Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 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 <scsi/scsi_dh.h> |
| 25 | #include "../scsi_priv.h" |
| 26 | |
| 27 | static DEFINE_SPINLOCK(list_lock); |
| 28 | static LIST_HEAD(scsi_dh_list); |
| 29 | |
| 30 | static struct scsi_device_handler *get_device_handler(const char *name) |
| 31 | { |
| 32 | struct scsi_device_handler *tmp, *found = NULL; |
| 33 | |
| 34 | spin_lock(&list_lock); |
| 35 | list_for_each_entry(tmp, &scsi_dh_list, list) { |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 36 | if (!strncmp(tmp->name, name, strlen(tmp->name))) { |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 37 | found = tmp; |
| 38 | break; |
| 39 | } |
| 40 | } |
| 41 | spin_unlock(&list_lock); |
| 42 | return found; |
| 43 | } |
| 44 | |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 45 | static int device_handler_match(struct scsi_device_handler *tmp, |
| 46 | struct scsi_device *sdev) |
| 47 | { |
| 48 | int i; |
| 49 | |
| 50 | for(i = 0; tmp->devlist[i].vendor; i++) { |
| 51 | if (!strncmp(sdev->vendor, tmp->devlist[i].vendor, |
| 52 | strlen(tmp->devlist[i].vendor)) && |
| 53 | !strncmp(sdev->model, tmp->devlist[i].model, |
| 54 | strlen(tmp->devlist[i].model))) { |
| 55 | return 1; |
| 56 | } |
| 57 | } |
| 58 | |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | /* |
| 63 | * scsi_dh_handler_attach - Attach a device handler to a device |
| 64 | * @sdev - SCSI device the device handler should attach to |
| 65 | * @scsi_dh - The device handler to attach |
| 66 | */ |
| 67 | static int scsi_dh_handler_attach(struct scsi_device *sdev, |
| 68 | struct scsi_device_handler *scsi_dh) |
| 69 | { |
| 70 | int err = 0; |
| 71 | |
| 72 | if (sdev->scsi_dh_data) { |
| 73 | if (sdev->scsi_dh_data->scsi_dh != scsi_dh) |
| 74 | err = -EBUSY; |
| 75 | } else if (scsi_dh->attach) |
| 76 | err = scsi_dh->attach(sdev); |
| 77 | |
| 78 | return err; |
| 79 | } |
| 80 | |
| 81 | /* |
| 82 | * scsi_dh_handler_detach - Detach a device handler from a device |
| 83 | * @sdev - SCSI device the device handler should be detached from |
| 84 | * @scsi_dh - Device handler to be detached |
| 85 | * |
| 86 | * Detach from a device handler. If a device handler is specified, |
Hannes Reinecke | 4c05ae5 | 2008-07-17 16:52:57 -0700 | [diff] [blame^] | 87 | * only detach if the currently attached handler matches @scsi_dh. |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 88 | */ |
| 89 | static void scsi_dh_handler_detach(struct scsi_device *sdev, |
| 90 | struct scsi_device_handler *scsi_dh) |
| 91 | { |
| 92 | if (!sdev->scsi_dh_data) |
| 93 | return; |
| 94 | |
| 95 | if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh) |
| 96 | return; |
| 97 | |
| 98 | if (!scsi_dh) |
| 99 | scsi_dh = sdev->scsi_dh_data->scsi_dh; |
| 100 | |
| 101 | if (scsi_dh && scsi_dh->detach) |
| 102 | scsi_dh->detach(sdev); |
| 103 | } |
| 104 | |
| 105 | /* |
Hannes Reinecke | 4c05ae5 | 2008-07-17 16:52:57 -0700 | [diff] [blame^] | 106 | * Functions for sysfs attribute 'dh_state' |
| 107 | */ |
| 108 | static ssize_t |
| 109 | store_dh_state(struct device *dev, struct device_attribute *attr, |
| 110 | const char *buf, size_t count) |
| 111 | { |
| 112 | struct scsi_device *sdev = to_scsi_device(dev); |
| 113 | struct scsi_device_handler *scsi_dh; |
| 114 | int err = -EINVAL; |
| 115 | |
| 116 | if (!sdev->scsi_dh_data) { |
| 117 | /* |
| 118 | * Attach to a device handler |
| 119 | */ |
| 120 | if (!(scsi_dh = get_device_handler(buf))) |
