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 spin_lock_irq(rq->queue_lock);
96 while (!kthread_should_stop()) {
97 struct mtd_blktrans_dev *dev;
100 if (!req && !(req = blk_fetch_request(rq))) {
101 set_current_state(TASK_INTERRUPTIBLE);
102 spin_unlock_irq(rq->queue_lock);
104 spin_lock_irq(rq->queue_lock);
108 dev = req->rq_disk->private_data;
111 spin_unlock_irq(rq->queue_lock);
113 mutex_lock(&dev->lock);
114 res = do_blktrans_request(tr, dev, req);
115 mutex_unlock(&dev->lock);
117 spin_lock_irq(rq->queue_lock);
119 if (!__blk_end_request_cur(req, res))
124 __blk_end_request_all(req, -EIO);
126 spin_unlock_irq(rq->queue_lock);
131 static void mtd_blktrans_request(struct request_queue *rq)
133 struct mtd_blktrans_ops *tr = rq->queuedata;
134 wake_up_process(tr->blkcore_priv->thread);
138 static int blktrans_open(struct block_device *bdev, fmode_t mode)
140 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
141 struct mtd_blktrans_ops *tr = dev->tr;
144 if (!get_mtd_device(NULL, dev->mtd->index))
147 if (!try_module_get(tr->owner))
150 /* FIXME: Locking. A hot pluggable device can go away
151 (del_mtd_device can be called for it) without its module
153 dev->mtd->usecount++;
156 if (tr->open && (ret = tr->open(dev))) {
157 dev->mtd->usecount--;
158 put_mtd_device(dev->mtd);
160 module_put(tr->owner);
166 static int blktrans_release(struct gendisk *disk, fmode_t mode)
168 struct mtd_blktrans_dev *dev = disk->private_data;
169 struct mtd_blktrans_ops *tr = dev->tr;
173 ret = tr->release(dev);
176 dev->mtd->usecount--;
177 put_mtd_device(dev->mtd);
178 module_put(tr->owner);
184 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
186 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
189 return dev->tr->getgeo(dev, geo);
193 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
194 unsigned int cmd, unsigned long arg)
196 struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
197 struct mtd_blktrans_ops *tr = dev->tr;
202 return tr->flush(dev);
203 /* The core code did the work, we had nothing to do. */
210 static const struct block_device_operations mtd_blktrans_ops = {
211 .owner = THIS_MODULE,
212 .open = blktrans_open,
213 .release = blktrans_release,
214 .locked_ioctl = blktrans_ioctl,
215 .getgeo = blktrans_getgeo,
218 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
220 struct mtd_blktrans_ops *tr = new->tr;
221 struct mtd_blktrans_dev *d;
222 int last_devnum = -1;
225 if (mutex_trylock(&mtd_table_mutex)) {
226 mutex_unlock(&mtd_table_mutex);
230 list_for_each_entry(d, &tr->devs, list) {
231 if (new->devnum == -1) {
232 /* Use first free number */
233 if (d->devnum != last_devnum+1) {
234 /* Found a free devnum. Plug it in here */
235 new->devnum = last_devnum+1;
236 list_add_tail(&new->list, &d->list);
239 } else if (d->devnum == new->devnum) {
240 /* Required number taken */
242 } else if (d->devnum > new->devnum) {
243 /* Required number was free */
244 list_add_tail(&new->list, &d->list);
247 last_devnum = d->devnum;
249 if (new->devnum == -1)
250 new->devnum = last_devnum+1;
252 if ((new->devnum << tr->part_bits) > 256) {
256 list_add_tail(&new->list, &tr->devs);
258 mutex_init(&new->lock);
262 gd = alloc_disk(1 << tr->part_bits);
264 list_del(&new->list);
267 gd->major = tr->major;
268 gd->first_minor = (new->devnum) << tr->part_bits;
269 gd->fops = &mtd_blktrans_ops;
272 if (new->devnum < 26)
273 snprintf(gd->disk_name, sizeof(gd->disk_name),
274 "%s%c", tr->name, 'a' + new->devnum);
276 snprintf(gd->disk_name, sizeof(gd->disk_name),
278 'a' - 1 + new->devnum / 26,
279 'a' + new->devnum % 26);
281 snprintf(gd->disk_name, sizeof(gd->disk_name),
282 "%s%d", tr->name, new->devnum);
284 /* 2.5 has capacity in units of 512 bytes while still
285 having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
