diff options
author | Jeff Mahoney <jeffm@suse.com> | 2006-06-26 11:27:22 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-26 20:58:34 +0400 |
commit | f32c10b09940cffc3620ce111315ec44343fd3ca (patch) | |
tree | e5f1ee2febebd9c3b2426973a054ae16b5a80640 /drivers/md | |
parent | 62f75c2f3244553b1290447abd1f1e6b1144d3e9 (diff) | |
download | linux-f32c10b09940cffc3620ce111315ec44343fd3ca.tar.xz |
[PATCH] dm: change minor_lock to spinlock
While removing a device, another another thread might attempt to resurrect it.
This patch replaces the _minor_lock mutex with a spinlock and uses
atomic_dec_and_lock() to serialize reference counting in dm_put().
[akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled]
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/md')
-rw-r--r-- | drivers/md/dm.c | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 6e577e749329..6e65d85d0829 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -26,6 +26,7 @@ static const char *_name = DM_NAME; static unsigned int major = 0; static unsigned int _major = 0; +static DEFINE_SPINLOCK(_minor_lock); /* * One of these is allocated per bio. */ @@ -746,14 +747,13 @@ static int dm_any_congested(void *congested_data, int bdi_bits) /*----------------------------------------------------------------- * An IDR is used to keep track of allocated minor numbers. *---------------------------------------------------------------*/ -static DEFINE_MUTEX(_minor_lock); static DEFINE_IDR(_minor_idr); static void free_minor(unsigned int minor) { - mutex_lock(&_minor_lock); + spin_lock(&_minor_lock); idr_remove(&_minor_idr, minor); - mutex_unlock(&_minor_lock); + spin_unlock(&_minor_lock); } /* @@ -770,7 +770,7 @@ static int specific_minor(struct mapped_device *md, unsigned int minor) if (!r) return -ENOMEM; - mutex_lock(&_minor_lock); + spin_lock(&_minor_lock); if (idr_find(&_minor_idr, minor)) { r = -EBUSY; @@ -788,7 +788,7 @@ static int specific_minor(struct mapped_device *md, unsigned int minor) } out: - mutex_unlock(&_minor_lock); + spin_unlock(&_minor_lock); return r; } @@ -801,7 +801,7 @@ static int next_free_minor(struct mapped_device *md, unsigned int *minor) if (!r) return -ENOMEM; - mutex_lock(&_minor_lock); + spin_lock(&_minor_lock); r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); if (r) { @@ -817,7 +817,7 @@ static int next_free_minor(struct mapped_device *md, unsigned int *minor) *minor = m; out: - mutex_unlock(&_minor_lock); + spin_unlock(&_minor_lock); return r; } @@ -887,9 +887,9 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent) init_waitqueue_head(&md->eventq); /* Populate the mapping, nobody knows we exist yet */ - mutex_lock(&_minor_lock); + spin_lock(&_minor_lock); old_md = idr_replace(&_minor_idr, md, minor); - mutex_unlock(&_minor_lock); + spin_unlock(&_minor_lock); BUG_ON(old_md != MINOR_ALLOCED); @@ -1020,13 +1020,13 @@ static struct mapped_device *dm_find_md(dev_t dev) if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) return NULL; - mutex_lock(&_minor_lock); + spin_lock(&_minor_lock); md = idr_find(&_minor_idr, minor); if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor))) md = NULL; - mutex_unlock(&_minor_lock); + spin_unlock(&_minor_lock); return md; } @@ -1060,11 +1060,10 @@ void dm_put(struct mapped_device *md) { struct dm_table *map; - if (atomic_dec_and_test(&md->holders)) { + if (atomic_dec_and_lock(&md->holders, &_minor_lock)) { map = dm_get_table(md); - mutex_lock(&_minor_lock); idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor); - mutex_unlock(&_minor_lock); + spin_unlock(&_minor_lock); if (!dm_suspended(md)) { dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); |