drivers/scsi/hosts.c

   1 /*
   2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   4  *          Copyright (C) 2002-2003 Christoph Hellwig
   5  *
   6  *  mid to lowlevel SCSI driver interface
   7  *      Initial versions: Drew Eckhardt
   8  *      Subsequent revisions: Eric Youngdale
   9  *
  10  *  <drew@colorado.edu>
  11  *
  12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  14  *     August 4, 1999 Fred Lewis, Intel DuPont
  15  *
  16  *  Updated to reflect the new initialization scheme for the higher
  17  *  level of scsi drivers (sd/sr/st)
  18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  19  *
  20  *  Restructured scsi_host lists and associated functions.
  21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/kernel.h>
  27 #include <linux/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/init.h>
  30 #include <linux/completion.h>
  31
  32 #include <scsi/scsi_device.h>
  33 #include <scsi/scsi_host.h>
  34 #include <scsi/scsi_transport.h>
  35
  36 #include "scsi_priv.h"
  37 #include "scsi_logging.h"
  38
  39
  40 static int scsi_host_next_hn;           /* host_no for next new host */
  41
  42
  43 static void scsi_host_cls_release(struct class_device *class_dev)
  44 {
  45         put_device(&class_to_shost(class_dev)->shost_gendev);
  46 }
  47
  48 static struct class shost_class = {
  49         .name           = "scsi_host",
  50         .release        = scsi_host_cls_release,
  51 };
  52
  53 /**
  54  * scsi_host_cancel - cancel outstanding IO to this host
  55  * @shost:      pointer to struct Scsi_Host
  56  * recovery:    recovery requested to run.
  57  **/
  58 void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
  59 {
  60         struct scsi_device *sdev;
  61
  62         set_bit(SHOST_CANCEL, &shost->shost_state);
  63         shost_for_each_device(sdev, shost) {
  64                 scsi_device_cancel(sdev, recovery);
  65         }
  66         wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
  67                                                 &shost->shost_state)));
  68 }
  69
  70 /**
  71  * scsi_remove_host - remove a scsi host
  72  * @shost:      a pointer to a scsi host to remove
  73  **/
  74 void scsi_remove_host(struct Scsi_Host *shost)
  75 {
  76         scsi_forget_host(shost);
  77         scsi_host_cancel(shost, 0);
  78         scsi_proc_host_rm(shost);
  79
  80         set_bit(SHOST_DEL, &shost->shost_state);
  81
  82         if (shost->transportt->host_destroy)
  83                 shost->transportt->host_destroy(shost);
  84         class_device_unregister(&shost->shost_classdev);
  85         if (shost->transport_classdev.class)
  86                 class_device_unregister(&shost->transport_classdev);
  87         device_del(&shost->shost_gendev);
  88 }
  89
  90 /**
  91  * scsi_add_host - add a scsi host
  92  * @shost:      scsi host pointer to add
  93  * @dev:        a struct device of type scsi class
  94  *
  95  * Return value:
  96  *      0 on success / != 0 for error
  97  **/
  98 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
  99 {
 100         struct scsi_host_template *sht = shost->hostt;
 101         int error = -EINVAL;
 102
 103         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 104                         sht->info ? sht->info(shost) : sht->name);
 105
 106         if (!shost->can_queue) {
 107                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 108                                 sht->name);
 109                 goto out;
 110         }
 111
 112         if (!shost->shost_gendev.parent)
 113                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 114
 115         error = device_add(&shost->shost_gendev);
 116         if (error)
 117                 goto out;
 118
 119         set_bit(SHOST_ADD, &shost->shost_state);
 120         get_device(shost->shost_gendev.parent);
 121
 122         error = class_device_add(&shost->shost_classdev);
 123         if (error)
 124                 goto out_del_gendev;
 125
 126         get_device(&shost->shost_gendev);
 127
 128         if (shost->transportt->host_size &&
 129             (shost->shost_data = kmalloc(shost->transportt->host_size,
 130                                          GFP_KERNEL)) == NULL)
 131                 goto out_del_classdev;
 132
