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",                 "clariion" },
  40         {"DGC", "DISK",                 "clariion" },
  41         {"DGC", "VRAID",                "clariion" },
  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 /*
 157  * Functions for sysfs attribute 'dh_state'
 158  */
 159 static ssize_t
 160 store_dh_state(struct device *dev, struct device_attribute *attr,
 161                const char *buf, size_t count)
 162 {
 163         struct scsi_device *sdev = to_scsi_device(dev);
 164         struct scsi_device_handler *scsi_dh;
 165         int err = -EINVAL;
 166
 167         if (sdev->sdev_state == SDEV_CANCEL ||
 168             sdev->sdev_state == SDEV_DEL)
 169                 return -ENODEV;
 170
 171         if (!sdev->handler) {
 172                 /*
 173                  * Attach to a device handler
 174                  */
 175                 scsi_dh = scsi_dh_lookup(buf);
 176                 if (!scsi_dh)
 177                         return err;
 178                 err = scsi_dh_handler_attach(sdev, scsi_dh);
 179         } else {
 180                 if (!strncmp(buf, "detach", 6)) {
 181                         /*
 182                          * Detach from a device handler
 183                          */
 184                         sdev_printk(KERN_WARNING, sdev,
 185                                     "can't detach handler %s.\n",
 186                                     sdev->handler->name);
 187                         err = -EINVAL;
 188                 } else if (!strncmp(buf, "activate", 8)) {
 189                         /*
 190                          * Activate a device handler
 191                          */
 192                         if (sdev->handler->activate)
 193                                 err = sdev->handler->activate(sdev, NULL, NULL);
 194                         else
 195                                 err = 0;
 196                 }
 197         }
 198
 199         return err<0?err:count;
 200 }
 201
 202 static ssize_t
 203 show_dh_state(struct device *dev, struct device_attribute *attr, char *buf)
 204 {
 205         struct scsi_device *sdev = to_scsi_device(dev);
 206
 207         if (!sdev->handler)
 208                 return snprintf(buf, 20, "detached\n");
 209
 210         return snprintf(buf, 20, "%s\n", sdev->handler->name);
 211 }
 212
 213 static struct device_attribute scsi_dh_state_attr =
 214         __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
 215                store_dh_state);
 216
 217 int scsi_dh_add_device(struct scsi_device *sdev)
 218 {
 219         struct scsi_device_handler *devinfo = NULL;
 220         const char *drv;
 221         int err;
 222
 223         err = device_create_file(&sdev->sdev_gendev, &scsi_dh_state_attr);
 224         if (err)
 225                 return err;
 226
 227         drv = scsi_dh_find_driver(sdev);
 228         if (drv)
 229                 devinfo = __scsi_dh_lookup(drv);
 230         if (devinfo)
 231                 err = scsi_dh_handler_attach(sdev, devinfo);
 232         return err;
 233 }
 234
 235 void scsi_dh_release_device(struct scsi_device *sdev)
 236 {
 237         if (sdev->handler)
 238                 scsi_dh_handler_detach(sdev);
 239 }
 240
 241 void scsi_dh_remove_device(struct scsi_device *sdev)
 242 {
 243         device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr);
 244 }
 245
 246 /*
 247  * scsi_register_device_handler - register a device handler personality
 248  *      module.
 249  * @scsi_dh - device handler to be registered.
 250  *
 251  * Returns 0 on success, -EBUSY if handler already registered.
 252  */
 253 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 254 {
 255         if (__scsi_dh_lookup(scsi_dh->name))
 256                 return -EBUSY;
 257
 258         if (!scsi_dh->attach || !scsi_dh->detach)
 259                 return -EINVAL;
 260
 261         spin_lock(&list_lock);
 262         list_add(&scsi_dh->list, &scsi_dh_list);
 263         spin_unlock(&list_lock);
 264
 265         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 266
 267         return SCSI_DH_OK;
 268 }
 269 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 270
 271 /*
 272  * scsi_unregister_device_handler - register a device handler personality
 273  *      module.
 274  * @scsi_dh - device handler to be unregistered.
 275  *
 276  * Returns 0 on success, -ENODEV if handler not registered.
 277  */
 278 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 279 {
 280         if (!__scsi_dh_lookup(scsi_dh->name))
 281                 return -ENODEV;
 282
 283         spin_lock(&list_lock);
 284         list_del(&scsi_dh->list);
 285         spin_unlock(&list_lock);
 286         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 287
 288         return SCSI_DH_OK;
 289 }
 290 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 291
 292 static struct scsi_device *get_sdev_from_queue(struct request_queue *q)
 293 {
 294         struct scsi_device *sdev;
 295         unsigned long flags;
 296
 297         spin_lock_irqsave(q->queue_lock, flags);
 298         sdev = q->queuedata;
 299         if (!sdev || !get_device(&sdev->sdev_gendev))
 300                 sdev = NULL;
 301         spin_unlock_irqrestore(q->queue_lock, flags);
 302
 303         return sdev;
 304 }
 305
 306 /*
 307  * scsi_dh_activate - activate the path associated with the scsi_device
 308  *      corresponding to the given request queue.
