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