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