2 * $Id: mtd_blkdevs.c,v 1.27 2005/11/07 11:14:20 gleixner Exp $
4 * (C) 2003 David Woodhouse <dwmw2@infradead.org>
6 * Interface to Linux 2.5 block layer for MTD 'translation layers'.
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/module.h>
13 #include <linux/list.h>
15 #include <linux/mtd/blktrans.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/blkdev.h>
18 #include <linux/blkpg.h>
19 #include <linux/spinlock.h>
20 #include <linux/hdreg.h>
21 #include <linux/init.h>
22 #include <linux/mutex.h>
23 #include <linux/kthread.h>
24 #include <asm/uaccess.h>
28 static LIST_HEAD(blktrans_majors);
30 struct mtd_blkcore_priv {
31 struct task_struct *thread;
32 struct request_queue *rq;
33 spinlock_t queue_lock;
36 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
37 struct mtd_blktrans_dev *dev,
40 unsigned long block, nsect;
43 block = req->sector << 9 >> tr->blkshift;
44 nsect = req->current_nr_sectors << 9 >> tr->blkshift;
48 if (!blk_fs_request(req))
51 if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))
54 switch(rq_data_dir(req)) {
56 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
57 if (tr->readsect(dev, block, buf))
65 for (; nsect > 0; nsect--, block++, buf += tr->blksize)
66 if (tr->writesect(dev, block, buf))
71 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
76 static int mtd_blktrans_thread(void *arg)
78 struct mtd_blktrans_ops *tr = arg;
79 struct request_queue *rq = tr->blkcore_priv->rq;
81 /* we might get involved when memory gets low, so use PF_MEMALLOC */
82 current->flags |= PF_MEMALLOC | PF_NOFREEZE;
84 spin_lock_irq(rq->queue_lock);
85 while (!kthread_should_stop()) {
87 struct mtd_blktrans_dev *dev;
90 req = elv_next_request(rq);
93 set_current_state(TASK_INTERRUPTIBLE);
94 spin_unlock_irq(rq->queue_lock);
96 spin_lock_irq(rq->queue_lock);
100 dev = req->rq_disk->private_data;
103 spin_unlock_irq(rq->queue_lock);
105 mutex_lock(&dev->lock);
106 res = do_blktrans_request(tr, dev, req);
107 mutex_unlock(&dev->lock);
109 spin_lock_irq(rq->queue_lock);
111 end_request(req, res);
113 spin_unlock_irq(rq->queue_lock);
118 static void mtd_blktrans_request(struct request_queue *rq)
120 struct mtd_blktrans_ops *tr = rq->queuedata;
121 wake_up_process(tr->blkcore_priv->thread);
125 static int blktrans_open(struct inode *i, struct file *f)
127 struct mtd_blktrans_dev *dev;
128 struct mtd_blktrans_ops *tr;
131 dev = i->i_bdev->bd_disk->private_data;
134 if (!try_module_get(dev->mtd->owner))
137 if (!try_module_get(tr->owner))
140 /* FIXME: Locking. A hot pluggable device can go away
141 (del_mtd_device can be called for it) without its module
143 dev->mtd->usecount++;
146 if (tr->open && (ret = tr->open(dev))) {
147 dev->mtd->usecount--;
148 module_put(dev->mtd->owner);
150 module_put(tr->owner);
156 static int blktrans_release(struct inode *i, struct file *f)
158 struct mtd_blktrans_dev *dev;
159 struct mtd_blktrans_ops *tr;
162 dev = i->i_bdev->bd_disk->private_data;
166 ret = tr->release(dev);
169 dev->mtd->usecount--;
170 module_put(dev->mtd->owner);
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 inode *inode, struct file *file,
187 unsigned int cmd, unsigned long arg)
189 struct mtd_blktrans_dev *dev = inode->i_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 struct block_device_operations mtd_blktrans_ops = {
204 .owner = THIS_MODULE,
205 .open = blktrans_open,
206 .release = blktrans_release,
207 .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 list_head *this;
215 int last_devnum = -1;
218 if (mutex_trylock(&mtd_table_mutex)) {
219 mutex_unlock(&mtd_table_mutex);
223 list_for_each(this, &tr->devs) {
224 struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, 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 mutex_init(&new->lock);
251 list_add_tail(&new->list, &tr->devs);
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;
294 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
296 if (mutex_trylock(&mtd_table_mutex)) {
297 mutex_unlock(&mtd_table_mutex);
301 list_del(&old->list);
303 del_gendisk(old->blkcore_priv);
304 put_disk(old->blkcore_priv);
309 static void blktrans_notify_remove(struct mtd_info *mtd)
311 struct list_head *this, *this2, *next;
313 list_for_each(this, &blktrans_majors) {
314 struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
316 list_for_each_safe(this2, next, &tr->devs) {
317 struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
325 static void blktrans_notify_add(struct mtd_info *mtd)
327 struct list_head *this;
329 if (mtd->type == MTD_ABSENT)
332 list_for_each(this, &blktrans_majors) {
333 struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
335 tr->add_mtd(tr, mtd);
340 static struct mtd_notifier blktrans_notifier = {
341 .add = blktrans_notify_add,
342 .remove = blktrans_notify_remove,
345 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
349 /* Register the notifier if/when the first device type is
350 registered, to prevent the link/init ordering from fucking
352 if (!blktrans_notifier.list.next)
353 register_mtd_user(&blktrans_notifier);
355 tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
356 if (!tr->blkcore_priv)
359 mutex_lock(&mtd_table_mutex);
361 ret = register_blkdev(tr->major, tr->name);
363 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
364 tr->name, tr->major, ret);
365 kfree(tr->blkcore_priv);
366 mutex_unlock(&mtd_table_mutex);
369 spin_lock_init(&tr->blkcore_priv->queue_lock);
371 tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
372 if (!tr->blkcore_priv->rq) {
373 unregister_blkdev(tr->major, tr->name);
374 kfree(tr->blkcore_priv);
375 mutex_unlock(&mtd_table_mutex);
379 tr->blkcore_priv->rq->queuedata = tr;
380 blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
381 tr->blkshift = ffs(tr->blksize) - 1;
383 tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
385 if (IS_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);
390 return PTR_ERR(tr->blkcore_priv->thread);
393 INIT_LIST_HEAD(&tr->devs);
394 list_add(&tr->list, &blktrans_majors);
396 for (i=0; i<MAX_MTD_DEVICES; i++) {
397 if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
398 tr->add_mtd(tr, mtd_table[i]);
401 mutex_unlock(&mtd_table_mutex);
406 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
408 struct list_head *this, *next;
410 mutex_lock(&mtd_table_mutex);
412 /* Clean up the kernel thread */
413 kthread_stop(tr->blkcore_priv->thread);
415 /* Remove it from the list of active majors */
418 list_for_each_safe(this, next, &tr->devs) {
419 struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
423 blk_cleanup_queue(tr->blkcore_priv->rq);
424 unregister_blkdev(tr->major, tr->name);
426 mutex_unlock(&mtd_table_mutex);
428 kfree(tr->blkcore_priv);
430 BUG_ON(!list_empty(&tr->devs));
434 static void __exit mtd_blktrans_exit(void)
436 /* No race here -- if someone's currently in register_mtd_blktrans
437 we're screwed anyway. */
438 if (blktrans_notifier.list.next)
439 unregister_mtd_user(&blktrans_notifier);
442 module_exit(mtd_blktrans_exit);
444 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
445 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
446 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
447 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
449 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
450 MODULE_LICENSE("GPL");
451 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");