| 121 | return err; |
| 122 | err = scsi_dh_handler_attach(sdev, scsi_dh); |
| 123 | } else { |
| 124 | scsi_dh = sdev->scsi_dh_data->scsi_dh; |
| 125 | if (!strncmp(buf, "detach", 6)) { |
| 126 | /* |
| 127 | * Detach from a device handler |
| 128 | */ |
| 129 | scsi_dh_handler_detach(sdev, scsi_dh); |
| 130 | err = 0; |
| 131 | } else if (!strncmp(buf, "activate", 8)) { |
| 132 | /* |
| 133 | * Activate a device handler |
| 134 | */ |
| 135 | if (scsi_dh->activate) |
| 136 | err = scsi_dh->activate(sdev); |
| 137 | else |
| 138 | err = 0; |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | return err<0?err:count; |
| 143 | } |
| 144 | |
| 145 | static ssize_t |
| 146 | show_dh_state(struct device *dev, struct device_attribute *attr, char *buf) |
| 147 | { |
| 148 | struct scsi_device *sdev = to_scsi_device(dev); |
| 149 | |
| 150 | if (!sdev->scsi_dh_data) |
| 151 | return snprintf(buf, 20, "detached\n"); |
| 152 | |
| 153 | return snprintf(buf, 20, "%s\n", sdev->scsi_dh_data->scsi_dh->name); |
| 154 | } |
| 155 | |
| 156 | static struct device_attribute scsi_dh_state_attr = |
| 157 | __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state, |
| 158 | store_dh_state); |
| 159 | |
| 160 | /* |
| 161 | * scsi_dh_sysfs_attr_add - Callback for scsi_init_dh |
| 162 | */ |
| 163 | static int scsi_dh_sysfs_attr_add(struct device *dev, void *data) |
| 164 | { |
| 165 | struct scsi_device *sdev; |
| 166 | int err; |
| 167 | |
| 168 | if (!scsi_is_sdev_device(dev)) |
| 169 | return 0; |
| 170 | |
| 171 | sdev = to_scsi_device(dev); |
| 172 | |
| 173 | err = device_create_file(&sdev->sdev_gendev, |
| 174 | &scsi_dh_state_attr); |
| 175 | |
| 176 | return 0; |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * scsi_dh_sysfs_attr_remove - Callback for scsi_exit_dh |
| 181 | */ |
| 182 | static int scsi_dh_sysfs_attr_remove(struct device *dev, void *data) |
| 183 | { |
| 184 | struct scsi_device *sdev; |
| 185 | |
| 186 | if (!scsi_is_sdev_device(dev)) |
| 187 | return 0; |
| 188 | |
| 189 | sdev = to_scsi_device(dev); |
| 190 | |
| 191 | device_remove_file(&sdev->sdev_gendev, |
| 192 | &scsi_dh_state_attr); |
| 193 | |
| 194 | return 0; |
| 195 | } |
| 196 | |
| 197 | /* |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 198 | * scsi_dh_notifier - notifier chain callback |
| 199 | */ |
| 200 | static int scsi_dh_notifier(struct notifier_block *nb, |
| 201 | unsigned long action, void *data) |
| 202 | { |
| 203 | struct device *dev = data; |
| 204 | struct scsi_device *sdev; |
| 205 | int err = 0; |
| 206 | struct scsi_device_handler *tmp, *devinfo = NULL; |
| 207 | |
| 208 | if (!scsi_is_sdev_device(dev)) |
| 209 | return 0; |
| 210 | |
| 211 | sdev = to_scsi_device(dev); |
| 212 | |
| 213 | spin_lock(&list_lock); |
| 214 | list_for_each_entry(tmp, &scsi_dh_list, list) { |
| 215 | if (device_handler_match(tmp, sdev)) { |
| 216 | devinfo = tmp; |
| 217 | break; |
| 218 | } |
| 219 | } |
| 220 | spin_unlock(&list_lock); |
| 221 | |
| 222 | if (!devinfo) |
| 223 | goto out; |
| 224 | |
| 225 | if (action == BUS_NOTIFY_ADD_DEVICE) { |
| 226 | err = scsi_dh_handler_attach(sdev, devinfo); |
Hannes Reinecke | 4c05ae5 | 2008-07-17 16:52:57 -0700 | [diff] [blame^] | 227 | if (!err) |
| 228 | err = device_create_file(dev, &scsi_dh_state_attr); |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 229 | } else if (action == BUS_NOTIFY_DEL_DEVICE) { |
