drivers/scsi/scsi_dh.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * SCSI device handler infrastruture.
   4  *
   5  * Copyright IBM Corporation, 2007
   6  *      Authors:
   7  *               Chandra Seetharaman <sekharan@us.ibm.com>
   8  *               Mike Anderson <andmike@linux.vnet.ibm.com>
   9  */
  10
  11 #include <linux/slab.h>
  12 #include <linux/module.h>
  13 #include <scsi/scsi_dh.h>
  14 #include "scsi_priv.h"
  15
  16 static DEFINE_SPINLOCK(list_lock);
  17 static LIST_HEAD(scsi_dh_list);
  18
  19 struct scsi_dh_blist {
  20         const char *vendor;
  21         const char *model;
  22         const char *driver;
  23 };
  24
  25 static const struct scsi_dh_blist scsi_dh_blist[] = {
  26         {"DGC", "RAID",                 "emc" },
  27         {"DGC", "DISK",                 "emc" },
  28         {"DGC", "VRAID",                "emc" },
  29
  30         {"COMPAQ", "MSA1000 VOLUME",    "hp_sw" },
  31         {"COMPAQ", "HSV110",            "hp_sw" },
  32         {"HP", "HSV100",                "hp_sw"},
  33         {"DEC", "HSG80",                "hp_sw"},
  34
  35         {"IBM", "1722",                 "rdac", },
  36         {"IBM", "1724",                 "rdac", },
  37         {"IBM", "1726",                 "rdac", },
  38         {"IBM", "1742",                 "rdac", },
  39         {"IBM", "1745",                 "rdac", },
  40         {"IBM", "1746",                 "rdac", },
  41         {"IBM", "1813",                 "rdac", },
  42         {"IBM", "1814",                 "rdac", },
  43         {"IBM", "1815",                 "rdac", },
  44         {"IBM", "1818",                 "rdac", },
  45         {"IBM", "3526",                 "rdac", },
  46         {"IBM", "3542",                 "rdac", },
  47         {"IBM", "3552",                 "rdac", },
  48         {"SGI", "TP9300",               "rdac", },
  49         {"SGI", "TP9400",               "rdac", },
  50         {"SGI", "TP9500",               "rdac", },
  51         {"SGI", "TP9700",               "rdac", },
  52         {"SGI", "IS",                   "rdac", },
  53         {"STK", "OPENstorage",          "rdac", },
  54         {"STK", "FLEXLINE 380",         "rdac", },
  55         {"STK", "BladeCtlr",            "rdac", },
  56         {"SUN", "CSM",                  "rdac", },
  57         {"SUN", "LCSM100",              "rdac", },
  58         {"SUN", "STK6580_6780",         "rdac", },
  59         {"SUN", "SUN_6180",             "rdac", },
  60         {"SUN", "ArrayStorage",         "rdac", },
  61         {"DELL", "MD3",                 "rdac", },
  62         {"NETAPP", "INF-01-00",         "rdac", },
  63         {"LSI", "INF-01-00",            "rdac", },
  64         {"ENGENIO", "INF-01-00",        "rdac", },
  65         {"LENOVO", "DE_Series",         "rdac", },
  66         {NULL, NULL,                    NULL },
  67 };
  68
  69 static const char *
  70 scsi_dh_find_driver(struct scsi_device *sdev)
  71 {
  72         const struct scsi_dh_blist *b;
  73
  74         if (scsi_device_tpgs(sdev))
  75                 return "alua";
  76
  77         for (b = scsi_dh_blist; b->vendor; b++) {
  78                 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
  79                     !strncmp(sdev->model, b->model, strlen(b->model))) {
  80                         return b->driver;
  81                 }
  82         }
  83         return NULL;
  84 }
  85
  86
  87 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
  88 {
  89         struct scsi_device_handler *tmp, *found = NULL;
  90
  91         spin_lock(&list_lock);
  92         list_for_each_entry(tmp, &scsi_dh_list, list) {
  93                 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
  94                         found = tmp;
  95                         break;
  96                 }
  97         }
  98         spin_unlock(&list_lock);
  99         return found;
 100 }
 101
 102 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 103 {
 104         struct scsi_device_handler *dh;
 105
 106         if (!name || strlen(name) == 0)
 107                 return NULL;
 108
 109         dh = __scsi_dh_lookup(name);
 110         if (!dh) {
 111                 request_module("scsi_dh_%s", name);
 112                 dh = __scsi_dh_lookup(name);
 113         }
 114
 115         return dh;
