2 * $Id: mtd_blkdevs.c,v 1.25 2005/07/29 01:57:55 tpoynor 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 <asm/semaphore.h>
23 #include <asm/uaccess.h>
25 static LIST_HEAD(blktrans_majors);
27 extern struct semaphore mtd_table_mutex;
28 extern struct mtd_info *mtd_table[];
30 struct mtd_blkcore_priv {
31 struct completion thread_dead;
33 wait_queue_head_t thread_wq;
34 struct request_queue *rq;
35 spinlock_t queue_lock;
38 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
39 struct mtd_blktrans_dev *dev,
42 unsigned long block, nsect;
46 nsect = req->current_nr_sectors;
49 if (!(req->flags & REQ_CMD))
52 if (block + nsect > get_capacity(req->rq_disk))
55 switch(rq_data_dir(req)) {
57 for (; nsect > 0; nsect--, block++, buf += 512)
58 if (tr->readsect(dev, block, buf))
66 for (; nsect > 0; nsect--, block++, buf += 512)
67 if (tr->writesect(dev, block, buf))
72 printk(KERN_NOTICE "Unknown request %ld\n", rq_data_dir(req));
77 static int mtd_blktrans_thread(void *arg)
79 struct mtd_blktrans_ops *tr = arg;
80 struct request_queue *rq = tr->blkcore_priv->rq;
82 /* we might get involved when memory gets low, so use PF_MEMALLOC */
83 current->flags |= PF_MEMALLOC | PF_NOFREEZE;
85 daemonize("%sd", tr->name);
87 /* daemonize() doesn't do this for us since some kernel threads
88 actually want to deal with signals. We can't just call
89 exit_sighand() since that'll cause an oops when we finally
91 spin_lock_irq(¤t->sighand->siglock);
92 sigfillset(¤t->blocked);
94 spin_unlock_irq(¤t->sighand->siglock);
96 spin_lock_irq(rq->queue_lock);
98 while (!tr->blkcore_priv->exiting) {
100 struct mtd_blktrans_dev *dev;
102 DECLARE_WAITQUEUE(wait, current);
104 req = elv_next_request(rq);
107 add_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
108 set_current_state(TASK_INTERRUPTIBLE);
110 spin_unlock_irq(rq->queue_lock);
113 remove_wait_queue(&tr->blkcore_priv->thread_wq, &wait);
115 spin_lock_irq(rq->queue_lock);
120 dev = req->rq_disk->private_data;
123 spin_unlock_irq(rq->queue_lock);
126 res = do_blktrans_request(tr, dev, req);
129 spin_lock_irq(rq->queue_lock);
131 end_request(req, res);
133 spin_unlock_irq(rq->queue_lock);
135 complete_and_exit(&tr->blkcore_priv->thread_dead, 0);
138 static void mtd_blktrans_request(struct request_queue *rq)
140 struct mtd_blktrans_ops *tr = rq->queuedata;
141 wake_up(&tr->blkcore_priv->thread_wq);
145 static int blktrans_open(struct inode *i, struct file *f)
147 struct mtd_blktrans_dev *dev;
148 struct mtd_blktrans_ops *tr;
151 dev = i->i_bdev->bd_disk->private_data;
154 if (!try_module_get(dev->mtd->owner))
157 if (!try_module_get(tr->owner))
160 /* FIXME: Locking. A hot pluggable device can go away
161 (del_mtd_device can be called for it) without its module
163 dev->mtd->usecount++;
166 if (tr->open && (ret = tr->open(dev))) {
167 dev->mtd->usecount--;
168 module_put(dev->mtd->owner);
170 module_put(tr->owner);
176 static int blktrans_release(struct inode *i, struct file *f)
178 struct mtd_blktrans_dev *dev;
179 struct mtd_blktrans_ops *tr;
182 dev = i->i_bdev->bd_disk->private_data;
186 ret = tr->release(dev);
189 dev->mtd->usecount--;
190 module_put(dev->mtd->owner);
191 module_put(tr->owner);
198 static int blktrans_ioctl(struct inode *inode, struct file *file,
199 unsigned int cmd, unsigned long arg)
201 struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
202 struct mtd_blktrans_ops *tr = dev->tr;
207 return tr->flush(dev);
208 /* The core code did the work, we had nothing to do. */
213 struct hd_geometry g;
216 memset(&g, 0, sizeof(g));
217 ret = tr->getgeo(dev, &g);
221 g.start = get_start_sect(inode->i_bdev);
222 if (copy_to_user((void __user *)arg, &g, sizeof(g)))
231 struct block_device_operations mtd_blktrans_ops = {
232 .owner = THIS_MODULE,
233 .open = blktrans_open,
234 .release = blktrans_release,
235 .ioctl = blktrans_ioctl,
238 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
240 struct mtd_blktrans_ops *tr = new->tr;
241 struct list_head *this;
242 int last_devnum = -1;
245 if (!down_trylock(&mtd_table_mutex)) {
246 up(&mtd_table_mutex);
250 list_for_each(this, &tr->devs) {
251 struct mtd_blktrans_dev *d = list_entry(this, struct mtd_blktrans_dev, list);
252 if (new->devnum == -1) {
253 /* Use first free number */
254 if (d->devnum != last_devnum+1) {
255 /* Found a free devnum. Plug it in here */
256 new->devnum = last_devnum+1;
257 list_add_tail(&new->list, &d->list);
260 } else if (d->devnum == new->devnum) {
261 /* Required number taken */
263 } else if (d->devnum > new->devnum) {
264 /* Required number was free */
