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                 if (shost->transportt->host_statistics)
  87                         sysfs_remove_group(&shost->transport_classdev.kobj,
  88                                 shost->transportt->host_statistics);
  89                 class_device_unregister(&shost->transport_classdev);
  90         }
  91         device_del(&shost->shost_gendev);
  92 }
  93 EXPORT_SYMBOL(scsi_remove_host);
  94
  95 /**
  96  * scsi_add_host - add a scsi host
  97  * @shost:      scsi host pointer to add
  98  * @dev:        a struct device of type scsi class
  99  *
 100  * Return value:
 101  *      0 on success / != 0 for error
 102  **/
 103 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 104 {
 105         struct scsi_host_template *sht = shost->hostt;
 106         int error = -EINVAL;
 107
 108         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 109                         sht->info ? sht->info(shost) : sht->name);
 110
 111         if (!shost->can_queue) {
 112                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 113                                 sht->name);
 114                 goto out;
 115         }
 116
 117         if (!shost->shost_gendev.parent)
 118                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 119
 120         error = device_add(&shost->shost_gendev);
 121         if (error)
 122                 goto out;
 123
 124         set_bit(SHOST_ADD, &shost->shost_state);
 125         get_device(shost->shost_gendev.parent);
 126
 127         error = class_device_add(&shost->shost_classdev);
 128         if (error)
 129                 goto out_del_gendev;
 130
 131         get_device(&shost->shost_gendev);
 132
 133         if (shost->transportt->host_size &&
 134             (shost->shost_data = kmalloc(shost->transportt->host_size,
 135                                          GFP_KERNEL)) == NULL)
 136                 goto out_del_classdev;
 137
 138         if (shost->transportt->host_setup)
 139                 shost->transportt->host_setup(shost);
 140
 141         error = scsi_sysfs_add_host(shost);
 142         if (error)
 143                 goto out_destroy_host;
 144
 145         scsi_proc_host_add(shost);
 146         return error;
 147
 148  out_destroy_host:
 149         if (shost->transportt->host_destroy)
 150                 shost->transportt->host_destroy(shost);
 151  out_del_classdev:
 152         class_device_del(&shost->shost_classdev);
 153  out_del_gendev:
 154         device_del(&shost->shost_gendev);
 155  out:
 156         return error;
 157 }
 158 EXPORT_SYMBOL(scsi_add_host);
 159
 160 static void scsi_host_dev_release(struct device *dev)
 161 {
 162         struct Scsi_Host *shost = dev_to_shost(dev);
 163         struct device *parent = dev->parent;
 164
 165         if (shost->ehandler) {
 166                 DECLARE_COMPLETION(sem);
 167                 shost->eh_notify = &sem;
 168                 shost->eh_kill = 1;
 169                 up(shost->eh_wait);
 170                 wait_for_completion(&sem);
 171                 shost->eh_notify = NULL;
 172         }
 173
 174         scsi_proc_hostdir_rm(shost->hostt);
 175         scsi_destroy_command_freelist(shost);
 176         kfree(shost->shost_data);
 177
 178         /*
 179          * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
 180          * during probing without performing a scsi_set_device() in between.
 181          * In this case dev->parent is NULL.
 182          */
 183         if (parent)
 184                 put_device(parent);
 185         kfree(shost);
 186 }
 187
 188 /**
 189  * scsi_host_alloc - register a scsi host adapter instance.
 190  * @sht:        pointer to scsi host template
 191  * @privsize:   extra bytes to allocate for driver
 192  *
 193  * Note:
 194  *      Allocate a new Scsi_Host and perform basic initialization.
 195  *      The host is not published to the scsi midlayer until scsi_add_host
 196  *      is called.
 197  *
 198  * Return value:
 199  *      Pointer to a new Scsi_Host
 200  **/
 201 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 202 {
 203         struct Scsi_Host *shost;
 204         int gfp_mask = GFP_KERNEL, rval;
 205         DECLARE_COMPLETION(complete);
 206
 207         if (sht->unchecked_isa_dma && privsize)
 208                 gfp_mask |= __GFP_DMA;
 209
 210         /* Check to see if this host has any error handling facilities */
 211         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 212             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 213             !sht->eh_host_reset_handler) {
 214                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 215                                 "ERROR: This is not a safe way to run your "
 216                                         "SCSI host\n"
 217                                 "ERROR: The error handling must be added to "
 218                                 "this driver\n", sht->proc_name);
 219                 dump_stack();
 220         }
 221
 222         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 223         if (!shost)
 224                 return NULL;
 225         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 226
 227         spin_lock_init(&shost->default_lock);
 228         scsi_assign_lock(shost, &shost->default_lock);
 229         INIT_LIST_HEAD(&shost->__devices);
 230         INIT_LIST_HEAD(&shost->eh_cmd_q);
 231         INIT_LIST_HEAD(&shost->starved_list);
 232         init_waitqueue_head(&shost->host_wait);
 233
 234         init_MUTEX(&shost->scan_mutex);
 235
 236         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 237         shost->dma_channel = 0xff;
 238
 239         /* These three are default values which can be overridden */
 240         shost->max_channel = 0;
 241         shost->max_id = 8;
 242         shost->max_lun = 8;
 243
 244         /* Give each shost a default transportt */
 245         shost->transportt = &blank_transport_template;
 246
 247         /*
 248          * All drivers right now should be able to handle 12 byte
 249          * commands.  Every so often there are requests for 16 byte
 250          * commands, but individual low-level drivers need to certify that
 251          * they actually do something sensible with such commands.
