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 {"IBM", "3542", "rdac", }, 60 {"IBM", "3552", "rdac", }, 61 {"SGI", "TP9", "rdac", }, 62 {"SGI", "IS", "rdac", }, 63 {"STK", "OPENstorage", "rdac", }, 64 {"STK", "FLEXLINE 380", "rdac", }, 65 {"STK", "BladeCtlr", "rdac", }, 66 {"SUN", "CSM", "rdac", }, 67 {"SUN", "LCSM100", "rdac", }, 68 {"SUN", "STK6580_6780", "rdac", }, 69 {"SUN", "SUN_6180", "rdac", }, 70 {"SUN", "ArrayStorage", "rdac", }, 71 {"DELL", "MD3", "rdac", }, 72 {"NETAPP", "INF-01-00", "rdac", }, 73 {"LSI", "INF-01-00", "rdac", }, 74 {"ENGENIO", "INF-01-00", "rdac", }, 75 {NULL, NULL, NULL }, 76 }; 77 78 static const char * 79 scsi_dh_find_driver(struct scsi_device *sdev) 80 { 81 const struct scsi_dh_blist *b; 82 83 if (scsi_device_tpgs(sdev)) 84 return "alua"; 85 86 for (b = scsi_dh_blist; b->vendor; b++) { 87 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) && 88 !strncmp(sdev->model, b->model, strlen(b->model))) { 89 return b->driver; 90 } 91 } 92 return NULL; 93 } 94 95 96 static struct scsi_device_handler *__scsi_dh_lookup(const char *name) 97 { 98 struct scsi_device_handler *tmp, *found = NULL; 99 100 spin_lock(&list_lock); 101 list_for_each_entry(tmp, &scsi_dh_list, list) { 102 if (!strncmp(tmp->name, name, strlen(tmp->name))) { 103 found = tmp; 104 break; 105 } 106 } 107 spin_unlock(&list_lock); 108 return found; 109 } 110 111 static struct scsi_device_handler *scsi_dh_lookup(const char *name) 112 { 113 struct scsi_device_handler *dh; 114 115 if (!name || strlen(name) == 0) 116 return NULL; 117 118 dh = __scsi_dh_lookup(name); 119 if (!dh) { 120 request_module("scsi_dh_%s", name); 121 dh = __scsi_dh_lookup(name); 122 } 123 124 return dh; 125 } 126 127 /* 128 * scsi_dh_handler_attach - Attach a device handler to a device 129 * @sdev - SCSI device the device handler should attach to 130 * @scsi_dh - The device handler to attach 131 */ 132 static int scsi_dh_handler_attach(struct scsi_device *sdev, 133 struct scsi_device_handler *scsi_dh) 134 { 135 int error, ret = 0; 136 137 if (!try_module_get(scsi_dh->module)) 138 return -EINVAL; 139 140 error = scsi_dh->attach(sdev); 141 if (error != SCSI_DH_OK) { 142 switch (error) { 143 case SCSI_DH_NOMEM: 144 ret = -ENOMEM; 145 break; 146 case SCSI_DH_RES_TEMP_UNAVAIL: 147 ret = -EAGAIN; 148 break; 149 case SCSI_DH_DEV_UNSUPP: 150 case SCSI_DH_NOSYS: 151 ret = -ENODEV; 152 break; 153 default: 154 ret = -EINVAL; 155 break; 156 } 157 if (ret != -ENODEV) 158 sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n", 159 scsi_dh->name, error); 160 module_put(scsi_dh->module); 161 } else 162 sdev->handler = scsi_dh; 163 164 return ret; 165 } 166 167 /* 168 * scsi_dh_handler_detach - Detach a device handler from a device 169 * @sdev - SCSI device the device handler should be detached from 170 */ 171 static void scsi_dh_handler_detach(struct scsi_device *sdev) 172 { 173 sdev->handler->detach(sdev); 174 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name); 175 module_put(sdev->handler->module); 176 } 177 178 void scsi_dh_add_device(struct scsi_device *sdev) 179 { 180 struct scsi_device_handler *devinfo = NULL; 181 const char *drv; 182 183 drv = scsi_dh_find_driver(sdev); 184 if (drv) 185 devinfo = __scsi_dh_lookup(drv); 186 /* 187 * device_handler is optional, so ignore errors 188 * from scsi_dh_handler_attach() 189 */ 190 if (devinfo) 191 (void)scsi_dh_handler_attach(sdev, devinfo); 192 } 193 194 void scsi_dh_release_device(struct scsi_device *sdev) 195 { 196 if (sdev->handler) 197 scsi_dh_handler_detach(sdev); 198 } 199 200 /* 201 * scsi_register_device_handler - register a device handler personality 202 * module. 203 * @scsi_dh - device handler to be registered. 204 * 205 * Returns 0 on success, -EBUSY if handler already registered. 206 */ 207 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh) 208 { 209 if (__scsi_dh_lookup(scsi_dh->name)) 210 return -EBUSY; 211 212 if (!scsi_dh->attach || !scsi_dh->detach) 213 return -EINVAL; 214 215 spin_lock(&list_lock); 216 list_add(&scsi_dh->list, &scsi_dh_list); 217 spin_unlock(&list_lock); 218 219 printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name); 220 221 return SCSI_DH_OK; 222 } 223 EXPORT_SYMBOL_GPL(scsi_register_device_handler); 224 225 /* 226 * scsi_unregister_device_handler - register a device handler personality 227 * module. 228 * @scsi_dh - device handler to be unregistered. 