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