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", "TP9",                  "rdac", },
  62         {"SGI", "IS",                   "rdac", },
  63         {"STK", "OPENstorage",          "rdac", },
  64         {"STK", "FLEXLINE 380",         "rdac", },
  65         {"STK", "BladeCtlr",            "rdac", },
  66         {"SUN", "CSM",                  "rdac", },
  67         {"SUN", "LCSM100",              "rdac", },
  68         {"SUN", "STK6580_6780",         "rdac", },
  69         {"SUN", "SUN_6180",             "rdac", },
  70         {"SUN", "ArrayStorage",         "rdac", },
  71         {"DELL", "MD3",                 "rdac", },
  72         {"NETAPP", "INF-01-00",         "rdac", },
  73         {"LSI", "INF-01-00",            "rdac", },
  74         {"ENGENIO", "INF-01-00",        "rdac", },
  75         {NULL, NULL,                    NULL },
  76 };
  77
  78 static const char *
  79 scsi_dh_find_driver(struct scsi_device *sdev)
  80 {
  81         const struct scsi_dh_blist *b;
  82
  83         if (scsi_device_tpgs(sdev))
  84                 return "alua";
  85
  86         for (b = scsi_dh_blist; b->vendor; b++) {
  87                 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
  88                     !strncmp(sdev->model, b->model, strlen(b->model))) {
  89                         return b->driver;
  90                 }
  91         }
  92         return NULL;
  93 }
  94
  95
  96 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
  97 {
  98         struct scsi_device_handler *tmp, *found = NULL;
  99
 100         spin_lock(&list_lock);
 101         list_for_each_entry(tmp, &scsi_dh_list, list) {
 102                 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
 103                         found = tmp;
 104                         break;
 105                 }
 106         }
 107         spin_unlock(&list_lock);
 108         return found;
 109 }
 110
 111 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 112 {
 113         struct scsi_device_handler *dh;
 114
 115         dh = __scsi_dh_lookup(name);
 116         if (!dh) {
 117                 request_module("scsi_dh_%s", name);
 118                 dh = __scsi_dh_lookup(name);
 119         }
 120
 121         return dh;
 122 }
 123
 124 /*
 125  * scsi_dh_handler_attach - Attach a device handler to a device
 126  * @sdev - SCSI device the device handler should attach to
 127  * @scsi_dh - The device handler to attach
 128  */
 129 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 130                                   struct scsi_device_handler *scsi_dh)
 131 {
 132         int error, ret = 0;
 133
 134         if (!try_module_get(scsi_dh->module))
 135                 return -EINVAL;
 136
 137         error = scsi_dh->attach(sdev);
 138         if (error != SCSI_DH_OK) {
 139                 switch (error) {
 140                 case SCSI_DH_NOMEM:
 141                         ret = -ENOMEM;
 142                         break;
 143                 case SCSI_DH_RES_TEMP_UNAVAIL:
 144                         ret = -EAGAIN;
 145                         break;
 146                 case SCSI_DH_DEV_UNSUPP:
 147                 case SCSI_DH_NOSYS:
 148                         ret = -ENODEV;
 149                         break;
 150                 default:
 151                         ret = -EINVAL;
 152                         break;
 153                 }
 154                 if (ret != -ENODEV)
 155                         sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 156                                     scsi_dh->name, error);
 157                 module_put(scsi_dh->module);
 158         } else
 159                 sdev->handler = scsi_dh;
 160
 161         return ret;
 162 }
 163
 164 /*
 165  * scsi_dh_handler_detach - Detach a device handler from a device
 166  * @sdev - SCSI device the device handler should be detached from
 167  */
 168 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 169 {
 170         sdev->handler->detach(sdev);
 171         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 172         module_put(sdev->handler->module);
 173 }
 174
 175 void scsi_dh_add_device(struct scsi_device *sdev)
 176 {
 177         struct scsi_device_handler *devinfo = NULL;
 178         const char *drv;
 179
 180         drv = scsi_dh_find_driver(sdev);
 181         if (drv)
 182                 devinfo = __scsi_dh_lookup(drv);
 183         /*
 184          * device_handler is optional, so ignore errors
 185          * from scsi_dh_handler_attach()
 186          */
 187         if (devinfo)
 188                 (void)scsi_dh_handler_attach(sdev, devinfo);
 189 }
 190
 191 void scsi_dh_release_device(struct scsi_device *sdev)
 192 {
 193         if (sdev->handler)
 194                 scsi_dh_handler_detach(sdev);
 195 }
 196
 197 /*
 198  * scsi_register_device_handler - register a device handler personality
 199  *      module.
 200  * @scsi_dh - device handler to be registered.
 201  *
 202  * Returns 0 on success, -EBUSY if handler already registered.
 203  */
 204 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 205 {
 206         if (__scsi_dh_lookup(scsi_dh->name))
 207                 return -EBUSY;
 208
 209         if (!scsi_dh->attach || !scsi_dh->detach)
 210                 return -EINVAL;
 211
 212         spin_lock(&list_lock);
 213         list_add(&scsi_dh->list, &scsi_dh_list);
 214         spin_unlock(&list_lock);
 215
 216         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 217
 218         return SCSI_DH_OK;
 219 }
 220 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 221
 222 /*
 223  * scsi_unregister_device_handler - register a device handler personality
 224  *      module.
