drivers/scsi/scsi_dh.c

   1 /*
   2  * SCSI device handler infrastruture.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright IBM Corporation, 2007
  19  *      Authors:
  20  *               Chandra Seetharaman <sekharan@us.ibm.com>
  21  *               Mike Anderson <andmike@linux.vnet.ibm.com>
  22  */
  23
  24 #include <linux/slab.h>
  25 #include <linux/module.h>
  26 #include <scsi/scsi_dh.h>
  27 #include "scsi_priv.h"
  28
  29 static DEFINE_SPINLOCK(list_lock);
  30 static LIST_HEAD(scsi_dh_list);
  31
  32 struct scsi_dh_blist {
  33         const char *vendor;
  34         const char *model;
  35         const char *driver;
  36 };
  37
  38 static const struct scsi_dh_blist scsi_dh_blist[] = {
  39         {"DGC", "RAID",                 "emc" },
  40         {"DGC", "DISK",                 "emc" },
  41         {"DGC", "VRAID",                "emc" },
  42
  43         {"COMPAQ", "MSA1000 VOLUME",    "hp_sw" },
  44         {"COMPAQ", "HSV110",            "hp_sw" },
  45         {"HP", "HSV100",                "hp_sw"},
  46         {"DEC", "HSG80",                "hp_sw"},
  47
  48         {"IBM", "1722",                 "rdac", },
  49         {"IBM", "1724",                 "rdac", },
  50         {"IBM", "1726",                 "rdac", },
  51         {"IBM", "1742",                 "rdac", },
  52         {"IBM", "1745",                 "rdac", },
  53         {"IBM", "1746",                 "rdac", },
  54         {"IBM", "1813",                 "rdac", },
  55         {"IBM", "1814",                 "rdac", },
  56         {"IBM", "1815",                 "rdac", },
  57         {"IBM", "1818",                 "rdac", },
  58         {"IBM", "3526",                 "rdac", },
  59         {"SGI", "TP9",                  "rdac", },
  60         {"SGI", "IS",                   "rdac", },
  61         {"STK", "OPENstorage D280",     "rdac", },
  62         {"STK", "FLEXLINE 380",         "rdac", },
  63         {"SUN", "CSM",                  "rdac", },
  64         {"SUN", "LCSM100",              "rdac", },
  65         {"SUN", "STK6580_6780",         "rdac", },
  66         {"SUN", "SUN_6180",             "rdac", },
  67         {"SUN", "ArrayStorage",         "rdac", },
  68         {"DELL", "MD3",                 "rdac", },
  69         {"NETAPP", "INF-01-00",         "rdac", },
  70         {"LSI", "INF-01-00",            "rdac", },
  71         {"ENGENIO", "INF-01-00",        "rdac", },
  72         {NULL, NULL,                    NULL },
  73 };
  74
  75 static const char *
  76 scsi_dh_find_driver(struct scsi_device *sdev)
  77 {
  78         const struct scsi_dh_blist *b;
  79
  80         if (scsi_device_tpgs(sdev))
  81                 return "alua";
  82
  83         for (b = scsi_dh_blist; b->vendor; b++) {
  84                 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
  85                     !strncmp(sdev->model, b->model, strlen(b->model))) {
  86                         return b->driver;
  87                 }
  88         }
  89         return NULL;
  90 }
  91
  92
  93 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
  94 {
  95         struct scsi_device_handler *tmp, *found = NULL;
  96
  97         spin_lock(&list_lock);
  98         list_for_each_entry(tmp, &scsi_dh_list, list) {
  99                 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
 100                         found = tmp;
 101                         break;
 102                 }
 103         }
 104         spin_unlock(&list_lock);
 105         return found;
 106 }
 107
 108 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 109 {
 110         struct scsi_device_handler *dh;
 111
 112         dh = __scsi_dh_lookup(name);
 113         if (!dh) {
 114                 request_module("scsi_dh_%s", name);
 115                 dh = __scsi_dh_lookup(name);
 116         }
 117
 118         return dh;
 119 }
 120
 121 /*
 122  * scsi_dh_handler_attach - Attach a device handler to a device
 123  * @sdev - SCSI device the device handler should attach to
 124  * @scsi_dh - The device handler to attach
 125  */
