3.14-stable patches

added patches:
	virtio_blk-fix-race-between-start-and-stop-queue.patch

diff --git a/queue-3.14/series b/queue-3.14/series
index e1b652bea8cb2488e706cc5480f1fdbc4a44b76e..6fd10e9e29b63af1e2260da09b09dd24f709996b 100644 (file)
--- a/queue-3.14/series
+++ b/queue-3.14/series
@@ -28,3 +28,4 @@ mips-fix-typo-when-reporting-cache-and-ftlb-errors-for-imgtec-cores.patch
 dm-thin-add-no_space_timeout-dm-thin-pool-module-param.patch
 dm-cache-always-split-discards-on-cache-block-boundaries.patch
 revert-revert-mm-vmscan-do-not-swap-anon-pages-just.patch
+virtio_blk-fix-race-between-start-and-stop-queue.patch

diff --git a/queue-3.14/virtio_blk-fix-race-between-start-and-stop-queue.patch b/queue-3.14/virtio_blk-fix-race-between-start-and-stop-queue.patch
new file mode 100644 (file)
index 0000000..3815003
--- /dev/null
+++ b/queue-3.14/virtio_blk-fix-race-between-start-and-stop-queue.patch
@@ -0,0 +1,59 @@
+From aa0818c6ee8d8e4772725a43550823347bc1ad30 Mon Sep 17 00:00:00 2001
+From: Ming Lei <tom.leiming@gmail.com>
+Date: Fri, 16 May 2014 23:31:21 +0800
+Subject: virtio_blk: fix race between start and stop queue
+
+From: Ming Lei <tom.leiming@gmail.com>
+
+commit aa0818c6ee8d8e4772725a43550823347bc1ad30 upstream.
+
+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.
+
+Cc: Jens Axboe <axboe@kernel.dk>
+Cc: Rusty Russell <rusty@rustcorp.com.au>
+Signed-off-by: Ming Lei <tom.leiming@gmail.com>
+Signed-off-by: Jens Axboe <axboe@fb.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+
+---
+ drivers/block/virtio_blk.c |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/block/virtio_blk.c
++++ b/drivers/block/virtio_blk.c
+@@ -144,11 +144,11 @@ static void virtblk_done(struct virtqueu
+               if (unlikely(virtqueue_is_broken(vq)))
+                       break;
+       } while (!virtqueue_enable_cb(vq));
+-      spin_unlock_irqrestore(&vblk->vq_lock, flags);
+ 
+       /* In case queue is stopped waiting for more buffers. */
+       if (req_done)
+               blk_mq_start_stopped_hw_queues(vblk->disk->queue);
++      spin_unlock_irqrestore(&vblk->vq_lock, flags);
+ }
+ 
+ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
+@@ -200,8 +200,8 @@ static int virtio_queue_rq(struct blk_mq
+       spin_lock_irqsave(&vblk->vq_lock, flags);
+       if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) {
+               virtqueue_kick(vblk->vq);
+-              spin_unlock_irqrestore(&vblk->vq_lock, flags);
+               blk_mq_stop_hw_queue(hctx);
++              spin_unlock_irqrestore(&vblk->vq_lock, flags);
+               return BLK_MQ_RQ_QUEUE_BUSY;
+       }
+