| 1 | /* |
| 2 | * (C) 2003 David Woodhouse <dwmw2@infradead.org> |
| 3 | * |
| 4 | * Interface to Linux 2.5 block layer for MTD 'translation layers'. |
| 5 | * |
| 6 | */ |
| 7 | |
| 8 | #include <linux/kernel.h> |
| 9 | #include <linux/slab.h> |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/list.h> |
| 12 | #include <linux/fs.h> |
| 13 | #include <linux/mtd/blktrans.h> |
| 14 | #include <linux/mtd/mtd.h> |
| 15 | #include <linux/blkdev.h> |
| 16 | #include <linux/blkpg.h> |
| 17 | #include <linux/freezer.h> |
| 18 | #include <linux/spinlock.h> |
| 19 | #include <linux/hdreg.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/mutex.h> |
| 22 | #include <linux/kthread.h> |
| 23 | #include <asm/uaccess.h> |
| 24 | |
| 25 | #include "mtdcore.h" |
| 26 | |
| 27 | static LIST_HEAD(blktrans_majors); |
| 28 | |
| 29 | struct mtd_blkcore_priv { |
| 30 | struct task_struct *thread; |
| 31 | struct request_queue *rq; |
| 32 | spinlock_t queue_lock; |
| 33 | }; |
| 34 | |
| 35 | static int do_blktrans_request(struct mtd_blktrans_ops *tr, |
| 36 | struct mtd_blktrans_dev *dev, |
| 37 | struct request *req) |
| 38 | { |
| 39 | unsigned long block, nsect; |
| 40 | char *buf; |
| 41 | |
| 42 | block = blk_rq_pos(req) << 9 >> tr->blkshift; |
| 43 | nsect = blk_rq_cur_bytes(req) >> tr->blkshift; |
| 44 | |
| 45 | buf = req->buffer; |
| 46 | |
| 47 | if (!blk_fs_request(req)) |
| 48 | return -EIO; |
| 49 | |
| 50 | if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > |
| 51 | get_capacity(req->rq_disk)) |
| 52 | return -EIO; |
| 53 | |
| 54 | if (blk_discard_rq(req)) |
| 55 | return tr->discard(dev, block, nsect); |
| 56 | |
| 57 | switch(rq_data_dir(req)) { |
| 58 | case READ: |
| 59 | for (; nsect > 0; nsect--, block++, buf += tr->blksize) |
| 60 | if (tr->readsect(dev, block, buf)) |
| 61 | return -EIO; |
| 62 | return 0; |
| 63 | |
| 64 | case WRITE: |
| 65 | if (!tr->writesect) |
| 66 | return -EIO; |
| 67 | |
| 68 | for (; nsect > 0; nsect--, block++, buf += tr->blksize) |
| 69 | if (tr->writesect(dev, block, buf)) |
| 70 | return -EIO; |
| 71 | return 0; |
| 72 | |
| 73 | default: |
| 74 | printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req)); |
| 75 | return -EIO; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | static int mtd_blktrans_thread(void *arg) |
| 80 | { |
| 81 | struct mtd_blktrans_ops *tr = arg; |
| 82 | struct request_queue *rq = tr->blkcore_priv->rq; |
| 83 | struct request *req = NULL; |
| 84 | |
| 85 | /* we might get involved when memory gets low, so use PF_MEMALLOC */ |
| 86 | current->flags |= PF_MEMALLOC; |
| 87 | |
| 88 | spin_lock_irq(rq->queue_lock); |
| 89 | |
| 90 | while (!kthread_should_stop()) { |
| 91 | struct mtd_blktrans_dev *dev; |
| 92 | int res; |
| 93 | |
| 94 | if (!req && !(req = blk_fetch_request(rq))) { |
| 95 | set_current_state(TASK_INTERRUPTIBLE); |
| 96 | spin_unlock_irq(rq->queue_lock); |
| 97 | schedule(); |
| 98 | spin_lock_irq(rq->queue_lock); |
| 99 | continue; |
| 100 | } |
| 101 | |
| 102 | dev = req->rq_disk->private_data; |
| 103 | tr = dev->tr; |
| 104 | |
| 105 | spin_unlock_irq(rq->queue_lock); |
| 106 | |
| 107 | mutex_lock(&dev->lock); |
| 108 | res = do_blktrans_request(tr, dev, req); |
| 109 | mutex_unlock(&dev->lock); |
| 110 | |
| 111 | spin_lock_irq(rq->queue_lock); |
| 112 | |
| 113 | if (!__blk_end_request_cur(req, res)) |
| 114 | req = NULL; |
| 115 | } |
| 116 | |
| 117 | if (req) |
| 118 | __blk_end_request_all(req, -EIO); |
| 119 | |