Hannes Reinecke | 4c05ae5 | 2008-07-17 16:52:57 -0700 | [diff] [blame^] | 230 | device_remove_file(dev, &scsi_dh_state_attr); |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 231 | scsi_dh_handler_detach(sdev, NULL); |
| 232 | } |
| 233 | out: |
| 234 | return err; |
| 235 | } |
| 236 | |
| 237 | /* |
| 238 | * scsi_dh_notifier_add - Callback for scsi_register_device_handler |
| 239 | */ |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 240 | static int scsi_dh_notifier_add(struct device *dev, void *data) |
| 241 | { |
| 242 | struct scsi_device_handler *scsi_dh = data; |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 243 | struct scsi_device *sdev; |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 244 | |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 245 | if (!scsi_is_sdev_device(dev)) |
| 246 | return 0; |
| 247 | |
| 248 | if (!get_device(dev)) |
| 249 | return 0; |
| 250 | |
| 251 | sdev = to_scsi_device(dev); |
| 252 | |
| 253 | if (device_handler_match(scsi_dh, sdev)) |
| 254 | scsi_dh_handler_attach(sdev, scsi_dh); |
| 255 | |
| 256 | put_device(dev); |
| 257 | |
| 258 | return 0; |
| 259 | } |
| 260 | |
| 261 | /* |
| 262 | * scsi_dh_notifier_remove - Callback for scsi_unregister_device_handler |
| 263 | */ |
| 264 | static int scsi_dh_notifier_remove(struct device *dev, void *data) |
| 265 | { |
| 266 | struct scsi_device_handler *scsi_dh = data; |
| 267 | struct scsi_device *sdev; |
| 268 | |
| 269 | if (!scsi_is_sdev_device(dev)) |
| 270 | return 0; |
| 271 | |
| 272 | if (!get_device(dev)) |
| 273 | return 0; |
| 274 | |
| 275 | sdev = to_scsi_device(dev); |
| 276 | |
| 277 | scsi_dh_handler_detach(sdev, scsi_dh); |
| 278 | |
| 279 | put_device(dev); |
| 280 | |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 281 | return 0; |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * scsi_register_device_handler - register a device handler personality |
| 286 | * module. |
| 287 | * @scsi_dh - device handler to be registered. |
| 288 | * |
| 289 | * Returns 0 on success, -EBUSY if handler already registered. |
| 290 | */ |
| 291 | int scsi_register_device_handler(struct scsi_device_handler *scsi_dh) |
| 292 | { |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 293 | if (get_device_handler(scsi_dh->name)) |
| 294 | return -EBUSY; |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 295 | |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 296 | spin_lock(&list_lock); |
| 297 | list_add(&scsi_dh->list, &scsi_dh_list); |
| 298 | spin_unlock(&list_lock); |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 299 | bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, scsi_dh_notifier_add); |
| 300 | printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name); |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 301 | |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 302 | return SCSI_DH_OK; |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 303 | } |
| 304 | EXPORT_SYMBOL_GPL(scsi_register_device_handler); |
| 305 | |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 306 | /* |
| 307 | * scsi_unregister_device_handler - register a device handler personality |
| 308 | * module. |
| 309 | * @scsi_dh - device handler to be unregistered. |
| 310 | * |
| 311 | * Returns 0 on success, -ENODEV if handler not registered. |
| 312 | */ |
| 313 | int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh) |
| 314 | { |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 315 | if (!get_device_handler(scsi_dh->name)) |
| 316 | return -ENODEV; |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 317 | |
