diff options
| -rw-r--r-- | drivers/md/dm.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 4d710b7a133..87d8ca1121e 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -54,6 +54,8 @@ union map_info *dm_get_mapinfo(struct bio *bio) return NULL; } +#define MINOR_ALLOCED ((void *)-1) + /* * Bits for the md->flags field. */ @@ -777,7 +779,7 @@ static int specific_minor(struct mapped_device *md, unsigned int minor) goto out; } - r = idr_get_new_above(&_minor_idr, md, minor, &m); + r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); if (r) { goto out; } @@ -806,7 +808,7 @@ static int next_free_minor(struct mapped_device *md, unsigned int *minor) goto out; } - r = idr_get_new(&_minor_idr, md, &m); + r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); if (r) { goto out; } @@ -833,6 +835,7 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent) { int r; struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL); + void *old_md; if (!md) { DMWARN("unable to allocate device, out of memory."); @@ -888,6 +891,13 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent) init_waitqueue_head(&md->wait); init_waitqueue_head(&md->eventq); + /* Populate the mapping, nobody knows we exist yet */ + mutex_lock(&_minor_lock); + old_md = idr_replace(&_minor_idr, md, minor); + mutex_unlock(&_minor_lock); + + BUG_ON(old_md != MINOR_ALLOCED); + return md; bad4: @@ -1018,7 +1028,7 @@ static struct mapped_device *dm_find_md(dev_t dev) mutex_lock(&_minor_lock); md = idr_find(&_minor_idr, minor); - if (!md || (dm_disk(md)->first_minor != minor)) + if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor))) md = NULL; mutex_unlock(&_minor_lock); @@ -1057,6 +1067,9 @@ void dm_put(struct mapped_device *md) if (atomic_dec_and_test(&md->holders)) { map = dm_get_table(md); + mutex_lock(&_minor_lock); + idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor); + mutex_unlock(&_minor_lock); if (!dm_suspended(md)) { dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); |