| 120 | spin_unlock_irq(rq->queue_lock); |
| 121 | |
| 122 | return 0; |
| 123 | } |
| 124 | |
| 125 | static void mtd_blktrans_request(struct request_queue *rq) |
| 126 | { |
| 127 | struct mtd_blktrans_ops *tr = rq->queuedata; |
| 128 | wake_up_process(tr->blkcore_priv->thread); |
| 129 | } |
| 130 | |
| 131 | |
| 132 | static int blktrans_open(struct block_device *bdev, fmode_t mode) |
| 133 | { |
| 134 | struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data; |
| 135 | struct mtd_blktrans_ops *tr = dev->tr; |
| 136 | int ret = -ENODEV; |
| 137 | |
| 138 | if (!get_mtd_device(NULL, dev->mtd->index)) |
| 139 | goto out; |
| 140 | |
| 141 | if (!try_module_get(tr->owner)) |
| 142 | goto out_tr; |
| 143 | |
| 144 | /* FIXME: Locking. A hot pluggable device can go away |
| 145 | (del_mtd_device can be called for it) without its module |
| 146 | being unloaded. */ |
| 147 | dev->mtd->usecount++; |
| 148 | |
| 149 | ret = 0; |
| 150 | if (tr->open && (ret = tr->open(dev))) { |
| 151 | dev->mtd->usecount--; |
| 152 | put_mtd_device(dev->mtd); |
| 153 | out_tr: |
| 154 | module_put(tr->owner); |
| 155 | } |
| 156 | out: |
| 157 | return ret; |
| 158 | } |
| 159 | |
| 160 | static int blktrans_release(struct gendisk *disk, fmode_t mode) |
| 161 | { |
| 162 | struct mtd_blktrans_dev *dev = disk->private_data; |
| 163 | struct mtd_blktrans_ops *tr = dev->tr; |
| 164 | int ret = 0; |
| 165 | |
| 166 | if (tr->release) |
| 167 | ret = tr->release(dev); |
| 168 | |
| 169 | if (!ret) { |
| 170 | dev->mtd->usecount--; |
| 171 | put_mtd_device(dev->mtd); |
| 172 | module_put(tr->owner); |
| 173 | } |
| 174 | |
| 175 | return ret; |
| 176 | } |
| 177 | |
| 178 | static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) |
| 179 | { |
| 180 | struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data; |
| 181 | |
| 182 | if (dev->tr->getgeo) |
| 183 | return dev->tr->getgeo(dev, geo); |
| 184 | return -ENOTTY; |
| 185 | } |
| 186 | |
| 187 | static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, |
| 188 | unsigned int cmd, unsigned long arg) |
| 189 | { |
| 190 | struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data; |
| 191 | struct mtd_blktrans_ops *tr = dev->tr; |
| 192 | |
| 193 | switch (cmd) { |
| 194 | case BLKFLSBUF: |
| 195 | if (tr->flush) |
| 196 | return tr->flush(dev); |
| 197 | /* The core code did the work, we had nothing to do. */ |
| 198 | return 0; |
| 199 | default: |
| 200 | return -ENOTTY; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | static const struct block_device_operations mtd_blktrans_ops = { |
| 205 | .owner = THIS_MODULE, |
| 206 | .open = blktrans_open, |
| 207 | .release = blktrans_release, |
| 208 | .locked_ioctl = blktrans_ioctl, |
| 209 | .getgeo = blktrans_getgeo, |
| 210 | }; |
| 211 | |
| 212 | int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) |
| 213 | { |
| 214 | struct mtd_blktrans_ops *tr = new->tr; |
| 215 | struct mtd_blktrans_dev *d; |
| 216 | int last_devnum = -1; |
| 217 | struct gendisk *gd; |
| 218 | |
| 219 | if (mutex_trylock(&mtd_table_mutex)) { |
| 220 | mutex_unlock(&mtd_table_mutex); |
| 221 | BUG(); |
| 222 | } |
| 223 | |
| 224 | list_for_each_entry(d, &tr->devs, list) { |
| 225 | if (new->devnum == -1) { |
| 226 | /* Use first free number */ |
| 227 | if (d->devnum != last_devnum+1) { |
| 228 | /* Found a free devnum. Plug it in here */ |
| 229 | new->devnum = last_devnum+1; |
| 230 | list_add_tail(&new->list, &d->list); |
| 231 | goto added; |
| 232 | } |
