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         class_device_unregister(&shost->shost_classdev);
  83         if (shost->transport_classdev.class)
  84                 class_device_unregister(&shost->transport_classdev);
  85         device_del(&shost->shost_gendev);
  86 }
  87
  88 /**
  89  * scsi_add_host - add a scsi host
  90  * @shost:      scsi host pointer to add
  91  * @dev:        a struct device of type scsi class
  92  *
  93  * Return value:
  94  *      0 on success / != 0 for error
  95  **/
  96 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
  97 {
  98         struct scsi_host_template *sht = shost->hostt;
  99         int error = -EINVAL;
 100
 101         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 102                         sht->info ? sht->info(shost) : sht->name);
 103
 104         if (!shost->can_queue) {
 105                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 106                                 sht->name);
 107                 goto out;
 108         }
 109
 110         if (!shost->shost_gendev.parent)
 111                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 112
 113         error = device_add(&shost->shost_gendev);
 114         if (error)
 115                 goto out;
 116
 117         set_bit(SHOST_ADD, &shost->shost_state);
 118         get_device(shost->shost_gendev.parent);
 119
 120         error = class_device_add(&shost->shost_classdev);
 121         if (error)
 122                 goto out_del_gendev;
 123
 124         get_device(&shost->shost_gendev);
 125
 126         if (shost->transportt->host_size &&
 127             (shost->shost_data = kmalloc(shost->transportt->host_size,
 128                                          GFP_KERNEL)) == NULL)
 129                 goto out_del_classdev;
 130
 131         if (shost->transportt->host_setup)
 132                 shost->transportt->host_setup(shost);
 133
 134         error = scsi_sysfs_add_host(shost);
 135         if (error)
 136                 goto out_del_classdev;
 137
 138         scsi_proc_host_add(shost);
 139         return error;
 140
 141  out_del_classdev:
 142         class_device_del(&shost->shost_classdev);
 143  out_del_gendev:
 144         device_del(&shost->shost_gendev);
 145  out:
 146         return error;
 147 }
 148
 149 static void scsi_host_dev_release(struct device *dev)
 150 {
 151         struct Scsi_Host *shost = dev_to_shost(dev);
 152         struct device *parent = dev->parent;
 153
 154         if (shost->ehandler) {
 155                 DECLARE_COMPLETION(sem);
 156                 shost->eh_notify = &sem;
 157                 shost->eh_kill = 1;
 158                 up(shost->eh_wait);
 159                 wait_for_completion(&sem);
 160                 shost->eh_notify = NULL;
 161         }
 162
 163         scsi_proc_hostdir_rm(shost->hostt);
 164         scsi_destroy_command_freelist(shost);
 165         kfree(shost->shost_data);
 166
 167         /*
 168          * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
 169          * during probing without performing a scsi_set_device() in between.
 170          * In this case dev->parent is NULL.
 171          */
 172         if (parent)
 173                 put_device(parent);
 174         kfree(shost);
 175 }
 176
 177 /**
 178  * scsi_host_alloc - register a scsi host adapter instance.
 179  * @sht:        pointer to scsi host template
 180  * @privsize:   extra bytes to allocate for driver
 181  *
 182  * Note:
 183  *      Allocate a new Scsi_Host and perform basic initialization.
 184  *      The host is not published to the scsi midlayer until scsi_add_host
 185  *      is called.
 186  *
 187  * Return value:
 188  *      Pointer to a new Scsi_Host
 189  **/
 190 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 191 {
 192         struct Scsi_Host *shost;
 193         int gfp_mask = GFP_KERNEL, rval;
 194         DECLARE_COMPLETION(complete);
 195
 196         if (sht->unchecked_isa_dma && privsize)
 197                 gfp_mask |= __GFP_DMA;
 198
 199         /* Check to see if this host has any error handling facilities */
 200         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 201             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 202             !sht->eh_host_reset_handler) {
 203                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 204                                 "ERROR: This is not a safe way to run your "
 205                                         "SCSI host\n"
 206                                 "ERROR: The error handling must be added to "
 207                                 "this driver\n", sht->proc_name);
 208                 dump_stack();
 209         }
 210
 211         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 212         if (!shost)
 213                 return NULL;
 214         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 215
 216         spin_lock_init(&shost->default_lock);
 217         scsi_assign_lock(shost, &shost->default_lock);
 218         INIT_LIST_HEAD(&shost->__devices);
 219         INIT_LIST_HEAD(&shost->eh_cmd_q);
 220         INIT_LIST_HEAD(&shost->starved_list);
 221         init_waitqueue_head(&shost->host_wait);
 222
 223         init_MUTEX(&shost->scan_mutex);
 224
 225         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 226         shost->dma_channel = 0xff;
 227
 228         /* These three are default values which can be overridden */
 229         shost->max_channel = 0;
 230         shost->max_id = 8;
 231         shost->max_lun = 8;
 232
 233         /* Give each shost a default transportt */
 234         shost->transportt = &blank_transport_template;
 235
 236         /*
 237          * All drivers right now should be able to handle 12 byte
 238          * commands.  Every so often there are requests for 16 byte
 239          * commands, but individual low-level drivers need to certify that
 240          * they actually do something sensible with such commands.
