 55) {
+                       nluns = 0;
+               } else {
+                       /* GetMaxLUN returns the maximum LUN number */
+                       nluns += 1;
+                       if (nluns > UB_MAX_LUNS)
+                               nluns = UB_MAX_LUNS;
+               }
+       }
+
+       kfree(p);
+       return nluns;
+
+err_io:
+err_submit:
+       kfree(p);
+err_alloc:
+       return rc;
+}
+
 /*
  * Clear initial stalls.
  */
@@ -1816,7 +2081,6 @@ static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
 
        usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
            (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
-       sc->work_urb.transfer_flags = 0;
        sc->work_urb.actual_length = 0;
        sc->work_urb.error_count = 0;
        sc->work_urb.status = 0;
@@ -1876,9 +2140,9 @@ static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
        }
 
        if (ep_in == NULL || ep_out == NULL) {
-               printk(KERN_NOTICE "%s: device %u failed endpoint check\n",
-                   sc->name, sc->dev->devnum);
-               return -EIO;
+               printk(KERN_NOTICE "%s: failed endpoint check\n",
+                   sc->name);
+               return -ENODEV;
        }
 
        /* Calculate and store the pipe values */
@@ -1900,19 +2164,23 @@ static int ub_probe(struct usb_interface *intf,
     const struct usb_device_id *dev_id)
 {
        struct ub_dev *sc;
-       request_queue_t *q;
-       struct gendisk *disk;
+       int nluns;
        int rc;
        int i;
 
+       if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
+               return -ENXIO;
+
        rc = -ENOMEM;
-       if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
+       if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
                goto err_core;
-       memset(sc, 0, sizeof(struct ub_dev));
-       spin_lock_init(&sc->lock);
+       sc->lock = ub_next_lock();
+       INIT_LIST_HEAD(&sc->luns);
        usb_init_urb(&sc->work_urb);
        tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
        atomic_set(&sc->poison, 0);
+       INIT_WORK(&sc->reset_work, ub_reset_task);
+       init_waitqueue_head(&sc->reset_wait);
 
        init_timer(&sc->work_timer);
        sc->work_timer.data = (unsigned long) sc;
@@ -1921,25 +2189,25 @@ static int ub_probe(struct usb_interface *intf,
        ub_init_completion(&sc->work_done);
        sc->work_done.done = 1;         /* A little yuk, but oh well... */
 
-       rc = -ENOSR;
-       if ((sc->id = ub_id_get()) == -1)
-               goto err_id;
-       snprintf(sc->name, 8, DRV_NAME "%c", sc->id + 'a');
-
        sc->dev = interface_to_usbdev(intf);
        sc->intf = intf;
        // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
-
        usb_set_intfdata(intf, sc);
        usb_get_dev(sc->dev);
-       // usb_get_intf(sc->intf);      /* Do we need this? */
+       /*
+        * Since we give the interface struct to the block level through
+        * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
+        * oopses on close after a disconnect (kernels 2.6.16 and up).
+        */
+       usb_get_intf(sc->intf);
 
-       /* XXX Verify that we can handle the device (from descriptors) */
+       snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
+           sc->dev->bus->busnum, sc->dev->devnum);
 
-       ub_get_pipes(sc, sc->dev, intf);
+       /* XXX Verify that we can handle the device (from descriptors) */
 
-       if (device_create_file(&sc->intf->dev, &dev_attr_diag) != 0)
-               goto err_diag;
+       if (ub_get_pipes(sc, sc->dev, intf) != 0)
+               goto err_dev_desc;
 
        /*
         * At this point, all USB initialization is done, do upper layer.
@@ -1952,8 +2220,10 @@ static int ub_probe(struct usb_interface *intf,
         * This is needed to clear toggles. It is a problem only if we do
         * `rmmod ub && modprobe ub` without disconnects, but we like that.
         */
+#if 0 /* iPod Mini fails if we do this (big white iPod works) */
        ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
        ub_probe_clear_stall(sc, sc->send_bulk_pipe);
+#endif
 
        /*
         * The way this is used by the startup code is a little specific.
@@ -1970,65 +2240,92 @@ static int ub_probe(struct usb_interface *intf,
         * has to succeed, so we clear checks with an additional one here.
         * In any case it's not our business how revaliadation is implemented.
         */
-       for (i = 0; i < 3; i++) {       /* Retries for benh's key */
-               if ((rc = ub_sync_tur(sc)) <= 0) break;
+       for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
+               if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
                if (rc != 0x6) break;
                msleep(10);
        }
 
-       sc->removable = 1;              /* XXX Query this from the device */
-       sc->changed = 1;                /* ub_revalidate clears only */
-       sc->first_open = 1;
+       nluns = 1;
+       for (i = 0; i < 3; i++) {
+               if ((rc = ub_sync_getmaxlun(sc)) < 0)
+                       break;
+               if (rc != 0) {
+                       nluns = rc;
+                       break;
+               }
+               msleep(100);
+       }
 