| 233 | } else if (d->devnum == new->devnum) { |
| 234 | /* Required number taken */ |
| 235 | return -EBUSY; |
| 236 | } else if (d->devnum > new->devnum) { |
| 237 | /* Required number was free */ |
| 238 | list_add_tail(&new->list, &d->list); |
| 239 | goto added; |
| 240 | } |
| 241 | last_devnum = d->devnum; |
| 242 | } |
| 243 | if (new->devnum == -1) |
| 244 | new->devnum = last_devnum+1; |
| 245 | |
| 246 | if ((new->devnum << tr->part_bits) > 256) { |
| 247 | return -EBUSY; |
| 248 | } |
| 249 | |
| 250 | list_add_tail(&new->list, &tr->devs); |
| 251 | added: |
| 252 | mutex_init(&new->lock); |
| 253 | if (!tr->writesect) |
| 254 | new->readonly = 1; |
| 255 | |
| 256 | gd = alloc_disk(1 << tr->part_bits); |
| 257 | if (!gd) { |
| 258 | list_del(&new->list); |
| 259 | return -ENOMEM; |
| 260 | } |
| 261 | gd->major = tr->major; |
| 262 | gd->first_minor = (new->devnum) << tr->part_bits; |
| 263 | gd->fops = &mtd_blktrans_ops; |
| 264 | |
| 265 | if (tr->part_bits) |
| 266 | if (new->devnum < 26) |
| 267 | snprintf(gd->disk_name, sizeof(gd->disk_name), |
| 268 | "%s%c", tr->name, 'a' + new->devnum); |
| 269 | else |
| 270 | snprintf(gd->disk_name, sizeof(gd->disk_name), |
| 271 | "%s%c%c", tr->name, |
| 272 | 'a' - 1 + new->devnum / 26, |
| 273 | 'a' + new->devnum % 26); |
| 274 | else |
| 275 | snprintf(gd->disk_name, sizeof(gd->disk_name), |
| 276 | "%s%d", tr->name, new->devnum); |
| 277 | |
| 278 | /* 2.5 has capacity in units of 512 bytes while still |
| 279 | having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */ |
| 280 | set_capacity(gd, (new->size * tr->blksize) >> 9); |
| 281 | |
| 282 | gd->private_data = new; |
| 283 | new->blkcore_priv = gd; |
| 284 | gd->queue = tr->blkcore_priv->rq; |
| 285 | gd->driverfs_dev = &new->mtd->dev; |
| 286 | |
| 287 | if (new->readonly) |
| 288 | set_disk_ro(gd, 1); |
| 289 | |
| 290 | add_disk(gd); |
| 291 | |
| 292 | return 0; |
| 293 | } |
| 294 | |
| 295 | int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) |
| 296 | { |
| 297 | if (mutex_trylock(&mtd_table_mutex)) { |
| 298 | mutex_unlock(&mtd_table_mutex); |
| 299 | BUG(); |
| 300 | } |
| 301 | |
| 302 | list_del(&old->list); |
| 303 | |
| 304 | del_gendisk(old->blkcore_priv); |
| 305 | put_disk(old->blkcore_priv); |
| 306 | |
| 307 | return 0; |
| 308 | } |
| 309 | |
| 310 | static void blktrans_notify_remove(struct mtd_info *mtd) |
| 311 | { |
| 312 | struct mtd_blktrans_ops *tr; |
| 313 | struct mtd_blktrans_dev *dev, *next; |
| 314 | |
| 315 | list_for_each_entry(tr, &blktrans_majors, list) |
| 316 | list_for_each_entry_safe(dev, next, &tr->devs, list) |
| 317 | if (dev->mtd == mtd) |
| 318 | tr->remove_dev(dev); |
| 319 | } |
| 320 | |
| 321 | static void blktrans_notify_add(struct mtd_info *mtd) |
| 322 | { |
| 323 | struct mtd_blktrans_ops *tr; |
| 324 | |
| 325 | if (mtd->type == MTD_ABSENT) |
| 326 | return; |
| 327 | |
| 328 | list_for_each_entry(tr, &blktrans_majors, list) |
| 329 | tr->add_mtd(tr, mtd); |
| 330 | } |
| 331 | |
| 332 | static struct mtd_notifier blktrans_notifier = { |
| 333 | .add = blktrans_notify_add, |
| 334 | .remove = blktrans_notify_remove, |
| 335 | }; |
| 336 | |
| 337 | int register_mtd_blktrans(struct mtd_blktrans_ops *tr) |
| 338 | { |
| 339 | int ret, i; |
| 340 | |
| 341 | /* Register the notifier if/when the first device type is |
| 342 | registered, to prevent the link/init ordering from fucking |
| 343 | us over. */ |
| 344 | if (!blktrans_notifier.list.next) |
| 345 | register_mtd_user(&blktrans_notifier); |
