2 * (C) 2003 David Woodhouse <dwmw2@infradead.org>
4 * Interface to Linux 2.5 block layer for MTD 'translation layers'.
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 #include <linux/list.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>
27 static LIST_HEAD(blktrans_majors);
29 struct mtd_blkcore_priv {
30 struct task_struct *thread;
31 struct request_queue *rq;
32 spinlock_t queue_lock;
35 static int blktrans_discard_request(struct request_queue *q,
38 req->cmd_type = REQ_TYPE_LINUX_BLOCK;
39 req->cmd[0] = REQ_LB_OP_DISCARD;
43 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
44 struct mtd_blktrans_dev *dev,
47 unsigned long block, nsect;
50 block = blk_rq_pos(req) << 9 >> tr->blkshift;
51 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
55 if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
56 req->cmd[0] == REQ_LB_OP_DISCARD)
57 return tr->discard(dev, block, nsect);
59 if (!blk_fs_request(req))
62 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
63 get_capacity(req->rq_disk))
66 switch(rq_data_dir(req)) {
68 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
69 if (tr->readsect(dev, block, buf))
77 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
78 if (tr->writesect(dev, block, buf))
83 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
88 static int mtd_blktrans_thread(void *arg)
90 struct mtd_blktrans_ops *tr = arg;
91 struct request_queue *rq = tr->blkcore_priv->rq;
92 struct request *req = NULL;
94 /* we might get involved when memory gets low, so use PF_MEMALLOC */
95 current->flags |= PF_MEMALLOC;
97 spin_lock_irq(rq->queue_lock);
99 while (!kthread_should_stop()) {
100 struct mtd_blktrans_dev *dev;
104 req = elv_next_request(rq);
106 blkdev_dequeue_request(req);
109 set_current_state(TASK_INTERRUPTIBLE);
110 spin_unlock_irq(rq->queue_lock);
112 spin_lock_irq(rq->queue_lock);
116 dev = req->rq_disk->private_data;
119 spin_unlock_irq(rq->queue_lock);
121 mutex_lock(&dev->lock);
122 res = do_blktrans_request(tr, dev, req);
123 mutex_unlock(&dev->lock);
125 spin_lock_irq(rq->queue_lock);
127 if (!__blk_end_request_cur(req, res))
132 __blk_end_request_all(req, -EIO);
134 spin_unlock_irq(rq->queue_lock);
139 static void mtd_blktrans_request(struct request_queue *rq)
141 struct mtd_blktrans_ops *tr = rq->queuedata;
142 wake_up_process(tr->blkcore_priv->thread);
146 static int blktrans_open(struct block_device *bdev, fmode_t mode)
148 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
149 struct mtd_blktrans_ops *tr = dev->tr;
152 if (!try_module_get(dev->mtd->owner))
155 if (!try_module_get(tr->owner))
158 /* FIXME: Locking. A hot pluggable device can go away
159 (del_mtd_device can be called for it) without its module
161 dev->mtd->usecount++;
164 if (tr->open && (ret = tr->open(dev))) {
165 dev->mtd->usecount--;
166 module_put(dev->mtd->owner);
168 module_put(tr->owner);
174 static int blktrans_release(struct gendisk *disk, fmode_t mode)
176 struct mtd_blktrans_dev *dev = disk->private_data;
177 struct mtd_blktrans_ops *tr = dev->tr;
181 ret = tr->release(dev);
184 dev->mtd->usecount--;
185 module_put(dev->mtd->owner);
186 module_put(tr->owner);
192 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
194 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
197 return dev->tr->getgeo(dev, geo);
201 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
202 unsigned int cmd, unsigned long arg)
204 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
205 struct mtd_blktrans_ops *tr = dev->tr;
210 return tr->flush(dev);
211 /* The core code did the work, we had nothing to do. */
218 static struct block_device_operations mtd_blktrans_ops = {
219 .owner = THIS_MODULE,
220 .open = blktrans_open,
221 .release = blktrans_release,
222 .locked_ioctl = blktrans_ioctl,
223 .getgeo = blktrans_getgeo,
226 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
228 struct mtd_blktrans_ops *tr = new->tr;
229 struct mtd_blktrans_dev *d;
230 int last_devnum = -1;
233 if (mutex_trylock(&mtd_table_mutex)) {
234 mutex_unlock(&mtd_table_mutex);
238 list_for_each_entry(d, &tr->devs, list) {
239 if (new->devnum == -1) {
240 /* Use first free number */
241 if (d->devnum != last_devnum+1) {
242 /* Found a free devnum. Plug it in here */
243 new->devnum = last_devnum+1;
244 list_add_tail(&new->list, &d->list);
247 } else if (d->devnum == new->devnum) {
248 /* Required number taken */
250 } else if (d->devnum > new->devnum) {
251 /* Required number was free */
252 list_add_tail(&new->list, &d->list);
255 last_devnum = d->devnum;
