Messages in this thread | | | Date | Fri, 16 May 2014 08:53:22 -0600 | From | Jens Axboe <> | Subject | Re: [PATCH] virtio_blk: fix race between start and stop queue |
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On 2014-05-15 06:33, Ming Lei wrote: > When there isn't enough vring descriptor for adding to vq, > blk-mq will be put as stopped state until some of pending > descriptors are completed & freed. > > Unfortunately, the vq's interrupt may come just before > blk-mq's BLK_MQ_S_STOPPED flag is set, so the blk-mq will > still be kept as stopped even though lots of descriptors > are completed and freed in the interrupt handler. The worst > case is that all pending descriptors are freed in the > interrupt handler, and the queue is kept as stopped forever. > > This patch fixes the problem by starting/stopping blk-mq > with holding vq_lock.
Why not just use blk_mq_start_hw_queues()?
-- Jens Axboe
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