| 346 | |
| 347 | tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL); |
| 348 | if (!tr->blkcore_priv) |
| 349 | return -ENOMEM; |
| 350 | |
| 351 | mutex_lock(&mtd_table_mutex); |
| 352 | |
| 353 | ret = register_blkdev(tr->major, tr->name); |
| 354 | if (ret) { |
| 355 | printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", |
| 356 | tr->name, tr->major, ret); |
| 357 | kfree(tr->blkcore_priv); |
| 358 | mutex_unlock(&mtd_table_mutex); |
| 359 | return ret; |
| 360 | } |
| 361 | spin_lock_init(&tr->blkcore_priv->queue_lock); |
| 362 | |
| 363 | tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock); |
| 364 | if (!tr->blkcore_priv->rq) { |
| 365 | unregister_blkdev(tr->major, tr->name); |
| 366 | kfree(tr->blkcore_priv); |
| 367 | mutex_unlock(&mtd_table_mutex); |
| 368 | return -ENOMEM; |
| 369 | } |
| 370 | |
| 371 | tr->blkcore_priv->rq->queuedata = tr; |
| 372 | blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize); |
| 373 | if (tr->discard) |
| 374 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, |
| 375 | tr->blkcore_priv->rq); |
| 376 | |
| 377 | tr->blkshift = ffs(tr->blksize) - 1; |
| 378 | |
| 379 | tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr, |
| 380 | "%sd", tr->name); |
| 381 | if (IS_ERR(tr->blkcore_priv->thread)) { |
| 382 | int ret = PTR_ERR(tr->blkcore_priv->thread); |
| 383 | blk_cleanup_queue(tr->blkcore_priv->rq); |
| 384 | unregister_blkdev(tr->major, tr->name); |
| 385 | kfree(tr->blkcore_priv); |
| 386 | mutex_unlock(&mtd_table_mutex); |
| 387 | return ret; |
| 388 | } |
| 389 | |
| 390 | INIT_LIST_HEAD(&tr->devs); |
| 391 | list_add(&tr->list, &blktrans_majors); |
| 392 | |
| 393 | for (i=0; i<MAX_MTD_DEVICES; i++) { |
| 394 | if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT) |
| 395 | tr->add_mtd(tr, mtd_table[i]); |
| 396 | } |
| 397 | |
| 398 | mutex_unlock(&mtd_table_mutex); |
| 399 | |
| 400 | return 0; |
| 401 | } |
| 402 | |
| 403 | int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) |
| 404 | { |
| 405 | struct mtd_blktrans_dev *dev, *next; |
| 406 | |
| 407 | mutex_lock(&mtd_table_mutex); |
| 408 | |
| 409 | /* Clean up the kernel thread */ |
| 410 | kthread_stop(tr->blkcore_priv->thread); |
| 411 | |
| 412 | /* Remove it from the list of active majors */ |
| 413 | list_del(&tr->list); |
| 414 | |
| 415 | list_for_each_entry_safe(dev, next, &tr->devs, list) |
| 416 | tr->remove_dev(dev); |
| 417 | |
| 418 | blk_cleanup_queue(tr->blkcore_priv->rq); |
| 419 | unregister_blkdev(tr->major, tr->name); |
| 420 | |
| 421 | mutex_unlock(&mtd_table_mutex); |
| 422 | |
| 423 | kfree(tr->blkcore_priv); |
| 424 | |
| 425 | BUG_ON(!list_empty(&tr->devs)); |
| 426 | return 0; |
| 427 | } |
| 428 | |
| 429 | static void __exit mtd_blktrans_exit(void) |
| 430 | { |
| 431 | /* No race here -- if someone's currently in register_mtd_blktrans |
| 432 | we're screwed anyway. */ |
| 433 | if (blktrans_notifier.list.next) |
| 434 | unregister_mtd_user(&blktrans_notifier); |
| 435 | } |
| 436 | |
| 437 | module_exit(mtd_blktrans_exit); |
| 438 | |
| 439 | EXPORT_SYMBOL_GPL(register_mtd_blktrans); |
| 440 | EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); |
| 441 | EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); |
| 442 | EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); |
| 443 | |
| 444 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); |
| 445 | MODULE_LICENSE("GPL"); |
| 446 | MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); |