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Commit 523d9297 authored by Kiyoshi Ueda's avatar Kiyoshi Ueda Committed by Alasdair G Kergon
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dm: disable interrupt when taking map_lock 



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: default avatarKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: default avatarChristof Schmitt <christof.schmitt@de.ibm.com>
Acked-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 5d67aa23

drivers/md/dm.c

+9 −6
Original line number Diff line number Diff line
@@ -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);

}