 133         if (shost->transportt->host_setup)
 134                 shost->transportt->host_setup(shost);
 135
 136         error = scsi_sysfs_add_host(shost);
 137         if (error)
 138                 goto out_destroy_host;
 139
 140         scsi_proc_host_add(shost);
 141         return error;
 142
 143  out_destroy_host:
 144         if (shost->transportt->host_destroy)
 145                 shost->transportt->host_destroy(shost);
 146  out_del_classdev:
 147         class_device_del(&shost->shost_classdev);
 148  out_del_gendev:
 149         device_del(&shost->shost_gendev);
 150  out:
 151         return error;
 152 }
 153
 154 static void scsi_host_dev_release(struct device *dev)
 155 {
 156         struct Scsi_Host *shost = dev_to_shost(dev);
 157         struct device *parent = dev->parent;
 158
 159         if (shost->ehandler) {
 160                 DECLARE_COMPLETION(sem);
 161                 shost->eh_notify = &sem;
 162                 shost->eh_kill = 1;
 163                 up(shost->eh_wait);
 164                 wait_for_completion(&sem);
 165                 shost->eh_notify = NULL;
 166         }
 167
 168         scsi_proc_hostdir_rm(shost->hostt);
 169         scsi_destroy_command_freelist(shost);
 170         kfree(shost->shost_data);
 171
 172         /*
 173          * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
 174          * during probing without performing a scsi_set_device() in between.
 175          * In this case dev->parent is NULL.
 176          */
 177         if (parent)
 178                 put_device(parent);
 179         kfree(shost);
 180 }
 181
 182 /**
 183  * scsi_host_alloc - register a scsi host adapter instance.
 184  * @sht:        pointer to scsi host template
 185  * @privsize:   extra bytes to allocate for driver
 186  *
 187  * Note:
 188  *      Allocate a new Scsi_Host and perform basic initialization.
 189  *      The host is not published to the scsi midlayer until scsi_add_host
 190  *      is called.
 191  *
 192  * Return value:
 193  *      Pointer to a new Scsi_Host
 194  **/
 195 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 196 {
 197         struct Scsi_Host *shost;
 198         int gfp_mask = GFP_KERNEL, rval;
 199         DECLARE_COMPLETION(complete);
 200
 201         if (sht->unchecked_isa_dma && privsize)
 202                 gfp_mask |= __GFP_DMA;
 203
 204         /* Check to see if this host has any error handling facilities */
 205         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 206             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 207             !sht->eh_host_reset_handler) {
 208                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 209                                 "ERROR: This is not a safe way to run your "
 210                                         "SCSI host\n"
 211                                 "ERROR: The error handling must be added to "
 212                                 "this driver\n", sht->proc_name);
 213                 dump_stack();
 214         }
 215
 216         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 217         if (!shost)
 218                 return NULL;
 219         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 220
 221         spin_lock_init(&shost->default_lock);
 222         scsi_assign_lock(shost, &shost->default_lock);
 223         INIT_LIST_HEAD(&shost->__devices);
 224         INIT_LIST_HEAD(&shost->eh_cmd_q);
 225         INIT_LIST_HEAD(&shost->starved_list);
 226         init_waitqueue_head(&shost->host_wait);
 227
 228         init_MUTEX(&shost->scan_mutex);
 229
 230         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 231         shost->dma_channel = 0xff;
 232
 233         /* These three are default values which can be overridden */
 234         shost->max_channel = 0;
 235         shost->max_id = 8;
 236         shost->max_lun = 8;
 237
 238         /* Give each shost a default transportt */
 239         shost->transportt = &blank_transport_template;
 240
 241         /*
 242          * All drivers right now should be able to handle 12 byte
 243          * commands.  Every so often there are requests for 16 byte
 244          * commands, but individual low-level drivers need to certify that
 245          * they actually do something sensible with such commands.