-       ub_revalidate(sc);
-       /* This is pretty much a long term P3 */
-       printk(KERN_INFO "%s: device %u capacity nsec %ld bsize %u\n",
-           sc->name, sc->dev->devnum, sc->capacity.nsec, sc->capacity.bsize);
+       for (i = 0; i < nluns; i++) {
+               ub_probe_lun(sc, i);
+       }
+       return 0;
+
+err_dev_desc:
+       usb_set_intfdata(intf, NULL);
+       usb_put_intf(sc->intf);
+       usb_put_dev(sc->dev);
+       kfree(sc);
+err_core:
+       return rc;
+}
+
+static int ub_probe_lun(struct ub_dev *sc, int lnum)
+{
+       struct ub_lun *lun;
+       request_queue_t *q;
+       struct gendisk *disk;
+       int rc;
+
+       rc = -ENOMEM;
+       if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
+               goto err_alloc;
+       lun->num = lnum;
+
+       rc = -ENOSR;
+       if ((lun->id = ub_id_get()) == -1)
+               goto err_id;
+
+       lun->udev = sc;
+
+       snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
+           lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
+
+       lun->removable = 1;             /* XXX Query this from the device */
+       lun->changed = 1;               /* ub_revalidate clears only */
+       ub_revalidate(sc, lun);
 
-       /*
-        * Just one disk per sc currently, but maybe more.
-        */
        rc = -ENOMEM;
-       if ((disk = alloc_disk(UB_MINORS_PER_MAJOR)) == NULL)
+       if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
                goto err_diskalloc;
 
-       sc->disk = disk;
-       sprintf(disk->disk_name, DRV_NAME "%c", sc->id + 'a');
-       sprintf(disk->devfs_name, DEVFS_NAME "/%c", sc->id + 'a');
+       sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
        disk->major = UB_MAJOR;
-       disk->first_minor = sc->id * UB_MINORS_PER_MAJOR;
+       disk->first_minor = lun->id * UB_PARTS_PER_LUN;
        disk->fops = &ub_bd_fops;
-       disk->private_data = sc;
-       disk->driverfs_dev = &intf->dev;
+       disk->private_data = lun;
+       disk->driverfs_dev = &sc->intf->dev;
 
        rc = -ENOMEM;
-       if ((q = blk_init_queue(ub_bd_rq_fn, &sc->lock)) == NULL)
+       if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
                goto err_blkqinit;
 
        disk->queue = q;
 
-        // blk_queue_bounce_limit(q, hba[i]->pdev->dma_mask);
+       blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
        blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
        blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
-       // blk_queue_segment_boundary(q, CARM_SG_BOUNDARY);
+       blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
        blk_queue_max_sectors(q, UB_MAX_SECTORS);
-       blk_queue_hardsect_size(q, sc->capacity.bsize);
-
-       /*
-        * This is a serious infraction, caused by a deficiency in the
-        * USB sg interface (usb_sg_wait()). We plan to remove this once
-        * we get mileage on the driver and can justify a change to USB API.
-        * See blk_queue_bounce_limit() to understand this part.
-        *
-        * XXX And I still need to be aware of the DMA mask in the HC.
-        */
-       q->bounce_pfn = blk_max_low_pfn;
-       q->bounce_gfp = GFP_NOIO;
+       blk_queue_hardsect_size(q, lun->capacity.bsize);
 
-       q->queuedata = sc;
+       lun->disk = disk;
+       q->queuedata = lun;
+       list_add(&lun->link, &sc->luns);
 
-       set_capacity(disk, sc->capacity.nsec);
-       if (sc->removable)
+       set_capacity(disk, lun->capacity.nsec);
+       if (lun->removable)
                disk->flags |= GENHD_FL_REMOVABLE;
 
        add_disk(disk);
@@ -2038,27 +2335,29 @@ static int ub_probe(struct usb_interface *intf,
 err_blkqinit:
        put_disk(disk);
 err_diskalloc:
-       device_remove_file(&sc->intf->dev, &dev_attr_diag);
-err_diag:
-       usb_set_intfdata(intf, NULL);
-       // usb_put_intf(sc->intf);
-       usb_put_dev(sc->dev);
-       spin_lock_irq(&ub_lock);
-       ub_id_put(sc->id);
-       spin_unlock_irq(&ub_lock);
+       ub_id_put(lun->id);
 err_id:
-       kfree(sc);
-err_core:
+       kfree(lun);
+err_alloc:
        return rc;
 }
 
 static void ub_disconnect(struct usb_interface *intf)
 {
        struct ub_dev *sc = usb_get_intfdata(intf);
-       struct gendisk *disk = sc->disk;
-       request_queue_t *q = disk->queue;
+       struct list_head *p;
+       struct ub_lun *lun;
        unsigned long flags;
 
+       /*
+        * Prevent ub_bd_release from pulling the rug from under us.
+        * XXX This is starting to look like a kref.
+        * XXX Why not to take this ref at probe time?
+        */
+       spin_lock_irqsave(&ub_lock, flags);
+       sc->openc++;
+       spin_unlock_irqrestore(&ub_lock, flags);
+
        /*
         * Fence stall clearnings, operations triggered by unlinkings and so on.
         * We do not attempt to unlink any URBs, because we do not trust the
@@ -2066,6 +2365,11 @@ static void ub_disconnect(struct usb_interface *intf)
         */
        atomic_set(&sc->poison, 1);
 
