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 do_blktrans_request(struct mtd_blktrans_ops *tr,
36 struct mtd_blktrans_dev *dev,
39 unsigned long block, nsect;
42 block = blk_rq_pos(req) << 9 >> tr->blkshift;
43 nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
47 if (!blk_fs_request(req))
50 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
51 get_capacity(req->rq_disk))
54 if (blk_discard_rq(req))
55 return tr->discard(dev, block, nsect);
57 switch(rq_data_dir(req)) {
59 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
60 if (tr->readsect(dev, block, buf))
62 rq_flush_dcache_pages(req);
69 rq_flush_dcache_pages(req);
70 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
71 if (tr->writesect(dev, block, buf))
76 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
81 static int mtd_blktrans_thread(void *arg)
83 struct mtd_blktrans_ops *tr = arg;
84 struct request_queue *rq = tr->blkcore_priv->rq;
85 struct request *req = NULL;
87 spin_lock_irq(rq->queue_lock);
89 while (!kthread_should_stop()) {
90 struct mtd_blktrans_dev *dev;
93 if (!req && !(req = blk_fetch_request(rq))) {
94 set_current_state(TASK_INTERRUPTIBLE);
95 spin_unlock_irq(rq->queue_lock);
97 spin_lock_irq(rq->queue_lock);
101 dev = req->rq_disk->private_data;
104 spin_unlock_irq(rq->queue_lock);
106 mutex_lock(&dev->lock);
107 res = do_blktrans_request(tr, dev, req);
108 mutex_unlock(&dev->lock);
110 spin_lock_irq(rq->queue_lock);
112 if (!__blk_end_request_cur(req, res))
117 __blk_end_request_all(req, -EIO);
119 spin_unlock_irq(rq->queue_lock);
124 static void mtd_blktrans_request(struct request_queue *rq)
126 struct mtd_blktrans_ops *tr = rq->queuedata;
127 wake_up_process(tr->blkcore_priv->thread);
131 static int blktrans_open(struct block_device *bdev, fmode_t mode)
133 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
134 struct mtd_blktrans_ops *tr = dev->tr;
137 if (!get_mtd_device(NULL, dev->mtd->index))
140 if (!try_module_get(tr->owner))
143 /* FIXME: Locking. A hot pluggable device can go away
144 (del_mtd_device can be called for it) without its module
146 dev->mtd->usecount++;
149 if (tr->open && (ret = tr->open(dev))) {
150 dev->mtd->usecount--;
151 put_mtd_device(dev->mtd);
153 module_put(tr->owner);
159 static int blktrans_release(struct gendisk *disk, fmode_t mode)
161 struct mtd_blktrans_dev *dev = disk->private_data;
162 struct mtd_blktrans_ops *tr = dev->tr;
166 ret = tr->release(dev);
169 dev->mtd->usecount--;
170 put_mtd_device(dev->mtd);
171 module_put(tr->owner);
177 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
179 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
182 return dev->tr->getgeo(dev, geo);
186 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
187 unsigned int cmd, unsigned long arg)
189 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
190 struct mtd_blktrans_ops *tr = dev->tr;
195 return tr->flush(dev);
196 /* The core code did the work, we had nothing to do. */
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,
211 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
213 struct mtd_blktrans_ops *tr = new->tr;
214 struct mtd_blktrans_dev *d;
215 int last_devnum = -1;
218 if (mutex_trylock(&mtd_table_mutex)) {
219 mutex_unlock(&mtd_table_mutex);
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);
232 } else if (d->devnum == new->devnum) {
233 /* Required number taken */
235 } else if (d->devnum > new->devnum) {
236 /* Required number was free */
237 list_add_tail(&new->list, &d->list);
240 last_devnum = d->devnum;
242 if (new->devnum == -1)
243 new->devnum = last_devnum+1;
245 /* Check that the device and any partitions will get valid
246 * minor numbers and that the disk naming code below can cope
247 * with this number. */
248 if (new->devnum > (MINORMASK >> tr->part_bits) ||
249 (tr->part_bits && new->devnum >= 27 * 26))
252 list_add_tail(&new->list, &tr->devs);
254 mutex_init(&new->lock);
258 gd = alloc_disk(1 << tr->part_bits);
260 list_del(&new->list);
263 gd->major = tr->major;
264 gd->first_minor = (new->devnum) << tr->part_bits;
265 gd->fops = &mtd_blktrans_ops;
268 if (new->devnum < 26)