 225  * @scsi_dh - device handler to be unregistered.
 226  *
 227  * Returns 0 on success, -ENODEV if handler not registered.
 228  */
 229 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 230 {
 231         if (!__scsi_dh_lookup(scsi_dh->name))
 232                 return -ENODEV;
 233
 234         spin_lock(&list_lock);
 235         list_del(&scsi_dh->list);
 236         spin_unlock(&list_lock);
 237         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 238
 239         return SCSI_DH_OK;
 240 }
 241 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 242
 243 /*
 244  * scsi_dh_activate - activate the path associated with the scsi_device
 245  *      corresponding to the given request queue.
 246  *     Returns immediately without waiting for activation to be completed.
 247  * @q    - Request queue that is associated with the scsi_device to be
 248  *         activated.
 249  * @fn   - Function to be called upon completion of the activation.
 250  *         Function fn is called with data (below) and the error code.
 251  *         Function fn may be called from the same calling context. So,
 252  *         do not hold the lock in the caller which may be needed in fn.
 253  * @data - data passed to the function fn upon completion.
 254  *
 255  */
 256 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 257 {
 258         struct scsi_device *sdev;
 259         int err = SCSI_DH_NOSYS;
 260
 261         sdev = scsi_device_from_queue(q);
 262         if (!sdev) {
 263                 if (fn)
 264                         fn(data, err);
 265                 return err;
 266         }
 267
 268         if (!sdev->handler)
 269                 goto out_fn;
 270         err = SCSI_DH_NOTCONN;
 271         if (sdev->sdev_state == SDEV_CANCEL ||
 272             sdev->sdev_state == SDEV_DEL)
 273                 goto out_fn;
 274
 275         err = SCSI_DH_DEV_OFFLINED;
 276         if (sdev->sdev_state == SDEV_OFFLINE)
 277                 goto out_fn;
 278
 279         if (sdev->handler->activate)
 280                 err = sdev->handler->activate(sdev, fn, data);
 281
 282 out_put_device:
 283         put_device(&sdev->sdev_gendev);
 284         return err;
 285
 286 out_fn:
 287         if (fn)
 288                 fn(data, err);
 289         goto out_put_device;
 290 }
 291 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 292
 293 /*
 294  * scsi_dh_set_params - set the parameters for the device as per the
 295  *      string specified in params.
 296  * @q - Request queue that is associated with the scsi_device for
 297  *      which the parameters to be set.
 298  * @params - parameters in the following format
 299  *      "no_of_params\0param1\0param2\0param3\0...\0"
 300  *      for example, string for 2 parameters with value 10 and 21
 301  *      is specified as "2\010\021\0".
 302  */
 303 int scsi_dh_set_params(struct request_queue *q, const char *params)
 304 {
 305         struct scsi_device *sdev;
 306         int err = -SCSI_DH_NOSYS;
 307
 308         sdev = scsi_device_from_queue(q);
 309         if (!sdev)
 310                 return err;
 311
 312         if (sdev->handler && sdev->handler->set_params)
 313                 err = sdev->handler->set_params(sdev, params);
 314         put_device(&sdev->sdev_gendev);
 315         return err;
 316 }
 317 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 318
 319 /*
 320  * scsi_dh_attach - Attach device handler
 321  * @q - Request queue that is associated with the scsi_device
 322  *      the handler should be attached to
 323  * @name - name of the handler to attach
 324  */
 325 int scsi_dh_attach(struct request_queue *q, const char *name)
 326 {
 327         struct scsi_device *sdev;
 328         struct scsi_device_handler *scsi_dh;
 329         int err = 0;
 330
 331         sdev = scsi_device_from_queue(q);
 332         if (!sdev)
 333                 return -ENODEV;
 334
 335         scsi_dh = scsi_dh_lookup(name);
 336         if (!scsi_dh) {
 337                 err = -EINVAL;
 338                 goto out_put_device;
 339         }
 340
 341         if (sdev->handler) {
 342                 if (sdev->handler != scsi_dh)
 343                         err = -EBUSY;
 344                 goto out_put_device;
 345         }
 346
 347         err = scsi_dh_handler_attach(sdev, scsi_dh);
 348
 349 out_put_device:
 350         put_device(&sdev->sdev_gendev);
 351         return err;
 352 }
 353 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 354
 355 /*
 356  * scsi_dh_attached_handler_name - Get attached device handler's name
 357  * @q - Request queue that is associated with the scsi_device
 358  *      that may have a device handler attached
 359  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 360  *
 361  * Returns name of attached handler, NULL if no handler is attached.
 362  * Caller must take care to free the returned string.
 363  */
 364 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 365 {
 366         struct scsi_device *sdev;
 367         const char *handler_name = NULL;
 368
 369         sdev = scsi_device_from_queue(q);
 370         if (!sdev)
 371                 return NULL;
 372
 373         if (sdev->handler)
 374                 handler_name = kstrdup(sdev->handler->name, gfp);
 375         put_device(&sdev->sdev_gendev);
 376         return handler_name;
 377 }
 378 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);