+       /*
+        * Wait for reset to end, if any.
+        */
+       wait_event(sc->reset_wait, !sc->reset);
+
        /*
         * Blow away queued commands.
         *
@@ -2075,14 +2379,13 @@ static void ub_disconnect(struct usb_interface *intf)
         * and the whole queue drains. So, we just use this code to
         * print warnings.
         */
-       spin_lock_irqsave(&sc->lock, flags);
+       spin_lock_irqsave(sc->lock, flags);
        {
                struct ub_scsi_cmd *cmd;
                int cnt = 0;
-               while ((cmd = ub_cmdq_pop(sc)) != NULL) {
+               while ((cmd = ub_cmdq_peek(sc)) != NULL) {
                        cmd->error = -ENOTCONN;
                        cmd->state = UB_CMDST_DONE;
-                       ub_cmdtr_state(sc, cmd);
                        ub_cmdq_pop(sc);
                        (*cmd->done)(sc, cmd);
                        cnt++;
@@ -2092,33 +2395,32 @@ static void ub_disconnect(struct usb_interface *intf)
                            "%d was queued after shutdown\n", sc->name, cnt);
                }
        }
-       spin_unlock_irqrestore(&sc->lock, flags);
+       spin_unlock_irqrestore(sc->lock, flags);
 
        /*
-        * Unregister the upper layer, this waits for all commands to end.
+        * Unregister the upper layer.
         */
-       if (disk->flags & GENHD_FL_UP)
-               del_gendisk(disk);
-       if (q)
-               blk_cleanup_queue(q);
+       list_for_each (p, &sc->luns) {
+               lun = list_entry(p, struct ub_lun, link);
+               del_gendisk(lun->disk);
+               /*
+                * I wish I could do:
+                *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
+                * As it is, we rely on our internal poisoning and let
+                * the upper levels to spin furiously failing all the I/O.
+                */
+       }
 
        /*
-        * We really expect blk_cleanup_queue() to wait, so no amount
-        * of paranoya is too much.
-        *
-        * Taking a lock on a structure which is about to be freed
-        * is very nonsensual. Here it is largely a way to do a debug freeze,
-        * and a bracket which shows where the nonsensual code segment ends.
-        *
         * Testing for -EINPROGRESS is always a bug, so we are bending
         * the rules a little.
         */
-       spin_lock_irqsave(&sc->lock, flags);
+       spin_lock_irqsave(sc->lock, flags);
        if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
                printk(KERN_WARNING "%s: "
                    "URB is active after disconnect\n", sc->name);
        }
-       spin_unlock_irqrestore(&sc->lock, flags);
+       spin_unlock_irqrestore(sc->lock, flags);
 
        /*
         * There is virtually no chance that other CPU runs times so long
@@ -2132,21 +2434,10 @@ static void ub_disconnect(struct usb_interface *intf)
         * and no URBs left in transit.
         */
 
-       device_remove_file(&sc->intf->dev, &dev_attr_diag);
-       usb_set_intfdata(intf, NULL);
-       // usb_put_intf(sc->intf);
-       sc->intf = NULL;
-       usb_put_dev(sc->dev);
-       sc->dev = NULL;
-
-       spin_lock_irqsave(&ub_lock, flags);
-       if (sc->openc == 0)
-               ub_cleanup(sc);
-       spin_unlock_irqrestore(&ub_lock, flags);
+       ub_put(sc);
 }
 
-struct usb_driver ub_driver = {
-       .owner =        THIS_MODULE,
+static struct usb_driver ub_driver = {
        .name =         "ub",
        .probe =        ub_probe,
        .disconnect =   ub_disconnect,
@@ -2156,21 +2447,21 @@ struct usb_driver ub_driver = {
 static int __init ub_init(void)
 {
        int rc;
+       int i;
 
-       /* P3 */ printk("ub: sizeof ub_scsi_cmd %zu ub_dev %zu\n",
-                       sizeof(struct ub_scsi_cmd), sizeof(struct ub_dev));
+       for (i = 0; i < UB_QLOCK_NUM; i++)
+               spin_lock_init(&ub_qlockv[i]);
 
        if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
                goto err_regblkdev;
-       devfs_mk_dir(DEVFS_NAME);
 
        if ((rc = usb_register(&ub_driver)) != 0)
                goto err_register;
 
+       usb_usual_set_present(USB_US_TYPE_UB);
        return 0;
 
 err_register:
-       devfs_remove(DEVFS_NAME);
        unregister_blkdev(UB_MAJOR, DRV_NAME);
 err_regblkdev:
        return rc;
@@ -2180,8 +2471,8 @@ static void __exit ub_exit(void)
 {
        usb_deregister(&ub_driver);
 
-       devfs_remove(DEVFS_NAME);
        unregister_blkdev(UB_MAJOR, DRV_NAME);
+       usb_usual_clear_present(USB_US_TYPE_UB);
 }
 
 module_init(ub_init);