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 static int scsi_device_cancel_cb(struct device *dev, void *data)
  54 {
  55         return scsi_device_cancel(to_scsi_device(dev), *(int *)data);
  56 }
  57
  58 /**
  59  * scsi_host_cancel - cancel outstanding IO to this host
  60  * @shost:      pointer to struct Scsi_Host
  61  * recovery:    recovery requested to run.
  62  **/
  63 void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
  64 {
  65         set_bit(SHOST_CANCEL, &shost->shost_state);
  66         device_for_each_child(&shost->shost_gendev, &recovery,
  67                               scsi_device_cancel_cb);
  68         wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
  69                                                 &shost->shost_state)));
  70 }
  71
  72 /**
  73  * scsi_remove_host - remove a scsi host
  74  * @shost:      a pointer to a scsi host to remove
  75  **/
  76 void scsi_remove_host(struct Scsi_Host *shost)
  77 {
  78         scsi_forget_host(shost);
  79         scsi_host_cancel(shost, 0);
  80         scsi_proc_host_rm(shost);
  81
  82         set_bit(SHOST_DEL, &shost->shost_state);
  83
  84         class_device_unregister(&shost->shost_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;
 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                 return -EINVAL;
 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         error = scsi_sysfs_add_host(shost);
 127         if (error)
 128                 goto out_del_classdev;
 129
 130         scsi_proc_host_add(shost);
 131         return error;
 132
 133  out_del_classdev:
 134         class_device_del(&shost->shost_classdev);
 135  out_del_gendev:
 136         device_del(&shost->shost_gendev);
 137  out:
 138         return error;
 139 }
 140
 141 static void scsi_host_dev_release(struct device *dev)
 142 {
 143         struct Scsi_Host *shost = dev_to_shost(dev);
 144         struct device *parent = dev->parent;
 145
 146         if (shost->ehandler) {
 147                 DECLARE_COMPLETION(sem);
 148                 shost->eh_notify = &sem;
 149                 shost->eh_kill = 1;
 150                 up(shost->eh_wait);
 151                 wait_for_completion(&sem);
 152                 shost->eh_notify = NULL;
 153         }
 154
 155         scsi_proc_hostdir_rm(shost->hostt);
 156         scsi_destroy_command_freelist(shost);
 157
 158         /*
 159          * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
 160          * during probing without performing a scsi_set_device() in between.
 161          * In this case dev->parent is NULL.
 162          */
 163         if (parent)
 164                 put_device(parent);
 165         kfree(shost);
 166 }
 167
 168 /**
 169  * scsi_host_alloc - register a scsi host adapter instance.
 170  * @sht:        pointer to scsi host template
 171  * @privsize:   extra bytes to allocate for driver
 172  *
 173  * Note:
 174  *      Allocate a new Scsi_Host and perform basic initialization.
 175  *      The host is not published to the scsi midlayer until scsi_add_host
 176  *      is called.
 177  *
 178  * Return value:
 179  *      Pointer to a new Scsi_Host
 180  **/
 181 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 182 {
 183         struct Scsi_Host *shost;
 184         int gfp_mask = GFP_KERNEL, rval;
 185         DECLARE_COMPLETION(complete);
 186
 187         if (sht->unchecked_isa_dma && privsize)
 188                 gfp_mask |= __GFP_DMA;
 189
 190         /* Check to see if this host has any error handling facilities */
 191         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 192             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 193             !sht->eh_host_reset_handler) {
 194                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 195                                 "ERROR: This is not a safe way to run your "
 196                                         "SCSI host\n"
 197                                 "ERROR: The error handling must be added to "
 198                                 "this driver\n", sht->proc_name);
 199                 dump_stack();
 200         }
 201
 202         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 203         if (!shost)
 204                 return NULL;
 205         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 206
 207         spin_lock_init(&shost->default_lock);
 208         scsi_assign_lock(shost, &shost->default_lock);
 209         INIT_LIST_HEAD(&shost->__devices);
 210         INIT_LIST_HEAD(&shost->eh_cmd_q);
 211         INIT_LIST_HEAD(&shost->starved_list);
 212         init_waitqueue_head(&shost->host_wait);
 213
 214         init_MUTEX(&shost->scan_mutex);
 215
 216         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 217         shost->dma_channel = 0xff;
 218
 219         /* These three are default values which can be overridden */
 220         shost->max_channel = 0;
 221         shost->max_id = 8;
 222         shost->max_lun = 8;
 223
 224         /* Give each shost a default transportt if the driver
 225          * doesn't yet support Transport Attributes */
 226         if (!shost->transportt)
 227                 shost->transportt = &blank_transport_template;
 228
 229         /*
 230          * All drivers right now should be able to handle 12 byte
 231          * commands.  Every so often there are requests for 16 byte
 232          * commands, but individual low-level drivers need to certify that
 233          * they actually do something sensible with such commands.