 241          */
 242         shost->max_cmd_len = 12;
 243         shost->hostt = sht;
 244         shost->this_id = sht->this_id;
 245         shost->can_queue = sht->can_queue;
 246         shost->sg_tablesize = sht->sg_tablesize;
 247         shost->cmd_per_lun = sht->cmd_per_lun;
 248         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 249         shost->use_clustering = sht->use_clustering;
 250
 251         if (sht->max_host_blocked)
 252                 shost->max_host_blocked = sht->max_host_blocked;
 253         else
 254                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 255
 256         /*
 257          * If the driver imposes no hard sector transfer limit, start at
 258          * machine infinity initially.
 259          */
 260         if (sht->max_sectors)
 261                 shost->max_sectors = sht->max_sectors;
 262         else
 263                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 264
 265         /*
 266          * assume a 4GB boundary, if not set
 267          */
 268         if (sht->dma_boundary)
 269                 shost->dma_boundary = sht->dma_boundary;
 270         else
 271                 shost->dma_boundary = 0xffffffff;
 272
 273         rval = scsi_setup_command_freelist(shost);
 274         if (rval)
 275                 goto fail_kfree;
 276
 277         device_initialize(&shost->shost_gendev);
 278         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 279                 shost->host_no);
 280         shost->shost_gendev.release = scsi_host_dev_release;
 281
 282         class_device_initialize(&shost->shost_classdev);
 283         shost->shost_classdev.dev = &shost->shost_gendev;
 284         shost->shost_classdev.class = &shost_class;
 285         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 286                   shost->host_no);
 287
 288         shost->eh_notify = &complete;
 289         rval = kernel_thread(scsi_error_handler, shost, 0);
 290         if (rval < 0)
 291                 goto fail_destroy_freelist;
 292         wait_for_completion(&complete);
 293         shost->eh_notify = NULL;
 294
 295         scsi_proc_hostdir_add(shost->hostt);
 296         return shost;
 297
 298  fail_destroy_freelist:
 299         scsi_destroy_command_freelist(shost);
 300  fail_kfree:
 301         kfree(shost);
 302         return NULL;
 303 }
 304
 305 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 306 {
 307         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 308
 309         if (!sht->detect) {
 310                 printk(KERN_WARNING "scsi_register() called on new-style "
 311                                     "template for driver %s\n", sht->name);
 312                 dump_stack();
 313         }
 314
 315         if (shost)
 316                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 317         return shost;
 318 }
 319
 320 void scsi_unregister(struct Scsi_Host *shost)
 321 {
 322         list_del(&shost->sht_legacy_list);
 323         scsi_host_put(shost);
 324 }
 325
 326 /**
 327  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 328  *
 329  * @hostnum:    host number to locate
 330  *
 331  * Return value:
 332  *      A pointer to located Scsi_Host or NULL.
 333  **/
 334 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 335 {
 336         struct class *class = &shost_class;
 337         struct class_device *cdev;
 338         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 339
 340         down_read(&class->subsys.rwsem);
 341         list_for_each_entry(cdev, &class->children, node) {
 342                 p = class_to_shost(cdev);
 343                 if (p->host_no == hostnum) {
 344                         shost = scsi_host_get(p);
 345                         break;
 346                 }
 347         }
 348         up_read(&class->subsys.rwsem);
 349
 350         return shost;
 351 }
 352
 353 /**
 354  * scsi_host_get - inc a Scsi_Host ref count
 355  * @shost:      Pointer to Scsi_Host to inc.
 356  **/
 357 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 358 {
 359         if (test_bit(SHOST_DEL, &shost->shost_state) ||
 360                 !get_device(&shost->shost_gendev))
 361                 return NULL;
 362         return shost;
 363 }
 364
 365 /**
 366  * scsi_host_put - dec a Scsi_Host ref count
 367  * @shost:      Pointer to Scsi_Host to dec.
 368  **/
 369 void scsi_host_put(struct Scsi_Host *shost)
 370 {
 371         put_device(&shost->shost_gendev);
 372 }
 373
 374 int scsi_init_hosts(void)
 375 {
 376         return class_register(&shost_class);
 377 }
 378
 379 void scsi_exit_hosts(void)
 380 {
 381         class_unregister(&shost_class);
 382 }