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         {"IBM", "3542",                 "rdac", },
  60         {"IBM", "3552",                 "rdac", },
  61         {"SGI", "TP9300",               "rdac", },
  62         {"SGI", "TP9400",               "rdac", },
  63         {"SGI", "TP9500",               "rdac", },
  64         {"SGI", "TP9700",               "rdac", },
  65         {"SGI", "IS",                   "rdac", },
  66         {"STK", "OPENstorage",          "rdac", },
  67         {"STK", "FLEXLINE 380",         "rdac", },
  68         {"STK", "BladeCtlr",            "rdac", },
  69         {"SUN", "CSM",                  "rdac", },
  70         {"SUN", "LCSM100",              "rdac", },
  71         {"SUN", "STK6580_6780",         "rdac", },
  72         {"SUN", "SUN_6180",             "rdac", },
  73         {"SUN", "ArrayStorage",         "rdac", },
  74         {"DELL", "MD3",                 "rdac", },
  75         {"NETAPP", "INF-01-00",         "rdac", },
  76         {"LSI", "INF-01-00",            "rdac", },
  77         {"ENGENIO", "INF-01-00",        "rdac", },
  78         {NULL, NULL,                    NULL },
  79 };
  80
  81 static const char *
  82 scsi_dh_find_driver(struct scsi_device *sdev)
  83 {
  84         const struct scsi_dh_blist *b;
  85
  86         if (scsi_device_tpgs(sdev))
  87                 return "alua";
  88
  89         for (b = scsi_dh_blist; b->vendor; b++) {
  90                 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
  91                     !strncmp(sdev->model, b->model, strlen(b->model))) {
  92                         return b->driver;
  93                 }
  94         }
  95         return NULL;
  96 }
  97
  98
  99 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
 100 {
 101         struct scsi_device_handler *tmp, *found = NULL;
 102
 103         spin_lock(&list_lock);
 104         list_for_each_entry(tmp, &scsi_dh_list, list) {
 105                 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
 106                         found = tmp;
 107                         break;
 108                 }
 109         }
 110         spin_unlock(&list_lock);
 111         return found;
 112 }
 113
 114 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 115 {
 116         struct scsi_device_handler *dh;
 117
 118         if (!name || strlen(name) == 0)
 119                 return NULL;
 120
 121         dh = __scsi_dh_lookup(name);
 122         if (!dh) {
 123                 request_module("scsi_dh_%s", name);
 124                 dh = __scsi_dh_lookup(name);
 125         }
 126
 127         return dh;
 128 }
 129
 130 /*
 131  * scsi_dh_handler_attach - Attach a device handler to a device
 132  * @sdev - SCSI device the device handler should attach to
 133  * @scsi_dh - The device handler to attach
 134  */
 135 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 136                                   struct scsi_device_handler *scsi_dh)
 137 {
 138         int error, ret = 0;
 139
 140         if (!try_module_get(scsi_dh->module))
 141                 return -EINVAL;
 142
 143         error = scsi_dh->attach(sdev);
 144         if (error != SCSI_DH_OK) {
 145                 switch (error) {
 146                 case SCSI_DH_NOMEM:
 147                         ret = -ENOMEM;
 148                         break;
 149                 case SCSI_DH_RES_TEMP_UNAVAIL:
 150                         ret = -EAGAIN;
 151                         break;
 152                 case SCSI_DH_DEV_UNSUPP:
 153                 case SCSI_DH_NOSYS:
 154                         ret = -ENODEV;
 155                         break;
 156                 default:
 157                         ret = -EINVAL;
 158                         break;
 159                 }
 160                 if (ret != -ENODEV)
 161                         sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 162                                     scsi_dh->name, error);
 163                 module_put(scsi_dh->module);
 164         } else
 165                 sdev->handler = scsi_dh;
 166
 167         return ret;
 168 }
 169
 170 /*
 171  * scsi_dh_handler_detach - Detach a device handler from a device
 172  * @sdev - SCSI device the device handler should be detached from
 173  */
 174 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 175 {
 176         sdev->handler->detach(sdev);
 177         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 178         module_put(sdev->handler->module);
 179 }
 180
 181 void scsi_dh_add_device(struct scsi_device *sdev)
 182 {
 183         struct scsi_device_handler *devinfo = NULL;
 184         const char *drv;
 185
 186         drv = scsi_dh_find_driver(sdev);
 187         if (drv)
 188                 devinfo = __scsi_dh_lookup(drv);
 189         /*
 190          * device_handler is optional, so ignore errors
 191          * from scsi_dh_handler_attach()
 192          */
 193         if (devinfo)
 194                 (void)scsi_dh_handler_attach(sdev, devinfo);
 195 }
 196
 197 void scsi_dh_release_device(struct scsi_device *sdev)
 198 {
 199         if (sdev->handler)
 200                 scsi_dh_handler_detach(sdev);
 201 }
 202
 203 /*
 204  * scsi_register_device_handler - register a device handler personality
 205  *      module.
 206  * @scsi_dh - device handler to be registered.
 207  *
 208  * Returns 0 on success, -EBUSY if handler already registered.
