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authorKiyoshi Ueda <k-ueda@ct.jp.nec.com>2011-01-13 20:00:00 +0000
committerAlasdair G Kergon <agk@redhat.com>2011-01-13 20:00:00 +0000
commit052189a2ec956810feefb6a681416c5e6a207646 (patch)
tree52a1fbec2878788c6a2f6565999b97331493bc4c /drivers/md
parentdbc883f1570d992ba926a8c9e22140ba473c6cc1 (diff)
downloadop-kernel-dev-052189a2ec956810feefb6a681416c5e6a207646.zip
op-kernel-dev-052189a2ec956810feefb6a681416c5e6a207646.tar.gz
dm: remove superfluous irq disablement in dm_request_fn
This patch changes spin_lock_irq() to spin_lock() in dm_request_fn(). This patch is just a clean-up and no functional change. The spin_lock_irq() was leftover from the early request-based dm code, where map_request() used to enable interrupts. Since current map_request() never enables interrupts, we can change it to spin_lock() to match the prior spin_unlock(). Auditing through the dm and block-layer code called from map_request(), I confirmed all functions save/restore interrupt status, so no function returning with interrupts enabled. Also I haven't observed any problem on my test environment which uses scsi and lpfc driver after heavy I/O testing with occasional path down/up. Added BUG_ON() to detect breakage in future. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e504bb4..eaa3af0 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1637,13 +1637,15 @@ static void dm_request_fn(struct request_queue *q)
if (map_request(ti, clone, md))
goto requeued;
- spin_lock_irq(q->queue_lock);
+ BUG_ON(!irqs_disabled());
+ spin_lock(q->queue_lock);
}
goto out;
requeued:
- spin_lock_irq(q->queue_lock);
+ BUG_ON(!irqs_disabled());
+ spin_lock(q->queue_lock);
plug_and_out:
if (!elv_queue_empty(q))
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