286 set_capacity(gd, (new->size * tr->blksize) >> 9);
288 gd->private_data = new;
289 new->blkcore_priv = gd;
290 gd->queue = tr->blkcore_priv->rq;
291 gd->driverfs_dev = &new->mtd->dev;
301 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
303 if (mutex_trylock(&mtd_table_mutex)) {
304 mutex_unlock(&mtd_table_mutex);
308 list_del(&old->list);
310 del_gendisk(old->blkcore_priv);
311 put_disk(old->blkcore_priv);
316 static void blktrans_notify_remove(struct mtd_info *mtd)
318 struct mtd_blktrans_ops *tr;
319 struct mtd_blktrans_dev *dev, *next;
321 list_for_each_entry(tr, &blktrans_majors, list)
322 list_for_each_entry_safe(dev, next, &tr->devs, list)
327 static void blktrans_notify_add(struct mtd_info *mtd)
329 struct mtd_blktrans_ops *tr;
331 if (mtd->type == MTD_ABSENT)
334 list_for_each_entry(tr, &blktrans_majors, list)
335 tr->add_mtd(tr, mtd);
338 static struct mtd_notifier blktrans_notifier = {
339 .add = blktrans_notify_add,
340 .remove = blktrans_notify_remove,
343 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
347 /* Register the notifier if/when the first device type is
348 registered, to prevent the link/init ordering from fucking
350 if (!blktrans_notifier.list.next)
351 register_mtd_user(&blktrans_notifier);
353 tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
354 if (!tr->blkcore_priv)
357 mutex_lock(&mtd_table_mutex);
359 ret = register_blkdev(tr->major, tr->name);
361 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
362 tr->name, tr->major, ret);
363 kfree(tr->blkcore_priv);
364 mutex_unlock(&mtd_table_mutex);
367 spin_lock_init(&tr->blkcore_priv->queue_lock);
369 tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
370 if (!tr->blkcore_priv->rq) {
371 unregister_blkdev(tr->major, tr->name);
372 kfree(tr->blkcore_priv);
373 mutex_unlock(&mtd_table_mutex);
377 tr->blkcore_priv->rq->queuedata = tr;
378 blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
380 blk_queue_set_discard(tr->blkcore_priv->rq,
381 blktrans_discard_request);
383 tr->blkshift = ffs(tr->blksize) - 1;
385 tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
387 if (IS_ERR(tr->blkcore_priv->thread)) {
388 ret = PTR_ERR(tr->blkcore_priv->thread);
389 blk_cleanup_queue(tr->blkcore_priv->rq);
390 unregister_blkdev(tr->major, tr->name);
391 kfree(tr->blkcore_priv);
392 mutex_unlock(&mtd_table_mutex);
396 INIT_LIST_HEAD(&tr->devs);
397 list_add(&tr->list, &blktrans_majors);
399 for (i=0; i<MAX_MTD_DEVICES; i++) {
400 if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
401 tr->add_mtd(tr, mtd_table[i]);
404 mutex_unlock(&mtd_table_mutex);
409 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
411 struct mtd_blktrans_dev *dev, *next;
413 mutex_lock(&mtd_table_mutex);
415 /* Clean up the kernel thread */
416 kthread_stop(tr->blkcore_priv->thread);
418 /* Remove it from the list of active majors */
421 list_for_each_entry_safe(dev, next, &tr->devs, list)
424 blk_cleanup_queue(tr->blkcore_priv->rq);
425 unregister_blkdev(tr->major, tr->name);
427 mutex_unlock(&mtd_table_mutex);
429 kfree(tr->blkcore_priv);
431 BUG_ON(!list_empty(&tr->devs));
435 static void __exit mtd_blktrans_exit(void)
437 /* No race here -- if someone's currently in register_mtd_blktrans
438 we're screwed anyway. */
439 if (blktrans_notifier.list.next)
440 unregister_mtd_user(&blktrans_notifier);
443 module_exit(mtd_blktrans_exit);
445 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
446 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
447 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
448 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
450 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
451 MODULE_LICENSE("GPL");
452 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");