 209  */
 210 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 211 {
 212         if (__scsi_dh_lookup(scsi_dh->name))
 213                 return -EBUSY;
 214
 215         if (!scsi_dh->attach || !scsi_dh->detach)
 216                 return -EINVAL;
 217
 218         spin_lock(&list_lock);
 219         list_add(&scsi_dh->list, &scsi_dh_list);
 220         spin_unlock(&list_lock);
 221
 222         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 223
 224         return SCSI_DH_OK;
 225 }
 226 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 227
 228 /*
 229  * scsi_unregister_device_handler - register a device handler personality
 230  *      module.
 231  * @scsi_dh - device handler to be unregistered.
 232  *
 233  * Returns 0 on success, -ENODEV if handler not registered.
 234  */
 235 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 236 {
 237         if (!__scsi_dh_lookup(scsi_dh->name))
 238                 return -ENODEV;
 239
 240         spin_lock(&list_lock);
 241         list_del(&scsi_dh->list);
 242         spin_unlock(&list_lock);
 243         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 244
 245         return SCSI_DH_OK;
 246 }
 247 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 248
 249 /*
 250  * scsi_dh_activate - activate the path associated with the scsi_device
 251  *      corresponding to the given request queue.
 252  *     Returns immediately without waiting for activation to be completed.
 253  * @q    - Request queue that is associated with the scsi_device to be
 254  *         activated.
 255  * @fn   - Function to be called upon completion of the activation.
 256  *         Function fn is called with data (below) and the error code.
 257  *         Function fn may be called from the same calling context. So,
 258  *         do not hold the lock in the caller which may be needed in fn.
 259  * @data - data passed to the function fn upon completion.
 260  *
 261  */
 262 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 263 {
 264         struct scsi_device *sdev;
 265         int err = SCSI_DH_NOSYS;
 266
 267         sdev = scsi_device_from_queue(q);
 268         if (!sdev) {
 269                 if (fn)
 270                         fn(data, err);
 271                 return err;
 272         }
 273
 274         if (!sdev->handler)
 275                 goto out_fn;
 276         err = SCSI_DH_NOTCONN;
 277         if (sdev->sdev_state == SDEV_CANCEL ||
 278             sdev->sdev_state == SDEV_DEL)
 279                 goto out_fn;
 280
 281         err = SCSI_DH_DEV_OFFLINED;
 282         if (sdev->sdev_state == SDEV_OFFLINE)
 283                 goto out_fn;
 284
 285         if (sdev->handler->activate)
 286                 err = sdev->handler->activate(sdev, fn, data);
 287
 288 out_put_device:
 289         put_device(&sdev->sdev_gendev);
 290         return err;
 291
 292 out_fn:
 293         if (fn)
 294                 fn(data, err);
 295         goto out_put_device;
 296 }
 297 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 298
 299 /*
 300  * scsi_dh_set_params - set the parameters for the device as per the
 301  *      string specified in params.
 302  * @q - Request queue that is associated with the scsi_device for
 303  *      which the parameters to be set.
 304  * @params - parameters in the following format
 305  *      "no_of_params\0param1\0param2\0param3\0...\0"
 306  *      for example, string for 2 parameters with value 10 and 21
 307  *      is specified as "2\010\021\0".
 308  */
 309 int scsi_dh_set_params(struct request_queue *q, const char *params)
 310 {
 311         struct scsi_device *sdev;
 312         int err = -SCSI_DH_NOSYS;
 313
 314         sdev = scsi_device_from_queue(q);
 315         if (!sdev)
 316                 return err;
 317
 318         if (sdev->handler && sdev->handler->set_params)
 319                 err = sdev->handler->set_params(sdev, params);
 320         put_device(&sdev->sdev_gendev);
 321         return err;
 322 }
 323 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 324
 325 /*
 326  * scsi_dh_attach - Attach device handler
 327  * @q - Request queue that is associated with the scsi_device
 328  *      the handler should be attached to
 329  * @name - name of the handler to attach
 330  */
 331 int scsi_dh_attach(struct request_queue *q, const char *name)
 332 {
 333         struct scsi_device *sdev;
 334         struct scsi_device_handler *scsi_dh;
 335         int err = 0;
 336
 337         sdev = scsi_device_from_queue(q);
 338         if (!sdev)
 339                 return -ENODEV;
 340
 341         scsi_dh = scsi_dh_lookup(name);
 342         if (!scsi_dh) {
 343                 err = -EINVAL;
 344                 goto out_put_device;
 345         }
 346
 347         if (sdev->handler) {
 348                 if (sdev->handler != scsi_dh)
 349                         err = -EBUSY;
 350                 goto out_put_device;
 351         }
 352
 353         err = scsi_dh_handler_attach(sdev, scsi_dh);
 354
 355 out_put_device:
 356         put_device(&sdev->sdev_gendev);
 357         return err;
 358 }
 359 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 360
 361 /*
 362  * scsi_dh_attached_handler_name - Get attached device handler's name
 363  * @q - Request queue that is associated with the scsi_device
 364  *      that may have a device handler attached
 365  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 366  *
 367  * Returns name of attached handler, NULL if no handler is attached.
 368  * Caller must take care to free the returned string.
 369  */
 370 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 371 {
 372         struct scsi_device *sdev;
 373         const char *handler_name = NULL;
 374
 375         sdev = scsi_device_from_queue(q);
 376         if (!sdev)
 377                 return NULL;
 378
 379         if (sdev->handler)
 380                 handler_name = kstrdup(sdev->handler->name, gfp);
 381         put_device(&sdev->sdev_gendev);
 382         return handler_name;
 383 }
 384 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);