269 snprintf(gd->disk_name, sizeof(gd->disk_name),
270 "%s%c", tr->name, 'a' + new->devnum);
272 snprintf(gd->disk_name, sizeof(gd->disk_name),
274 'a' - 1 + new->devnum / 26,
275 'a' + new->devnum % 26);
277 snprintf(gd->disk_name, sizeof(gd->disk_name),
278 "%s%d", tr->name, new->devnum);
280 /* 2.5 has capacity in units of 512 bytes while still
281 having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
282 set_capacity(gd, (new->size * tr->blksize) >> 9);
284 gd->private_data = new;
285 new->blkcore_priv = gd;
286 gd->queue = tr->blkcore_priv->rq;
287 gd->driverfs_dev = &new->mtd->dev;
297 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
299 if (mutex_trylock(&mtd_table_mutex)) {
300 mutex_unlock(&mtd_table_mutex);
304 list_del(&old->list);
306 del_gendisk(old->blkcore_priv);
307 put_disk(old->blkcore_priv);
312 static void blktrans_notify_remove(struct mtd_info *mtd)
314 struct mtd_blktrans_ops *tr;
315 struct mtd_blktrans_dev *dev, *next;
317 list_for_each_entry(tr, &blktrans_majors, list)
318 list_for_each_entry_safe(dev, next, &tr->devs, list)
323 static void blktrans_notify_add(struct mtd_info *mtd)
325 struct mtd_blktrans_ops *tr;
327 if (mtd->type == MTD_ABSENT)
330 list_for_each_entry(tr, &blktrans_majors, list)
331 tr->add_mtd(tr, mtd);
334 static struct mtd_notifier blktrans_notifier = {
335 .add = blktrans_notify_add,
336 .remove = blktrans_notify_remove,
339 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
341 struct mtd_info *mtd;
344 /* Register the notifier if/when the first device type is
345 registered, to prevent the link/init ordering from fucking
347 if (!blktrans_notifier.list.next)
348 register_mtd_user(&blktrans_notifier);
350 tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
351 if (!tr->blkcore_priv)
354 mutex_lock(&mtd_table_mutex);
356 ret = register_blkdev(tr->major, tr->name);
358 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
359 tr->name, tr->major, ret);
360 kfree(tr->blkcore_priv);
361 mutex_unlock(&mtd_table_mutex);
364 spin_lock_init(&tr->blkcore_priv->queue_lock);
366 tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
367 if (!tr->blkcore_priv->rq) {
368 unregister_blkdev(tr->major, tr->name);
369 kfree(tr->blkcore_priv);
370 mutex_unlock(&mtd_table_mutex);
374 tr->blkcore_priv->rq->queuedata = tr;
375 blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
377 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
378 tr->blkcore_priv->rq);
380 tr->blkshift = ffs(tr->blksize) - 1;
382 tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
384 if (IS_ERR(tr->blkcore_priv->thread)) {
385 ret = PTR_ERR(tr->blkcore_priv->thread);
386 blk_cleanup_queue(tr->blkcore_priv->rq);
387 unregister_blkdev(tr->major, tr->name);
388 kfree(tr->blkcore_priv);
389 mutex_unlock(&mtd_table_mutex);
393 INIT_LIST_HEAD(&tr->devs);
394 list_add(&tr->list, &blktrans_majors);
396 mtd_for_each_device(mtd)
397 if (mtd->type != MTD_ABSENT)
398 tr->add_mtd(tr, mtd);
400 mutex_unlock(&mtd_table_mutex);
405 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
407 struct mtd_blktrans_dev *dev, *next;
409 mutex_lock(&mtd_table_mutex);
411 /* Clean up the kernel thread */
412 kthread_stop(tr->blkcore_priv->thread);
414 /* Remove it from the list of active majors */
417 list_for_each_entry_safe(dev, next, &tr->devs, list)
420 blk_cleanup_queue(tr->blkcore_priv->rq);
421 unregister_blkdev(tr->major, tr->name);
423 mutex_unlock(&mtd_table_mutex);
425 kfree(tr->blkcore_priv);
427 BUG_ON(!list_empty(&tr->devs));
431 static void __exit mtd_blktrans_exit(void)
433 /* No race here -- if someone's currently in register_mtd_blktrans
434 we're screwed anyway. */
435 if (blktrans_notifier.list.next)
436 unregister_mtd_user(&blktrans_notifier);
439 module_exit(mtd_blktrans_exit);
441 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
442 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
443 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
444 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
446 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
447 MODULE_LICENSE("GPL");
448 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");