 126 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 127                                   struct scsi_device_handler *scsi_dh)
 128 {
 129         int error;
 130
 131         if (!try_module_get(scsi_dh->module))
 132                 return -EINVAL;
 133
 134         error = scsi_dh->attach(sdev);
 135         if (error) {
 136                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 137                             scsi_dh->name, error);
 138                 module_put(scsi_dh->module);
 139         } else
 140                 sdev->handler = scsi_dh;
 141
 142         return error;
 143 }
 144
 145 /*
 146  * scsi_dh_handler_detach - Detach a device handler from a device
 147  * @sdev - SCSI device the device handler should be detached from
 148  */
 149 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 150 {
 151         sdev->handler->detach(sdev);
 152         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 153         module_put(sdev->handler->module);
 154 }
 155
 156 int scsi_dh_add_device(struct scsi_device *sdev)
 157 {
 158         struct scsi_device_handler *devinfo = NULL;
 159         const char *drv;
 160         int err = 0;
 161
 162         drv = scsi_dh_find_driver(sdev);
 163         if (drv)
 164                 devinfo = __scsi_dh_lookup(drv);
 165         if (devinfo)
 166                 err = scsi_dh_handler_attach(sdev, devinfo);
 167         return err;
 168 }
 169
 170 void scsi_dh_release_device(struct scsi_device *sdev)
 171 {
 172         if (sdev->handler)
 173                 scsi_dh_handler_detach(sdev);
 174 }
 175
 176 /*
 177  * scsi_register_device_handler - register a device handler personality
 178  *      module.
 179  * @scsi_dh - device handler to be registered.
 180  *
 181  * Returns 0 on success, -EBUSY if handler already registered.
 182  */
 183 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 184 {
 185         if (__scsi_dh_lookup(scsi_dh->name))
 186                 return -EBUSY;
 187
 188         if (!scsi_dh->attach || !scsi_dh->detach)
 189                 return -EINVAL;
 190
 191         spin_lock(&list_lock);
 192         list_add(&scsi_dh->list, &scsi_dh_list);
 193         spin_unlock(&list_lock);
 194
 195         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 196
 197         return SCSI_DH_OK;
 198 }
 199 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 200
 201 /*
 202  * scsi_unregister_device_handler - register a device handler personality
 203  *      module.
 204  * @scsi_dh - device handler to be unregistered.
 205  *
 206  * Returns 0 on success, -ENODEV if handler not registered.
 207  */
 208 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 209 {
 210         if (!__scsi_dh_lookup(scsi_dh->name))
 211                 return -ENODEV;
 212
 213         spin_lock(&list_lock);
 214         list_del(&scsi_dh->list);
 215         spin_unlock(&list_lock);
 216         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 217
 218         return SCSI_DH_OK;
 219 }
 220 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 221
 222 static struct scsi_device *get_sdev_from_queue(struct request_queue *q)
 223 {
 224         struct scsi_device *sdev;
 225         unsigned long flags;
 226
 227         spin_lock_irqsave(q->queue_lock, flags);
 228         sdev = q->queuedata;
 229         if (!sdev || !get_device(&sdev->sdev_gendev))
 230                 sdev = NULL;
 231         spin_unlock_irqrestore(q->queue_lock, flags);
 232
 233         return sdev;
 234 }
 235
 236 /*
 237  * scsi_dh_activate - activate the path associated with the scsi_device
 238  *      corresponding to the given request queue.
 239  *     Returns immediately without waiting for activation to be completed.
 240  * @q    - Request queue that is associated with the scsi_device to be
 241  *         activated.
 242  * @fn   - Function to be called upon completion of the activation.
 243  *         Function fn is called with data (below) and the error code.
 244  *         Function fn may be called from the same calling context. So,
 245  *         do not hold the lock in the caller which may be needed in fn.