 309  *     Returns immediately without waiting for activation to be completed.
 310  * @q    - Request queue that is associated with the scsi_device to be
 311  *         activated.
 312  * @fn   - Function to be called upon completion of the activation.
 313  *         Function fn is called with data (below) and the error code.
 314  *         Function fn may be called from the same calling context. So,
 315  *         do not hold the lock in the caller which may be needed in fn.
 316  * @data - data passed to the function fn upon completion.
 317  *
 318  */
 319 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 320 {
 321         struct scsi_device *sdev;
 322         int err = SCSI_DH_NOSYS;
 323
 324         sdev = get_sdev_from_queue(q);
 325         if (!sdev) {
 326                 if (fn)
 327                         fn(data, err);
 328                 return err;
 329         }
 330
 331         if (!sdev->handler)
 332                 goto out_fn;
 333         err = SCSI_DH_NOTCONN;
 334         if (sdev->sdev_state == SDEV_CANCEL ||
 335             sdev->sdev_state == SDEV_DEL)
 336                 goto out_fn;
 337
 338         err = SCSI_DH_DEV_OFFLINED;
 339         if (sdev->sdev_state == SDEV_OFFLINE)
 340                 goto out_fn;
 341
 342         if (sdev->handler->activate)
 343                 err = sdev->handler->activate(sdev, fn, data);
 344
 345 out_put_device:
 346         put_device(&sdev->sdev_gendev);
 347         return err;
 348
 349 out_fn:
 350         if (fn)
 351                 fn(data, err);
 352         goto out_put_device;
 353 }
 354 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 355
 356 /*
 357  * scsi_dh_set_params - set the parameters for the device as per the
 358  *      string specified in params.
 359  * @q - Request queue that is associated with the scsi_device for
 360  *      which the parameters to be set.
 361  * @params - parameters in the following format
 362  *      "no_of_params\0param1\0param2\0param3\0...\0"
 363  *      for example, string for 2 parameters with value 10 and 21
 364  *      is specified as "2\010\021\0".
 365  */
 366 int scsi_dh_set_params(struct request_queue *q, const char *params)
 367 {
 368         struct scsi_device *sdev;
 369         int err = -SCSI_DH_NOSYS;
 370
 371         sdev = get_sdev_from_queue(q);
 372         if (!sdev)
 373                 return err;
 374
 375         if (sdev->handler && sdev->handler->set_params)
 376                 err = sdev->handler->set_params(sdev, params);
 377         put_device(&sdev->sdev_gendev);
 378         return err;
 379 }
 380 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 381
 382 /*
 383  * scsi_dh_attach - Attach device handler
 384  * @q - Request queue that is associated with the scsi_device
 385  *      the handler should be attached to
 386  * @name - name of the handler to attach
 387  */
 388 int scsi_dh_attach(struct request_queue *q, const char *name)
 389 {
 390         struct scsi_device *sdev;
 391         struct scsi_device_handler *scsi_dh;
 392         int err = 0;
 393
 394         sdev = get_sdev_from_queue(q);
 395         if (!sdev)
 396                 return -ENODEV;
 397
 398         scsi_dh = scsi_dh_lookup(name);
 399         if (!scsi_dh) {
 400                 err = -EINVAL;
 401                 goto out_put_device;
 402         }
 403
 404         if (sdev->handler) {
 405                 if (sdev->handler != scsi_dh)
 406                         err = -EBUSY;
 407                 goto out_put_device;
 408         }
 409
 410         err = scsi_dh_handler_attach(sdev, scsi_dh);
 411
 412 out_put_device:
 413         put_device(&sdev->sdev_gendev);
 414         return err;
 415 }
 416 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 417
 418 /*
 419  * scsi_dh_attached_handler_name - Get attached device handler's name
 420  * @q - Request queue that is associated with the scsi_device
 421  *      that may have a device handler attached
 422  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 423  *
 424  * Returns name of attached handler, NULL if no handler is attached.
 425  * Caller must take care to free the returned string.
 426  */
 427 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 428 {
 429         struct scsi_device *sdev;
 430         const char *handler_name = NULL;
 431
 432         sdev = get_sdev_from_queue(q);
 433         if (!sdev)
 434                 return NULL;
 435
 436         if (sdev->handler)
 437                 handler_name = kstrdup(sdev->handler->name, gfp);
 438         put_device(&sdev->sdev_gendev);
 439         return handler_name;
 440 }
 441 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);