 116 }
 117
 118 /*
 119  * scsi_dh_handler_attach - Attach a device handler to a device
 120  * @sdev - SCSI device the device handler should attach to
 121  * @scsi_dh - The device handler to attach
 122  */
 123 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 124                                   struct scsi_device_handler *scsi_dh)
 125 {
 126         int error, ret = 0;
 127
 128         if (!try_module_get(scsi_dh->module))
 129                 return -EINVAL;
 130
 131         error = scsi_dh->attach(sdev);
 132         if (error != SCSI_DH_OK) {
 133                 switch (error) {
 134                 case SCSI_DH_NOMEM:
 135                         ret = -ENOMEM;
 136                         break;
 137                 case SCSI_DH_RES_TEMP_UNAVAIL:
 138                         ret = -EAGAIN;
 139                         break;
 140                 case SCSI_DH_DEV_UNSUPP:
 141                 case SCSI_DH_NOSYS:
 142                         ret = -ENODEV;
 143                         break;
 144                 default:
 145                         ret = -EINVAL;
 146                         break;
 147                 }
 148                 if (ret != -ENODEV)
 149                         sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 150                                     scsi_dh->name, error);
 151                 module_put(scsi_dh->module);
 152         } else
 153                 sdev->handler = scsi_dh;
 154
 155         return ret;
 156 }
 157
 158 /*
 159  * scsi_dh_handler_detach - Detach a device handler from a device
 160  * @sdev - SCSI device the device handler should be detached from
 161  */
 162 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 163 {
 164         sdev->handler->detach(sdev);
 165         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 166         module_put(sdev->handler->module);
 167 }
 168
 169 void scsi_dh_add_device(struct scsi_device *sdev)
 170 {
 171         struct scsi_device_handler *devinfo = NULL;
 172         const char *drv;
 173
 174         drv = scsi_dh_find_driver(sdev);
 175         if (drv)
 176                 devinfo = __scsi_dh_lookup(drv);
 177         /*
 178          * device_handler is optional, so ignore errors
 179          * from scsi_dh_handler_attach()
 180          */
 181         if (devinfo)
 182                 (void)scsi_dh_handler_attach(sdev, devinfo);
 183 }
 184
 185 void scsi_dh_release_device(struct scsi_device *sdev)
 186 {
 187         if (sdev->handler)
 188                 scsi_dh_handler_detach(sdev);
 189 }
 190
 191 /*
 192  * scsi_register_device_handler - register a device handler personality
 193  *      module.
 194  * @scsi_dh - device handler to be registered.
 195  *
 196  * Returns 0 on success, -EBUSY if handler already registered.
 197  */
 198 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 199 {
 200         if (__scsi_dh_lookup(scsi_dh->name))
 201                 return -EBUSY;
 202
 203         if (!scsi_dh->attach || !scsi_dh->detach)
 204                 return -EINVAL;
 205
 206         spin_lock(&list_lock);
 207         list_add(&scsi_dh->list, &scsi_dh_list);
 208         spin_unlock(&list_lock);
 209
 210         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 211
 212         return SCSI_DH_OK;
 213 }
 214 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 215
 216 /*
 217  * scsi_unregister_device_handler - register a device handler personality
 218  *      module.
 219  * @scsi_dh - device handler to be unregistered.
 220  *
 221  * Returns 0 on success, -ENODEV if handler not registered.
 222  */
 223 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 224 {
 225         if (!__scsi_dh_lookup(scsi_dh->name))
 226                 return -ENODEV;
 227
 228         spin_lock(&list_lock);
 229         list_del(&scsi_dh->list);
 230         spin_unlock(&list_lock);
 231         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 232
 233         return SCSI_DH_OK;
 234 }
 235 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 236
 237 /*
 238  * scsi_dh_activate - activate the path associated with the scsi_device
 239  *      corresponding to the given request queue.
 240  *     Returns immediately without waiting for activation to be completed.
 241  * @q    - Request queue that is associated with the scsi_device to be
 242  *         activated.