265 list_add_tail(&new->list, &d->list);
268 last_devnum = d->devnum;
270 if (new->devnum == -1)
271 new->devnum = last_devnum+1;
273 if ((new->devnum << tr->part_bits) > 256) {
277 init_MUTEX(&new->sem);
278 list_add_tail(&new->list, &tr->devs);
283 gd = alloc_disk(1 << tr->part_bits);
285 list_del(&new->list);
288 gd->major = tr->major;
289 gd->first_minor = (new->devnum) << tr->part_bits;
290 gd->fops = &mtd_blktrans_ops;
292 snprintf(gd->disk_name, sizeof(gd->disk_name),
293 "%s%c", tr->name, (tr->part_bits?'a':'0') + new->devnum);
295 /* 2.5 has capacity in units of 512 bytes while still
296 having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
297 set_capacity(gd, (new->size * new->blksize) >> 9);
299 gd->private_data = new;
300 new->blkcore_priv = gd;
301 gd->queue = tr->blkcore_priv->rq;
311 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
313 if (!down_trylock(&mtd_table_mutex)) {
314 up(&mtd_table_mutex);
318 list_del(&old->list);
320 del_gendisk(old->blkcore_priv);
321 put_disk(old->blkcore_priv);
326 static void blktrans_notify_remove(struct mtd_info *mtd)
328 struct list_head *this, *this2, *next;
330 list_for_each(this, &blktrans_majors) {
331 struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
333 list_for_each_safe(this2, next, &tr->devs) {
334 struct mtd_blktrans_dev *dev = list_entry(this2, struct mtd_blktrans_dev, list);
342 static void blktrans_notify_add(struct mtd_info *mtd)
344 struct list_head *this;
346 if (mtd->type == MTD_ABSENT)
349 list_for_each(this, &blktrans_majors) {
350 struct mtd_blktrans_ops *tr = list_entry(this, struct mtd_blktrans_ops, list);
352 tr->add_mtd(tr, mtd);
357 static struct mtd_notifier blktrans_notifier = {
358 .add = blktrans_notify_add,
359 .remove = blktrans_notify_remove,
362 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
366 /* Register the notifier if/when the first device type is
367 registered, to prevent the link/init ordering from fucking
369 if (!blktrans_notifier.list.next)
370 register_mtd_user(&blktrans_notifier);
372 tr->blkcore_priv = kmalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
373 if (!tr->blkcore_priv)
376 memset(tr->blkcore_priv, 0, sizeof(*tr->blkcore_priv));
378 down(&mtd_table_mutex);
380 ret = register_blkdev(tr->major, tr->name);
382 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
383 tr->name, tr->major, ret);
384 kfree(tr->blkcore_priv);
385 up(&mtd_table_mutex);
388 spin_lock_init(&tr->blkcore_priv->queue_lock);
389 init_completion(&tr->blkcore_priv->thread_dead);
390 init_waitqueue_head(&tr->blkcore_priv->thread_wq);
392 tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
393 if (!tr->blkcore_priv->rq) {
394 unregister_blkdev(tr->major, tr->name);
395 kfree(tr->blkcore_priv);
396 up(&mtd_table_mutex);
400 tr->blkcore_priv->rq->queuedata = tr;
402 ret = kernel_thread(mtd_blktrans_thread, tr, CLONE_KERNEL);
404 blk_cleanup_queue(tr->blkcore_priv->rq);
405 unregister_blkdev(tr->major, tr->name);
406 kfree(tr->blkcore_priv);
407 up(&mtd_table_mutex);
411 INIT_LIST_HEAD(&tr->devs);
412 list_add(&tr->list, &blktrans_majors);
414 for (i=0; i<MAX_MTD_DEVICES; i++) {
415 if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
416 tr->add_mtd(tr, mtd_table[i]);
419 up(&mtd_table_mutex);
424 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
426 struct list_head *this, *next;
428 down(&mtd_table_mutex);
430 /* Clean up the kernel thread */
431 tr->blkcore_priv->exiting = 1;
432 wake_up(&tr->blkcore_priv->thread_wq);
433 wait_for_completion(&tr->blkcore_priv->thread_dead);
435 /* Remove it from the list of active majors */
438 list_for_each_safe(this, next, &tr->devs) {
439 struct mtd_blktrans_dev *dev = list_entry(this, struct mtd_blktrans_dev, list);
443 blk_cleanup_queue(tr->blkcore_priv->rq);
444 unregister_blkdev(tr->major, tr->name);
446 up(&mtd_table_mutex);
448 kfree(tr->blkcore_priv);
450 if (!list_empty(&tr->devs))
455 static void __exit mtd_blktrans_exit(void)
457 /* No race here -- if someone's currently in register_mtd_blktrans
458 we're screwed anyway. */
459 if (blktrans_notifier.list.next)
460 unregister_mtd_user(&blktrans_notifier);
463 module_exit(mtd_blktrans_exit);
465 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
466 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
467 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
468 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
470 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
471 MODULE_LICENSE("GPL");
472 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");