From 052189a2ec956810feefb6a681416c5e6a207646 Mon Sep 17 00:00:00 2001 From: Kiyoshi Ueda Date: Thu, 13 Jan 2011 20:00:00 +0000 Subject: 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 Signed-off-by: Jun'ichi Nomura Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- drivers/md/dm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e504bb40d60e..eaa3af0e0632 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)) -- cgit v1.2.3