 246          */
 247         shost->max_cmd_len = 12;
 248         shost->hostt = sht;
 249         shost->this_id = sht->this_id;
 250         shost->can_queue = sht->can_queue;
 251         shost->sg_tablesize = sht->sg_tablesize;
 252         shost->cmd_per_lun = sht->cmd_per_lun;
 253         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 254         shost->use_clustering = sht->use_clustering;
 255
 256         if (sht->max_host_blocked)
 257                 shost->max_host_blocked = sht->max_host_blocked;
 258         else
 259                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 260
 261         /*
 262          * If the driver imposes no hard sector transfer limit, start at
 263          * machine infinity initially.
 264          */
 265         if (sht->max_sectors)
 266                 shost->max_sectors = sht->max_sectors;
 267         else
 268                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 269
 270         /*
 271          * assume a 4GB boundary, if not set
 272          */
 273         if (sht->dma_boundary)
 274                 shost->dma_boundary = sht->dma_boundary;
 275         else
 276                 shost->dma_boundary = 0xffffffff;
 277
 278         rval = scsi_setup_command_freelist(shost);
 279         if (rval)
 280                 goto fail_kfree;
 281
 282         device_initialize(&shost->shost_gendev);
 283         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 284                 shost->host_no);
 285         shost->shost_gendev.release = scsi_host_dev_release;
 286
 287         class_device_initialize(&shost->shost_classdev);
 288         shost->shost_classdev.dev = &shost->shost_gendev;
 289         shost->shost_classdev.class = &shost_class;
 290         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 291                   shost->host_no);
 292
 293         shost->eh_notify = &complete;
 294         rval = kernel_thread(scsi_error_handler, shost, 0);
 295         if (rval < 0)
 296                 goto fail_destroy_freelist;
 297         wait_for_completion(&complete);
 298         shost->eh_notify = NULL;
 299
 300         scsi_proc_hostdir_add(shost->hostt);
 301         return shost;
 302
 303  fail_destroy_freelist:
 304         scsi_destroy_command_freelist(shost);
 305  fail_kfree:
 306         kfree(shost);
 307         return NULL;
 308 }
 309
 310 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 311 {
 312         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 313
 314         if (!sht->detect) {
 315                 printk(KERN_WARNING "scsi_register() called on new-style "
 316                                     "template for driver %s\n", sht->name);
 317                 dump_stack();
 318         }
 319
 320         if (shost)
 321                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 322         return shost;
 323 }
 324
 325 void scsi_unregister(struct Scsi_Host *shost)
 326 {
 327         list_del(&shost->sht_legacy_list);
 328         scsi_host_put(shost);
 329 }
 330
 331 /**
 332  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 333  *
 334  * @hostnum:    host number to locate
 335  *
 336  * Return value:
 337  *      A pointer to located Scsi_Host or NULL.
 338  **/
 339 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 340 {
 341         struct class *class = &shost_class;
 342         struct class_device *cdev;
 343         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 344
 345         down_read(&class->subsys.rwsem);
 346         list_for_each_entry(cdev, &class->children, node) {
 347                 p = class_to_shost(cdev);
 348                 if (p->host_no == hostnum) {
 349                         shost = scsi_host_get(p);
 350                         break;
 351                 }
 352         }
 353         up_read(&class->subsys.rwsem);
 354
 355         return shost;
 356 }
 357
 358 /**
 359  * scsi_host_get - inc a Scsi_Host ref count
 360  * @shost:      Pointer to Scsi_Host to inc.
 361  **/
 362 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 363 {
 364         if (test_bit(SHOST_DEL, &shost->shost_state) ||
 365                 !get_device(&shost->shost_gendev))
 366                 return NULL;
 367         return shost;
 368 }
 369
 370 /**
 371  * scsi_host_put - dec a Scsi_Host ref count
 372  * @shost:      Pointer to Scsi_Host to dec.
 373  **/
 374 void scsi_host_put(struct Scsi_Host *shost)
 375 {
 376         put_device(&shost->shost_gendev);
 377 }
 378
 379 int scsi_init_hosts(void)
 380 {
 381         return class_register(&shost_class);
 382 }
 383
 384 void scsi_exit_hosts(void)
 385 {
 386         class_unregister(&shost_class);
 387 }