257 if (new->devnum == -1)
258 new->devnum = last_devnum+1;
260 if ((new->devnum << tr->part_bits) > 256) {
264 list_add_tail(&new->list, &tr->devs);
266 mutex_init(&new->lock);
270 gd = alloc_disk(1 << tr->part_bits);
272 list_del(&new->list);
275 gd->major = tr->major;
276 gd->first_minor = (new->devnum) << tr->part_bits;
277 gd->fops = &mtd_blktrans_ops;
280 if (new->devnum < 26)
281 snprintf(gd->disk_name, sizeof(gd->disk_name),
282 "%s%c", tr->name, 'a' + new->devnum);
284 snprintf(gd->disk_name, sizeof(gd->disk_name),
286 'a' - 1 + new->devnum / 26,
287 'a' + new->devnum % 26);
289 snprintf(gd->disk_name, sizeof(gd->disk_name),
290 "%s%d", tr->name, new->devnum);
292 /* 2.5 has capacity in units of 512 bytes while still
293 having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
294 set_capacity(gd, (new->size * tr->blksize) >> 9);
296 gd->private_data = new;
297 new->blkcore_priv = gd;
298 gd->queue = tr->blkcore_priv->rq;
299 gd->driverfs_dev = new->mtd->dev.parent;
309 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
311 if (mutex_trylock(&mtd_table_mutex)) {
312 mutex_unlock(&mtd_table_mutex);
316 list_del(&old->list);
318 del_gendisk(old->blkcore_priv);
319 put_disk(old->blkcore_priv);
324 static void blktrans_notify_remove(struct mtd_info *mtd)
326 struct mtd_blktrans_ops *tr;
327 struct mtd_blktrans_dev *dev, *next;
329 list_for_each_entry(tr, &blktrans_majors, list)
330 list_for_each_entry_safe(dev, next, &tr->devs, list)
335 static void blktrans_notify_add(struct mtd_info *mtd)
337 struct mtd_blktrans_ops *tr;
339 if (mtd->type == MTD_ABSENT)
342 list_for_each_entry(tr, &blktrans_majors, list)
343 tr->add_mtd(tr, mtd);
346 static struct mtd_notifier blktrans_notifier = {
347 .add = blktrans_notify_add,
348 .remove = blktrans_notify_remove,
351 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
355 /* Register the notifier if/when the first device type is
356 registered, to prevent the link/init ordering from fucking
358 if (!blktrans_notifier.list.next)
359 register_mtd_user(&blktrans_notifier);
361 tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
362 if (!tr->blkcore_priv)
365 mutex_lock(&mtd_table_mutex);
367 ret = register_blkdev(tr->major, tr->name);
369 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
370 tr->name, tr->major, ret);
371 kfree(tr->blkcore_priv);
372 mutex_unlock(&mtd_table_mutex);
375 spin_lock_init(&tr->blkcore_priv->queue_lock);
377 tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
378 if (!tr->blkcore_priv->rq) {
379 unregister_blkdev(tr->major, tr->name);
380 kfree(tr->blkcore_priv);
381 mutex_unlock(&mtd_table_mutex);
385 tr->blkcore_priv->rq->queuedata = tr;
386 blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
388 blk_queue_set_discard(tr->blkcore_priv->rq,
389 blktrans_discard_request);
391 tr->blkshift = ffs(tr->blksize) - 1;
393 tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
395 if (IS_ERR(tr->blkcore_priv->thread)) {
396 int ret = PTR_ERR(tr->blkcore_priv->thread);
397 blk_cleanup_queue(tr->blkcore_priv->rq);
398 unregister_blkdev(tr->major, tr->name);
399 kfree(tr->blkcore_priv);
400 mutex_unlock(&mtd_table_mutex);
404 INIT_LIST_HEAD(&tr->devs);
405 list_add(&tr->list, &blktrans_majors);
407 for (i=0; i<MAX_MTD_DEVICES; i++) {
408 if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
409 tr->add_mtd(tr, mtd_table[i]);
412 mutex_unlock(&mtd_table_mutex);
417 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
419 struct mtd_blktrans_dev *dev, *next;
421 mutex_lock(&mtd_table_mutex);
423 /* Clean up the kernel thread */
424 kthread_stop(tr->blkcore_priv->thread);
426 /* Remove it from the list of active majors */
429 list_for_each_entry_safe(dev, next, &tr->devs, list)
432 blk_cleanup_queue(tr->blkcore_priv->rq);
433 unregister_blkdev(tr->major, tr->name);
435 mutex_unlock(&mtd_table_mutex);
437 kfree(tr->blkcore_priv);
439 BUG_ON(!list_empty(&tr->devs));
443 static void __exit mtd_blktrans_exit(void)
445 /* No race here -- if someone's currently in register_mtd_blktrans
446 we're screwed anyway. */
447 if (blktrans_notifier.list.next)
448 unregister_mtd_user(&blktrans_notifier);
451 module_exit(mtd_blktrans_exit);
453 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
454 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
455 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
456 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
458 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
459 MODULE_LICENSE("GPL");
460 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");