 246  * @data - data passed to the function fn upon completion.
 247  *
 248  */
 249 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 250 {
 251         struct scsi_device *sdev;
 252         int err = SCSI_DH_NOSYS;
 253
 254         sdev = get_sdev_from_queue(q);
 255         if (!sdev) {
 256                 if (fn)
 257                         fn(data, err);
 258                 return err;
 259         }
 260
 261         if (!sdev->handler)
 262                 goto out_fn;
 263         err = SCSI_DH_NOTCONN;
 264         if (sdev->sdev_state == SDEV_CANCEL ||
 265             sdev->sdev_state == SDEV_DEL)
 266                 goto out_fn;
 267
 268         err = SCSI_DH_DEV_OFFLINED;
 269         if (sdev->sdev_state == SDEV_OFFLINE)
 270                 goto out_fn;
 271
 272         if (sdev->handler->activate)
 273                 err = sdev->handler->activate(sdev, fn, data);
 274
 275 out_put_device:
 276         put_device(&sdev->sdev_gendev);
 277         return err;
 278
 279 out_fn:
 280         if (fn)
 281                 fn(data, err);
 282         goto out_put_device;
 283 }
 284 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 285
 286 /*
 287  * scsi_dh_set_params - set the parameters for the device as per the
 288  *      string specified in params.
 289  * @q - Request queue that is associated with the scsi_device for
 290  *      which the parameters to be set.
 291  * @params - parameters in the following format
 292  *      "no_of_params\0param1\0param2\0param3\0...\0"
 293  *      for example, string for 2 parameters with value 10 and 21
 294  *      is specified as "2\010\021\0".
 295  */
 296 int scsi_dh_set_params(struct request_queue *q, const char *params)
 297 {
 298         struct scsi_device *sdev;
 299         int err = -SCSI_DH_NOSYS;
 300
 301         sdev = get_sdev_from_queue(q);
 302         if (!sdev)
 303                 return err;
 304
 305         if (sdev->handler && sdev->handler->set_params)
 306                 err = sdev->handler->set_params(sdev, params);
 307         put_device(&sdev->sdev_gendev);
 308         return err;
 309 }
 310 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 311
 312 /*
 313  * scsi_dh_attach - Attach device handler
 314  * @q - Request queue that is associated with the scsi_device
 315  *      the handler should be attached to
 316  * @name - name of the handler to attach
 317  */
 318 int scsi_dh_attach(struct request_queue *q, const char *name)
 319 {
 320         struct scsi_device *sdev;
 321         struct scsi_device_handler *scsi_dh;
 322         int err = 0;
 323
 324         sdev = get_sdev_from_queue(q);
 325         if (!sdev)
 326                 return -ENODEV;
 327
 328         scsi_dh = scsi_dh_lookup(name);
 329         if (!scsi_dh) {
 330                 err = -EINVAL;
 331                 goto out_put_device;
 332         }
 333
 334         if (sdev->handler) {
 335                 if (sdev->handler != scsi_dh)
 336                         err = -EBUSY;
 337                 goto out_put_device;
 338         }
 339
 340         err = scsi_dh_handler_attach(sdev, scsi_dh);
 341
 342 out_put_device:
 343         put_device(&sdev->sdev_gendev);
 344         return err;
 345 }
 346 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 347
 348 /*
 349  * scsi_dh_attached_handler_name - Get attached device handler's name
 350  * @q - Request queue that is associated with the scsi_device
 351  *      that may have a device handler attached
 352  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 353  *
 354  * Returns name of attached handler, NULL if no handler is attached.
 355  * Caller must take care to free the returned string.
 356  */
 357 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 358 {
 359         struct scsi_device *sdev;
 360         const char *handler_name = NULL;
 361
 362         sdev = get_sdev_from_queue(q);
 363         if (!sdev)
 364                 return NULL;
 365
 366         if (sdev->handler)
 367                 handler_name = kstrdup(sdev->handler->name, gfp);
 368         put_device(&sdev->sdev_gendev);
 369         return handler_name;
 370 }
 371 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);