drivers/scsi/scsi_dh.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * SCSI device handler infrastructure.
   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         {"FUJITSU", "ETERNUS_AHB",      "rdac", },
  67         {NULL, NULL,                    NULL },
  68 };
  69
  70 static const char *
  71 scsi_dh_find_driver(struct scsi_device *sdev)
  72 {
  73         const struct scsi_dh_blist *b;
  74
  75         if (scsi_device_tpgs(sdev))
  76                 return "alua";
  77
  78         for (b = scsi_dh_blist; b->vendor; b++) {
  79                 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
  80                     !strncmp(sdev->model, b->model, strlen(b->model))) {
  81                         return b->driver;
  82                 }
  83         }
  84         return NULL;
  85 }
  86
  87
  88 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
  89 {
  90         struct scsi_device_handler *tmp, *found = NULL;
  91
  92         spin_lock(&list_lock);
  93         list_for_each_entry(tmp, &scsi_dh_list, list) {
  94                 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
  95                         found = tmp;
  96                         break;
  97                 }
  98         }
  99         spin_unlock(&list_lock);
 100         return found;
 101 }
 102
 103 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 104 {
 105         struct scsi_device_handler *dh;
 106
 107         if (!name || strlen(name) == 0)
 108                 return NULL;
 109
 110         dh = __scsi_dh_lookup(name);
 111         if (!dh) {
 112                 request_module("scsi_dh_%s", name);
 113                 dh = __scsi_dh_lookup(name);
 114         }
 115
 116         return dh;
 117 }
 118
 119 /*
 120  * scsi_dh_handler_attach - Attach a device handler to a device
 121  * @sdev - SCSI device the device handler should attach to
 122  * @scsi_dh - The device handler to attach
 123  */
 124 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 125                                   struct scsi_device_handler *scsi_dh)
 126 {
 127         int error, ret = 0;
 128
 129         if (!try_module_get(scsi_dh->module))
 130                 return -EINVAL;
 131
 132         error = scsi_dh->attach(sdev);
 133         if (error != SCSI_DH_OK) {
 134                 switch (error) {
 135                 case SCSI_DH_NOMEM:
 136                         ret = -ENOMEM;
 137                         break;
 138                 case SCSI_DH_RES_TEMP_UNAVAIL:
 139                         ret = -EAGAIN;
 140                         break;
 141                 case SCSI_DH_DEV_UNSUPP:
 142                 case SCSI_DH_NOSYS:
 143                         ret = -ENODEV;
 144                         break;
 145                 default:
 146                         ret = -EINVAL;
 147                         break;
 148                 }
 149                 if (ret != -ENODEV)
 150                         sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 151                                     scsi_dh->name, error);
 152                 module_put(scsi_dh->module);
 153         } else
 154                 sdev->handler = scsi_dh;
 155
 156         return ret;
 157 }
 158
 159 /*
 160  * scsi_dh_handler_detach - Detach a device handler from a device
 161  * @sdev - SCSI device the device handler should be detached from
 162  */
 163 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 164 {
 165         sdev->handler->detach(sdev);
 166         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 167         module_put(sdev->handler->module);
 168 }
 169
 170 void scsi_dh_add_device(struct scsi_device *sdev)
 171 {
 172         struct scsi_device_handler *devinfo = NULL;
 173         const char *drv;
 174
 175         drv = scsi_dh_find_driver(sdev);
 176         if (drv)
 177                 devinfo = __scsi_dh_lookup(drv);
 178         /*
 179          * device_handler is optional, so ignore errors
 180          * from scsi_dh_handler_attach()
 181          */
 182         if (devinfo)
 183                 (void)scsi_dh_handler_attach(sdev, devinfo);
 184 }
 185
 186 void scsi_dh_release_device(struct scsi_device *sdev)
 187 {
 188         if (sdev->handler)
 189                 scsi_dh_handler_detach(sdev);
 190 }
 191
 192 /*
 193  * scsi_register_device_handler - register a device handler personality
 194  *      module.
 195  * @scsi_dh - device handler to be registered.
 196  *
 197  * Returns 0 on success, -EBUSY if handler already registered.
 198  */
 199 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 200 {
 201         if (__scsi_dh_lookup(scsi_dh->name))
 202                 return -EBUSY;
 203
 204         if (!scsi_dh->attach || !scsi_dh->detach)
 205                 return -EINVAL;
 206
 207         spin_lock(&list_lock);
 208         list_add(&scsi_dh->list, &scsi_dh_list);
 209         spin_unlock(&list_lock);
 210
 211         printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
 212
 213         return SCSI_DH_OK;
 214 }
 215 EXPORT_SYMBOL_GPL(scsi_register_device_handler);
 216
 217 /*
 218  * scsi_unregister_device_handler - register a device handler personality
 219  *      module.
 220  * @scsi_dh - device handler to be unregistered.
 221  *
 222  * Returns 0 on success, -ENODEV if handler not registered.