| 318 | bus_for_each_dev(&scsi_bus_type, NULL, scsi_dh, |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 319 | scsi_dh_notifier_remove); |
| 320 | |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 321 | spin_lock(&list_lock); |
| 322 | list_del(&scsi_dh->list); |
| 323 | spin_unlock(&list_lock); |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 324 | printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name); |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 325 | |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 326 | return SCSI_DH_OK; |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 327 | } |
| 328 | EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); |
| 329 | |
| 330 | /* |
| 331 | * scsi_dh_activate - activate the path associated with the scsi_device |
| 332 | * corresponding to the given request queue. |
| 333 | * @q - Request queue that is associated with the scsi_device to be |
| 334 | * activated. |
| 335 | */ |
| 336 | int scsi_dh_activate(struct request_queue *q) |
| 337 | { |
| 338 | int err = 0; |
| 339 | unsigned long flags; |
| 340 | struct scsi_device *sdev; |
| 341 | struct scsi_device_handler *scsi_dh = NULL; |
| 342 | |
| 343 | spin_lock_irqsave(q->queue_lock, flags); |
| 344 | sdev = q->queuedata; |
| 345 | if (sdev && sdev->scsi_dh_data) |
| 346 | scsi_dh = sdev->scsi_dh_data->scsi_dh; |
| 347 | if (!scsi_dh || !get_device(&sdev->sdev_gendev)) |
| 348 | err = SCSI_DH_NOSYS; |
| 349 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 350 | |
| 351 | if (err) |
| 352 | return err; |
| 353 | |
| 354 | if (scsi_dh->activate) |
| 355 | err = scsi_dh->activate(sdev); |
| 356 | put_device(&sdev->sdev_gendev); |
| 357 | return err; |
| 358 | } |
| 359 | EXPORT_SYMBOL_GPL(scsi_dh_activate); |
| 360 | |
| 361 | /* |
| 362 | * scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for |
| 363 | * the given name. FALSE(0) otherwise. |
| 364 | * @name - name of the device handler. |
| 365 | */ |
| 366 | int scsi_dh_handler_exist(const char *name) |
| 367 | { |
| 368 | return (get_device_handler(name) != NULL); |
| 369 | } |
| 370 | EXPORT_SYMBOL_GPL(scsi_dh_handler_exist); |
| 371 | |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 372 | static struct notifier_block scsi_dh_nb = { |
| 373 | .notifier_call = scsi_dh_notifier |
| 374 | }; |
| 375 | |
| 376 | static int __init scsi_dh_init(void) |
| 377 | { |
| 378 | int r; |
| 379 | |
| 380 | r = bus_register_notifier(&scsi_bus_type, &scsi_dh_nb); |
| 381 | |
Hannes Reinecke | 4c05ae5 | 2008-07-17 16:52:57 -0700 | [diff] [blame^] | 382 | if (!r) |
| 383 | bus_for_each_dev(&scsi_bus_type, NULL, NULL, |
| 384 | scsi_dh_sysfs_attr_add); |
| 385 | |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 386 | return r; |
| 387 | } |
| 388 | |
| 389 | static void __exit scsi_dh_exit(void) |
| 390 | { |
Hannes Reinecke | 4c05ae5 | 2008-07-17 16:52:57 -0700 | [diff] [blame^] | 391 | bus_for_each_dev(&scsi_bus_type, NULL, NULL, |
| 392 | scsi_dh_sysfs_attr_remove); |
Hannes Reinecke | 765cbc6 | 2008-07-17 16:52:51 -0700 | [diff] [blame] | 393 | bus_unregister_notifier(&scsi_bus_type, &scsi_dh_nb); |
| 394 | } |
| 395 | |
| 396 | module_init(scsi_dh_init); |
| 397 | module_exit(scsi_dh_exit); |
| 398 | |
Chandra Seetharaman | a6a8d9f | 2008-05-01 14:49:46 -0700 | [diff] [blame] | 399 | MODULE_DESCRIPTION("SCSI device handler"); |
| 400 | MODULE_AUTHOR("Chandra Seetharaman <sekharan@us.ibm.com>"); |
| 401 | MODULE_LICENSE("GPL"); |