 243  * @fn   - Function to be called upon completion of the activation.
 244  *         Function fn is called with data (below) and the error code.
 245  *         Function fn may be called from the same calling context. So,
 246  *         do not hold the lock in the caller which may be needed in fn.
 247  * @data - data passed to the function fn upon completion.
 248  *
 249  */
 250 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 251 {
 252         struct scsi_device *sdev;
 253         int err = SCSI_DH_NOSYS;
 254
 255         sdev = scsi_device_from_queue(q);
 256         if (!sdev) {
 257                 if (fn)
 258                         fn(data, err);
 259                 return err;
 260         }
 261
 262         if (!sdev->handler)
 263                 goto out_fn;
 264         err = SCSI_DH_NOTCONN;
 265         if (sdev->sdev_state == SDEV_CANCEL ||
 266             sdev->sdev_state == SDEV_DEL)
 267                 goto out_fn;
 268
 269         err = SCSI_DH_DEV_OFFLINED;
 270         if (sdev->sdev_state == SDEV_OFFLINE)
 271                 goto out_fn;
 272
 273         if (sdev->handler->activate)
 274                 err = sdev->handler->activate(sdev, fn, data);
 275
 276 out_put_device:
 277         put_device(&sdev->sdev_gendev);
 278         return err;
 279
 280 out_fn:
 281         if (fn)
 282                 fn(data, err);
 283         goto out_put_device;
 284 }
 285 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 286
 287 /*
 288  * scsi_dh_set_params - set the parameters for the device as per the
 289  *      string specified in params.
 290  * @q - Request queue that is associated with the scsi_device for
 291  *      which the parameters to be set.
 292  * @params - parameters in the following format
 293  *      "no_of_params\0param1\0param2\0param3\0...\0"
 294  *      for example, string for 2 parameters with value 10 and 21
 295  *      is specified as "2\010\021\0".
 296  */
 297 int scsi_dh_set_params(struct request_queue *q, const char *params)
 298 {
 299         struct scsi_device *sdev;
 300         int err = -SCSI_DH_NOSYS;
 301
 302         sdev = scsi_device_from_queue(q);
 303         if (!sdev)
 304                 return err;
 305
 306         if (sdev->handler && sdev->handler->set_params)
 307                 err = sdev->handler->set_params(sdev, params);
 308         put_device(&sdev->sdev_gendev);
 309         return err;
 310 }
 311 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 312
 313 /*
 314  * scsi_dh_attach - Attach device handler
 315  * @q - Request queue that is associated with the scsi_device
 316  *      the handler should be attached to
 317  * @name - name of the handler to attach
 318  */
 319 int scsi_dh_attach(struct request_queue *q, const char *name)
 320 {
 321         struct scsi_device *sdev;
 322         struct scsi_device_handler *scsi_dh;
 323         int err = 0;
 324
 325         sdev = scsi_device_from_queue(q);
 326         if (!sdev)
 327                 return -ENODEV;
 328
 329         scsi_dh = scsi_dh_lookup(name);
 330         if (!scsi_dh) {
 331                 err = -EINVAL;
 332                 goto out_put_device;
 333         }
 334
 335         if (sdev->handler) {
 336                 if (sdev->handler != scsi_dh)
 337                         err = -EBUSY;
 338                 goto out_put_device;
 339         }
 340
 341         err = scsi_dh_handler_attach(sdev, scsi_dh);
 342
 343 out_put_device:
 344         put_device(&sdev->sdev_gendev);
 345         return err;
 346 }
 347 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 348
 349 /*
 350  * scsi_dh_attached_handler_name - Get attached device handler's name
 351  * @q - Request queue that is associated with the scsi_device
 352  *      that may have a device handler attached
 353  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 354  *
 355  * Returns name of attached handler, NULL if no handler is attached.
 356  * Caller must take care to free the returned string.
 357  */
 358 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 359 {
 360         struct scsi_device *sdev;
 361         const char *handler_name = NULL;
 362
 363         sdev = scsi_device_from_queue(q);
 364         if (!sdev)
 365                 return NULL;
 366
 367         if (sdev->handler)
 368                 handler_name = kstrdup(sdev->handler->name, gfp);
 369         put_device(&sdev->sdev_gendev);
 370         return handler_name;
 371 }
 372 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);