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(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_remove_device(struct scsi_device *sdev) 236 { 237 if (sdev->handler) 238 scsi_dh_handler_detach(sdev); 239 device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr); 240 } 241 242 /* 243 * scsi_register_device_handler - register a device handler personality 244 * module. 245 * @scsi_dh - device handler to be registered. 246 * 247 * Returns 0 on success, -EBUSY if handler already registered. 248 */ 249 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh) 250 { 251 if (__scsi_dh_lookup(scsi_dh->name)) 252 return -EBUSY; 253 254 if (!scsi_dh->attach || !scsi_dh->detach) 255 return -EINVAL; 256 257 spin_lock(&list_lock); 258 list_add(&scsi_dh->list, &scsi_dh_list); 259 spin_unlock(&list_lock); 260 261 printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name); 262 263 return SCSI_DH_OK; 264 } 265 EXPORT_SYMBOL_GPL(scsi_register_device_handler); 266 267 /* 268 * scsi_unregister_device_handler - register a device handler personality 269 * module. 270 * @scsi_dh - device handler to be unregistered. 271 * 272 * Returns 0 on success, -ENODEV if handler not registered. 273 */ 274 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh) 275 { 276 if (!__scsi_dh_lookup(scsi_dh->name)) 277 return -ENODEV; 278 279 spin_lock(&list_lock); 280 list_del(&scsi_dh->list); 281 spin_unlock(&list_lock); 282 printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name); 283 284 return SCSI_DH_OK; 285 } 286 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); 287 288 static struct scsi_device *get_sdev_from_queue(struct request_queue *q) 289 { 290 struct scsi_device *sdev; 291 unsigned long flags; 292 293 spin_lock_irqsave(q->queue_lock, flags); 294 sdev = q->queuedata; 295 if (!sdev || !get_device(&sdev->sdev_gendev)) 296 sdev = NULL; 297 spin_unlock_irqrestore(q->queue_lock, flags); 298 299 return sdev; 300 } 301 302 /* 303 * scsi_dh_activate - activate the path associated with the scsi_device 304 * corresponding to the given request queue. 305 * Returns immediately without waiting for activation to be completed. 306 * @q - Request queue that is associated with the scsi_device to be 307 * activated. 308 * @fn - Function to be called upon completion of the activation. 309 * Function fn is called with data (below) and the error code. 310 * Function fn may be called from the same calling context. So, 311 * do not hold the lock in the caller which may be needed in fn. 312 * @data - data passed to the function fn upon completion. 313 * 314 */ 315 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data) 316 { 317 struct scsi_device *sdev; 318 int err = SCSI_DH_NOSYS; 319 320 sdev = get_sdev_from_queue(q); 321 if (!sdev) { 322 if (fn) 323 fn(data, err); 324 return err; 325 } 326 327 if (!sdev->handler) 328 goto out_fn; 329 err = SCSI_DH_NOTCONN; 330 if (sdev->sdev_state == SDEV_CANCEL || 331 sdev->sdev_state == SDEV_DEL) 332 goto out_fn; 333 334 err = SCSI_DH_DEV_OFFLINED; 335 if (sdev->sdev_state == SDEV_OFFLINE) 336 goto out_fn; 337 338 if (sdev->handler->activate) 339 err = sdev->handler->activate(sdev, fn, data); 340 341 out_put_device: 342 put_device(&sdev->sdev_gendev); 343 return err; 344 345 out_fn: 346 if (fn) 347 fn(data, err); 348 goto out_put_device; 349 } 350 EXPORT_SYMBOL_GPL(scsi_dh_activate); 351 352 /* 353 * scsi_dh_set_params - set the parameters for the device as per the 354 * string specified in params. 355 * @q - Request queue that is associated with the scsi_device for 356 * which the parameters to be set. 357 * @params - parameters in the following format 358 * "no_of_params\0param1\0param2\0param3\0...\0" 359 * for example, string for 2 parameters with value 10 and 21 360 * is specified as "2\010\021\0". 361 */ 362 int scsi_dh_set_params(struct request_queue *q, const char *params) 363 { 364 struct scsi_device *sdev; 365 int err = -SCSI_DH_NOSYS; 366 367 sdev = get_sdev_from_queue(q); 368 if (!sdev) 369 return err; 370 371 if (sdev->handler && sdev->handler->set_params) 372 err = sdev->handler->set_params(sdev, params); 373 put_device(&sdev->sdev_gendev); 374 return err; 375 } 376 EXPORT_SYMBOL_GPL(scsi_dh_set_params); 377 378 /* 379 * scsi_dh_attach - Attach device handler 380 * @q - Request queue that is associated with the scsi_device 381 * the handler should be attached to 382 * @name - name of the handler to attach 383 */ 384 int scsi_dh_attach(struct request_queue *q, const char *name) 385 { 386 struct scsi_device *sdev; 387 struct scsi_device_handler *scsi_dh; 388 int err = 0; 389 390 sdev = get_sdev_from_queue(q); 391 if (!sdev) 392 return -ENODEV; 393 394 scsi_dh = scsi_dh_lookup(name); 395 if (!scsi_dh) { 396 err = -EINVAL; 397 goto out_put_device; 398 } 399 400 if (sdev->handler) { 401 if (sdev->handler != scsi_dh) 402 err = -EBUSY; 403 goto out_put_device; 404 } 405 406 err = scsi_dh_handler_attach(sdev, scsi_dh); 407 408 out_put_device: 409 put_device(&sdev->sdev_gendev); 410 return err; 411 } 412 EXPORT_SYMBOL_GPL(scsi_dh_attach); 413 414 /* 415 * scsi_dh_attached_handler_name - Get attached device handler's name 416 * @q - Request queue that is associated with the scsi_device 417 * that may have a device handler attached 418 * @gfp - the GFP mask used in the kmalloc() call when allocating memory 419 * 420 * Returns name of attached handler, NULL if no handler is attached. 421 * Caller must take care to free the returned string. 422 */ 423 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp) 424 { 425 struct scsi_device *sdev; 426 const char *handler_name = NULL; 427 428 sdev = get_sdev_from_queue(q); 429 if (!sdev) 430 return NULL; 431 432 if (sdev->handler) 433 handler_name = kstrdup(sdev->handler->name, gfp); 434 put_device(&sdev->sdev_gendev); 435 return handler_name; 436 } 437 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name); 438