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