229 * 230 * Returns 0 on success, -ENODEV if handler not registered. 231 */ 232 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh) 233 { 234 if (!__scsi_dh_lookup(scsi_dh->name)) 235 return -ENODEV; 236 237 spin_lock(&list_lock); 238 list_del(&scsi_dh->list); 239 spin_unlock(&list_lock); 240 printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name); 241 242 return SCSI_DH_OK; 243 } 244 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); 245 246 /* 247 * scsi_dh_activate - activate the path associated with the scsi_device 248 * corresponding to the given request queue. 249 * Returns immediately without waiting for activation to be completed. 250 * @q - Request queue that is associated with the scsi_device to be 251 * activated. 252 * @fn - Function to be called upon completion of the activation. 253 * Function fn is called with data (below) and the error code. 254 * Function fn may be called from the same calling context. So, 255 * do not hold the lock in the caller which may be needed in fn. 256 * @data - data passed to the function fn upon completion. 257 * 258 */ 259 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data) 260 { 261 struct scsi_device *sdev; 262 int err = SCSI_DH_NOSYS; 263 264 sdev = scsi_device_from_queue(q); 265 if (!sdev) { 266 if (fn) 267 fn(data, err); 268 return err; 269 } 270 271 if (!sdev->handler) 272 goto out_fn; 273 err = SCSI_DH_NOTCONN; 274 if (sdev->sdev_state == SDEV_CANCEL || 275 sdev->sdev_state == SDEV_DEL) 276 goto out_fn; 277 278 err = SCSI_DH_DEV_OFFLINED; 279 if (sdev->sdev_state == SDEV_OFFLINE) 280 goto out_fn; 281 282 if (sdev->handler->activate) 283 err = sdev->handler->activate(sdev, fn, data); 284 285 out_put_device: 286 put_device(&sdev->sdev_gendev); 287 return err; 288 289 out_fn: 290 if (fn) 291 fn(data, err); 292 goto out_put_device; 293 } 294 EXPORT_SYMBOL_GPL(scsi_dh_activate); 295 296 /* 297 * scsi_dh_set_params - set the parameters for the device as per the 298 * string specified in params. 299 * @q - Request queue that is associated with the scsi_device for 300 * which the parameters to be set. 301 * @params - parameters in the following format 302 * "no_of_params\0param1\0param2\0param3\0...\0" 303 * for example, string for 2 parameters with value 10 and 21 304 * is specified as "2\010\021\0". 305 */ 306 int scsi_dh_set_params(struct request_queue *q, const char *params) 307 { 308 struct scsi_device *sdev; 309 int err = -SCSI_DH_NOSYS; 310 311 sdev = scsi_device_from_queue(q); 312 if (!sdev) 313 return err; 314 315 if (sdev->handler && sdev->handler->set_params) 316 err = sdev->handler->set_params(sdev, params); 317 put_device(&sdev->sdev_gendev); 318 return err; 319 } 320 EXPORT_SYMBOL_GPL(scsi_dh_set_params); 321 322 /* 323 * scsi_dh_attach - Attach device handler 324 * @q - Request queue that is associated with the scsi_device 325 * the handler should be attached to 326 * @name - name of the handler to attach 327 */ 328 int scsi_dh_attach(struct request_queue *q, const char *name) 329 { 330 struct scsi_device *sdev; 331 struct scsi_device_handler *scsi_dh; 332 int err = 0; 333 334 sdev = scsi_device_from_queue(q); 335 if (!sdev) 336 return -ENODEV; 337 338 scsi_dh = scsi_dh_lookup(name); 339 if (!scsi_dh) { 340 err = -EINVAL; 341 goto out_put_device; 342 } 343 344 if (sdev->handler) { 345 if (sdev->handler != scsi_dh) 346 err = -EBUSY; 347 goto out_put_device; 348 } 349 350 err = scsi_dh_handler_attach(sdev, scsi_dh); 351 352 out_put_device: 353 put_device(&sdev->sdev_gendev); 354 return err; 355 } 356 EXPORT_SYMBOL_GPL(scsi_dh_attach); 357 358 /* 359 * scsi_dh_attached_handler_name - Get attached device handler's name 360 * @q - Request queue that is associated with the scsi_device 361 * that may have a device handler attached 362 * @gfp - the GFP mask used in the kmalloc() call when allocating memory 363 * 364 * Returns name of attached handler, NULL if no handler is attached. 365 * Caller must take care to free the returned string. 366 */ 367 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp) 368 { 369 struct scsi_device *sdev; 370 const char *handler_name = NULL; 371 372 sdev = scsi_device_from_queue(q); 373 if (!sdev) 374 return NULL; 375 376 if (sdev->handler) 377 handler_name = kstrdup(sdev->handler->name, gfp); 378 put_device(&sdev->sdev_gendev); 379 return handler_name; 380 } 381 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name); 382