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dm: disable interrupt when taking map_lock

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This patch disables interrupt when taking map_lock to avoid
lockdep warnings in request-based dm.

request-based dm takes map_lock after taking queue_lock with
disabling interrupt:
  spin_lock_irqsave(queue_lock)
  q->request_fn() == dm_request_fn()
    => dm_get_table()
         => read_lock(map_lock)
while queue_lock could be (but isn't) taken in interrupt context.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Kiyoshi Ueda 2009-06-22 10:12:37 +01:00 committed by Alasdair G Kergon
parent 5d67aa2366
commit 523d9297d4
1 changed files with 9 additions and 6 deletions
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15
drivers/md/dm.c
View file

@ -512,12 +512,13 @@ static void queue_io(struct mapped_device *md, struct bio *bio)
struct dm_table *dm_get_table(struct mapped_device *md)
{
struct dm_table *t;
unsigned long flags;
read_lock(&md->map_lock);
read_lock_irqsave(&md->map_lock, flags);
t = md->map;
if (t)
dm_table_get(t);
read_unlock(&md->map_lock);
read_unlock_irqrestore(&md->map_lock, flags);
return t;
}
@ -1910,6 +1911,7 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
{
struct request_queue *q = md->queue;
sector_t size;
unsigned long flags;
size = dm_table_get_size(t);
@ -1940,10 +1942,10 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
__bind_mempools(md, t);
write_lock(&md->map_lock);
write_lock_irqsave(&md->map_lock, flags);
md->map = t;
dm_table_set_restrictions(t, q, limits);
write_unlock(&md->map_lock);
write_unlock_irqrestore(&md->map_lock, flags);
return 0;
}
@ -1951,14 +1953,15 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
static void __unbind(struct mapped_device *md)
{
struct dm_table *map = md->map;
unsigned long flags;
if (!map)
return;
dm_table_event_callback(map, NULL, NULL);
write_lock(&md->map_lock);
write_lock_irqsave(&md->map_lock, flags);
md->map = NULL;
write_unlock(&md->map_lock);
write_unlock_irqrestore(&md->map_lock, flags);
dm_table_destroy(map);
}