 252          */
 253         shost->max_cmd_len = 12;
 254         shost->hostt = sht;
 255         shost->this_id = sht->this_id;
 256         shost->can_queue = sht->can_queue;
 257         shost->sg_tablesize = sht->sg_tablesize;
 258         shost->cmd_per_lun = sht->cmd_per_lun;
 259         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 260         shost->use_clustering = sht->use_clustering;
 261
 262         if (sht->max_host_blocked)
 263                 shost->max_host_blocked = sht->max_host_blocked;
 264         else
 265                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 266
 267         /*
 268          * If the driver imposes no hard sector transfer limit, start at
 269          * machine infinity initially.
 270          */
 271         if (sht->max_sectors)
 272                 shost->max_sectors = sht->max_sectors;
 273         else
 274                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 275
 276         /*
 277          * assume a 4GB boundary, if not set
 278          */
 279         if (sht->dma_boundary)
 280                 shost->dma_boundary = sht->dma_boundary;
 281         else
 282                 shost->dma_boundary = 0xffffffff;
 283
 284         rval = scsi_setup_command_freelist(shost);
 285         if (rval)
 286                 goto fail_kfree;
 287
 288         device_initialize(&shost->shost_gendev);
 289         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 290                 shost->host_no);
 291         shost->shost_gendev.release = scsi_host_dev_release;
 292
 293         class_device_initialize(&shost->shost_classdev);
 294         shost->shost_classdev.dev = &shost->shost_gendev;
 295         shost->shost_classdev.class = &shost_class;
 296         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 297                   shost->host_no);
 298
 299         shost->eh_notify = &complete;
 300         rval = kernel_thread(scsi_error_handler, shost, 0);
 301         if (rval < 0)
 302                 goto fail_destroy_freelist;
 303         wait_for_completion(&complete);
 304         shost->eh_notify = NULL;
 305
 306         scsi_proc_hostdir_add(shost->hostt);
 307         return shost;
 308
 309  fail_destroy_freelist:
 310         scsi_destroy_command_freelist(shost);
 311  fail_kfree:
 312         kfree(shost);
 313         return NULL;
 314 }
 315 EXPORT_SYMBOL(scsi_host_alloc);
 316
 317 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 318 {
 319         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 320
 321         if (!sht->detect) {
 322                 printk(KERN_WARNING "scsi_register() called on new-style "
 323                                     "template for driver %s\n", sht->name);
 324                 dump_stack();
 325         }
 326
 327         if (shost)
 328                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 329         return shost;
 330 }
 331 EXPORT_SYMBOL(scsi_register);
 332
 333 void scsi_unregister(struct Scsi_Host *shost)
 334 {
 335         list_del(&shost->sht_legacy_list);
 336         scsi_host_put(shost);
 337 }
 338 EXPORT_SYMBOL(scsi_unregister);
 339
 340 /**
 341  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 342  *
 343  * @hostnum:    host number to locate
 344  *
 345  * Return value:
 346  *      A pointer to located Scsi_Host or NULL.
 347  **/
 348 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 349 {
 350         struct class *class = &shost_class;
 351         struct class_device *cdev;
 352         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 353
 354         down_read(&class->subsys.rwsem);
 355         list_for_each_entry(cdev, &class->children, node) {
 356                 p = class_to_shost(cdev);
 357                 if (p->host_no == hostnum) {
 358                         shost = scsi_host_get(p);
 359                         break;
 360                 }
 361         }
 362         up_read(&class->subsys.rwsem);
 363
 364         return shost;
 365 }
 366 EXPORT_SYMBOL(scsi_host_lookup);
 367
 368 /**
 369  * scsi_host_get - inc a Scsi_Host ref count
 370  * @shost:      Pointer to Scsi_Host to inc.
 371  **/
 372 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 373 {
 374         if (test_bit(SHOST_DEL, &shost->shost_state) ||
 375                 !get_device(&shost->shost_gendev))
 376                 return NULL;
 377         return shost;
 378 }
 379 EXPORT_SYMBOL(scsi_host_get);
 380
 381 /**
 382  * scsi_host_put - dec a Scsi_Host ref count
 383  * @shost:      Pointer to Scsi_Host to dec.
 384  **/
 385 void scsi_host_put(struct Scsi_Host *shost)
 386 {
 387         put_device(&shost->shost_gendev);
 388 }
 389 EXPORT_SYMBOL(scsi_host_put);
 390
 391 int scsi_init_hosts(void)
 392 {
 393         return class_register(&shost_class);
 394 }
 395
 396 void scsi_exit_hosts(void)
 397 {
 398         class_unregister(&shost_class);
 399 }