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path: root/drivers/md/dm.c
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Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c19
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);