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