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))
68 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
69 if (tr->writesect(dev, block, buf))
74 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
79 static int mtd_blktrans_thread(void *arg)
81 struct mtd_blktrans_ops *tr = arg;
82 struct request_queue *rq = tr->blkcore_priv->rq;
83 struct request *req = NULL;
85 /* we might get involved when memory gets low, so use PF_MEMALLOC */
86 current->flags |= PF_MEMALLOC;
88 spin_lock_irq(rq->queue_lock);
90 while (!kthread_should_stop()) {
91 struct mtd_blktrans_dev *dev;
94 if (!req && !(req = blk_fetch_request(rq))) {
95 set_current_state(TASK_INTERRUPTIBLE);
96 spin_unlock_irq(rq->queue_lock);
98 spin_lock_irq(rq->queue_lock);
102 dev = req->rq_disk->private_data;
105 spin_unlock_irq(rq->queue_lock);
107 mutex_lock(&dev->lock);
108 res = do_blktrans_request(tr, dev, req);
109 mutex_unlock(&dev->lock);
111 spin_lock_irq(rq->queue_lock);
113 if (!__blk_end_request_cur(req, res))
118 __blk_end_request_all(req, -EIO);
120 spin_unlock_irq(rq->queue_lock);
125 static void mtd_blktrans_request(struct request_queue *rq)
127 struct mtd_blktrans_ops *tr = rq->queuedata;
128 wake_up_process(tr->blkcore_priv->thread);
132 static int blktrans_open(struct block_device *bdev, fmode_t mode)
134 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
135 struct mtd_blktrans_ops *tr = dev->tr;
138 if (!get_mtd_device(NULL, dev->mtd->index))
141 if (!try_module_get(tr->owner))
144 /* FIXME: Locking. A hot pluggable device can go away
145 (del_mtd_device can be called for it) without its module
147 dev->mtd->usecount++;
150 if (tr->open && (ret = tr->open(dev))) {
151 dev->mtd->usecount--;
152 put_mtd_device(dev->mtd);
154 module_put(tr->owner);
160 static int blktrans_release(struct gendisk *disk, fmode_t mode)
162 struct mtd_blktrans_dev *dev = disk->private_data;
163 struct mtd_blktrans_ops *tr = dev->tr;
167 ret = tr->release(dev);
170 dev->mtd->usecount--;
171 put_mtd_device(dev->mtd);
172 module_put(tr->owner);
178 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
180 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
183 return dev->tr->getgeo(dev, geo);
187 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
188 unsigned int cmd, unsigned long arg)
190 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
191 struct mtd_blktrans_ops *tr = dev->tr;
196 return tr->flush(dev);
197 /* The core code did the work, we had nothing to do. */
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,
212 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
214 struct mtd_blktrans_ops *tr = new->tr;
215 struct mtd_blktrans_dev *d;
216 int last_devnum = -1;
219 if (mutex_trylock(&mtd_table_mutex)) {
220 mutex_unlock(&mtd_table_mutex);
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);
233 } else if (d->devnum == new->devnum) {
234 /* Required number taken */
236 } else if (d->devnum > new->devnum) {
237 /* Required number was free */
238 list_add_tail(&new->list, &d->list);
241 last_devnum = d->devnum;
243 if (new->devnum == -1)
244 new->devnum = last_devnum+1;
246 if ((new->devnum << tr->part_bits) > 256) {
250 list_add_tail(&new->list, &tr->devs);
252 mutex_init(&new->lock);
256 gd = alloc_disk(1 << tr->part_bits);
258 list_del(&new->list);
261 gd->major = tr->major;
262 gd->first_minor = (new->devnum) << tr->part_bits;
263 gd->fops = &mtd_blktrans_ops;
266 if (new->devnum < 26)
267 snprintf(gd->disk_name, sizeof(gd->disk_name),
268 "%s%c", tr->name, 'a' + new->devnum);
270 snprintf(gd->disk_name, sizeof(gd->disk_name),
272 'a' - 1 + new->devnum / 26,
273 'a' + new->devnum % 26);
275 snprintf(gd->disk_name, sizeof(gd->disk_name),
276 "%s%d", tr->name, new->devnum);
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);
282 gd->private_data = new;
283 new->blkcore_priv = gd;
284 gd->queue = tr->blkcore_priv->rq;
285 gd->driverfs_dev = &new->mtd->dev;
295 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
297 if (mutex_trylock(&mtd_table_mutex)) {
298 mutex_unlock(&mtd_table_mutex);
302 list_del(&old->list);
304 del_gendisk(old->blkcore_priv);
305 put_disk(old->blkcore_priv);
310 static void blktrans_notify_remove(struct mtd_info *mtd)
312 struct mtd_blktrans_ops *tr;
313 struct mtd_blktrans_dev *dev, *next;
315 list_for_each_entry(tr, &blktrans_majors, list)
316 list_for_each_entry_safe(dev, next, &tr->devs, list)
321 static void blktrans_notify_add(struct mtd_info *mtd)
323 struct mtd_blktrans_ops *tr;
325 if (mtd->type == MTD_ABSENT)
328 list_for_each_entry(tr, &blktrans_majors, list)
329 tr->add_mtd(tr, mtd);
332 static struct mtd_notifier blktrans_notifier = {
333 .add = blktrans_notify_add,
334 .remove = blktrans_notify_remove,
337 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
341 /* Register the notifier if/when the first device type is
342 registered, to prevent the link/init ordering from fucking
344 if (!blktrans_notifier.list.next)
345 register_mtd_user(&blktrans_notifier);
347 tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
348 if (!tr->blkcore_priv)
351 mutex_lock(&mtd_table_mutex);
353 ret = register_blkdev(tr->major, tr->name);
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);
361 spin_lock_init(&tr->blkcore_priv->queue_lock);
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);
371 tr->blkcore_priv->rq->queuedata = tr;
372 blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
374 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
375 tr->blkcore_priv->rq);
377 tr->blkshift = ffs(tr->blksize) - 1;
379 tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
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);
390 INIT_LIST_HEAD(&tr->devs);
391 list_add(&tr->list, &blktrans_majors);
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]);
398 mutex_unlock(&mtd_table_mutex);
403 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
405 struct mtd_blktrans_dev *dev, *next;
407 mutex_lock(&mtd_table_mutex);
409 /* Clean up the kernel thread */
410 kthread_stop(tr->blkcore_priv->thread);
412 /* Remove it from the list of active majors */
415 list_for_each_entry_safe(dev, next, &tr->devs, list)
418 blk_cleanup_queue(tr->blkcore_priv->rq);
419 unregister_blkdev(tr->major, tr->name);
421 mutex_unlock(&mtd_table_mutex);
423 kfree(tr->blkcore_priv);
425 BUG_ON(!list_empty(&tr->devs));
429 static void __exit mtd_blktrans_exit(void)
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);
437 module_exit(mtd_blktrans_exit);
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);
444 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
445 MODULE_LICENSE("GPL");
446 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");