 234          */
 235         shost->max_cmd_len = 12;
 236         shost->hostt = sht;
 237         shost->this_id = sht->this_id;
 238         shost->can_queue = sht->can_queue;
 239         shost->sg_tablesize = sht->sg_tablesize;
 240         shost->cmd_per_lun = sht->cmd_per_lun;
 241         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 242         shost->use_clustering = sht->use_clustering;
 243
 244         if (sht->max_host_blocked)
 245                 shost->max_host_blocked = sht->max_host_blocked;
 246         else
 247                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 248
 249         /*
 250          * If the driver imposes no hard sector transfer limit, start at
 251          * machine infinity initially.
 252          */
 253         if (sht->max_sectors)
 254                 shost->max_sectors = sht->max_sectors;
 255         else
 256                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 257
 258         /*
 259          * assume a 4GB boundary, if not set
 260          */
 261         if (sht->dma_boundary)
 262                 shost->dma_boundary = sht->dma_boundary;
 263         else
 264                 shost->dma_boundary = 0xffffffff;
 265
 266         rval = scsi_setup_command_freelist(shost);
 267         if (rval)
 268                 goto fail_kfree;
 269
 270         device_initialize(&shost->shost_gendev);
 271         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 272                 shost->host_no);
 273         shost->shost_gendev.release = scsi_host_dev_release;
 274
 275         class_device_initialize(&shost->shost_classdev);
 276         shost->shost_classdev.dev = &shost->shost_gendev;
 277         shost->shost_classdev.class = &shost_class;
 278         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 279                   shost->host_no);
 280
 281         shost->eh_notify = &complete;
 282         rval = kernel_thread(scsi_error_handler, shost, 0);
 283         if (rval < 0)
 284                 goto fail_destroy_freelist;
 285         wait_for_completion(&complete);
 286         shost->eh_notify = NULL;
 287         scsi_proc_hostdir_add(shost->hostt);
 288         return shost;
 289
 290  fail_destroy_freelist:
 291         scsi_destroy_command_freelist(shost);
 292  fail_kfree:
 293         kfree(shost);
 294         return NULL;
 295 }
 296
 297 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 298 {
 299         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 300
 301         if (!sht->detect) {
 302                 printk(KERN_WARNING "scsi_register() called on new-style "
 303                                     "template for driver %s\n", sht->name);
 304                 dump_stack();
 305         }
 306
 307         if (shost)
 308                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 309         return shost;
 310 }
 311
 312 void scsi_unregister(struct Scsi_Host *shost)
 313 {
 314         list_del(&shost->sht_legacy_list);
 315         scsi_host_put(shost);
 316 }
 317
 318 /**
 319  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 320  *
 321  * @hostnum:    host number to locate
 322  *
 323  * Return value:
 324  *      A pointer to located Scsi_Host or NULL.
 325  **/
 326 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 327 {
 328         struct class *class = &shost_class;
 329         struct class_device *cdev;
 330         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 331
 332         down_read(&class->subsys.rwsem);
 333         list_for_each_entry(cdev, &class->children, node) {
 334                 p = class_to_shost(cdev);
 335                 if (p->host_no == hostnum) {
 336                         shost = scsi_host_get(p);
 337                         break;
 338                 }
 339         }
 340         up_read(&class->subsys.rwsem);
 341
 342         return shost;
 343 }
 344
 345 /**
 346  * scsi_host_get - inc a Scsi_Host ref count
 347  * @shost:      Pointer to Scsi_Host to inc.
 348  **/
 349 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 350 {
 351         if (test_bit(SHOST_DEL, &shost->shost_state) ||
 352                 !get_device(&shost->shost_gendev))
 353                 return NULL;
 354         return shost;
 355 }
 356
 357 /**
 358  * scsi_host_put - dec a Scsi_Host ref count
 359  * @shost:      Pointer to Scsi_Host to dec.
 360  **/
 361 void scsi_host_put(struct Scsi_Host *shost)
 362 {
 363         put_device(&shost->shost_gendev);
 364 }
 365
 366 int scsi_init_hosts(void)
 367 {
 368         return class_register(&shost_class);
 369 }
 370
 371 void scsi_exit_hosts(void)
 372 {
 373         class_unregister(&shost_class);
 374 }