From 6ecf23afab13c39d3bb0e2d826d0984b0dd53733 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 5 Mar 2012 13:14:59 -0800 Subject: block: extend queue bypassing to cover blkcg policies Extend queue bypassing such that dying queue is always bypassing and blk-throttle is drained on bypass. With blkcg policies updated to test blk_queue_bypass() instead of blk_queue_dead(), this ensures that no bio or request is held by or going through blkcg policies on a bypassing queue. This will be used to implement blkg cleanup on elevator switches and policy changes. Signed-off-by: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-core.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 98ddef430093..7713c73d9590 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -372,8 +372,7 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) if (q->elevator) elv_drain_elevator(q); - if (drain_all) - blk_throtl_drain(q); + blk_throtl_drain(q); /* * This function might be called on a queue which failed @@ -415,8 +414,8 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) * * In bypass mode, only the dispatch FIFO queue of @q is used. This * function makes @q enter bypass mode and drains all requests which were - * issued before. On return, it's guaranteed that no request has ELVPRIV - * set. + * throttled or issued before. On return, it's guaranteed that no request + * is being throttled or has ELVPRIV set. */ void blk_queue_bypass_start(struct request_queue *q) { @@ -461,6 +460,11 @@ void blk_cleanup_queue(struct request_queue *q) queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q); spin_lock_irq(lock); + + /* dead queue is permanently in bypass mode till released */ + q->bypass_depth++; + queue_flag_set(QUEUE_FLAG_BYPASS, q); + queue_flag_set(QUEUE_FLAG_NOMERGES, q); queue_flag_set(QUEUE_FLAG_NOXMERGES, q); queue_flag_set(QUEUE_FLAG_DEAD, q); -- cgit v1.2.3