 223  */
 224 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 225 {
 226         if (!__scsi_dh_lookup(scsi_dh->name))
 227                 return -ENODEV;
 228
 229         spin_lock(&list_lock);
 230         list_del(&scsi_dh->list);
 231         spin_unlock(&list_lock);
 232         printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
 233
 234         return SCSI_DH_OK;
 235 }
 236 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
 237
 238 /*
 239  * scsi_dh_activate - activate the path associated with the scsi_device
 240  *      corresponding to the given request queue.
 241  *     Returns immediately without waiting for activation to be completed.
 242  * @q    - Request queue that is associated with the scsi_device to be
 243  *         activated.
 244  * @fn   - Function to be called upon completion of the activation.
 245  *         Function fn is called with data (below) and the error code.
 246  *         Function fn may be called from the same calling context. So,
 247  *         do not hold the lock in the caller which may be needed in fn.
 248  * @data - data passed to the function fn upon completion.
 249  *
 250  */
 251 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 252 {
 253         struct scsi_device *sdev;
 254         int err = SCSI_DH_NOSYS;
 255
 256         sdev = scsi_device_from_queue(q);
 257         if (!sdev) {
 258                 if (fn)
 259                         fn(data, err);
 260                 return err;
 261         }
 262
 263         if (!sdev->handler)
 264                 goto out_fn;
 265         err = SCSI_DH_NOTCONN;
 266         if (sdev->sdev_state == SDEV_CANCEL ||
 267             sdev->sdev_state == SDEV_DEL)
 268                 goto out_fn;
 269
 270         err = SCSI_DH_DEV_OFFLINED;
 271         if (sdev->sdev_state == SDEV_OFFLINE)
 272                 goto out_fn;
 273
 274         if (sdev->handler->activate)
 275                 err = sdev->handler->activate(sdev, fn, data);
 276
 277 out_put_device:
 278         put_device(&sdev->sdev_gendev);
 279         return err;
 280
 281 out_fn:
 282         if (fn)
 283                 fn(data, err);
 284         goto out_put_device;
 285 }
 286 EXPORT_SYMBOL_GPL(scsi_dh_activate);
 287
 288 /*
 289  * scsi_dh_set_params - set the parameters for the device as per the
 290  *      string specified in params.
 291  * @q - Request queue that is associated with the scsi_device for
 292  *      which the parameters to be set.
 293  * @params - parameters in the following format
 294  *      "no_of_params\0param1\0param2\0param3\0...\0"
 295  *      for example, string for 2 parameters with value 10 and 21
 296  *      is specified as "2\010\021\0".
 297  */
 298 int scsi_dh_set_params(struct request_queue *q, const char *params)
 299 {
 300         struct scsi_device *sdev;
 301         int err = -SCSI_DH_NOSYS;
 302
 303         sdev = scsi_device_from_queue(q);
 304         if (!sdev)
 305                 return err;
 306
 307         if (sdev->handler && sdev->handler->set_params)
 308                 err = sdev->handler->set_params(sdev, params);
 309         put_device(&sdev->sdev_gendev);
 310         return err;
 311 }
 312 EXPORT_SYMBOL_GPL(scsi_dh_set_params);
 313
 314 /*
 315  * scsi_dh_attach - Attach device handler
 316  * @q - Request queue that is associated with the scsi_device
 317  *      the handler should be attached to
 318  * @name - name of the handler to attach
 319  */
 320 int scsi_dh_attach(struct request_queue *q, const char *name)
 321 {
 322         struct scsi_device *sdev;
 323         struct scsi_device_handler *scsi_dh;
 324         int err = 0;
 325
 326         sdev = scsi_device_from_queue(q);
 327         if (!sdev)
 328                 return -ENODEV;
 329
 330         scsi_dh = scsi_dh_lookup(name);
 331         if (!scsi_dh) {
 332                 err = -EINVAL;
 333                 goto out_put_device;
 334         }
 335
 336         if (sdev->handler) {
 337                 if (sdev->handler != scsi_dh)
 338                         err = -EBUSY;
 339                 goto out_put_device;
 340         }
 341
 342         err = scsi_dh_handler_attach(sdev, scsi_dh);
 343
 344 out_put_device:
 345         put_device(&sdev->sdev_gendev);
 346         return err;
 347 }
 348 EXPORT_SYMBOL_GPL(scsi_dh_attach);
 349
 350 /*
 351  * scsi_dh_attached_handler_name - Get attached device handler's name
 352  * @q - Request queue that is associated with the scsi_device
 353  *      that may have a device handler attached
 354  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
 355  *
 356  * Returns name of attached handler, NULL if no handler is attached.
 357  * Caller must take care to free the returned string.
 358  */
 359 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 360 {
 361         struct scsi_device *sdev;
 362         const char *handler_name = NULL;
 363
 364         sdev = scsi_device_from_queue(q);
 365         if (!sdev)
 366                 return NULL;
 367
 368         if (sdev->handler)
 369                 handler_name = kstrdup(sdev->handler->name, gfp);
 370         put_device(&sdev->sdev_gendev);
 371         return handler_name;
 372 }
 373 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);