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