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Koen Kooi
df83a59b6b
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
104 lines
3.4 KiB
Diff
104 lines
3.4 KiB
Diff
From b0b5f9284f3f86ce8c28aa112d267d261a5201e9 Mon Sep 17 00:00:00 2001
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From: Asias He <asias@redhat.com>
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Date: Fri, 25 May 2012 16:03:27 +0800
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Subject: [PATCH 38/70] virtio-blk: Use block layer provided spinlock
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commit 2c95a3290919541b846bee3e0fbaa75860929f53 upstream.
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Block layer will allocate a spinlock for the queue if the driver does
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not provide one in blk_init_queue().
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The reason to use the internal spinlock is that blk_cleanup_queue() will
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switch to use the internal spinlock in the cleanup code path.
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if (q->queue_lock != &q->__queue_lock)
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q->queue_lock = &q->__queue_lock;
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However, processes which are in D state might have taken the driver
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provided spinlock, when the processes wake up, they would release the
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block provided spinlock.
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=====================================
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[ BUG: bad unlock balance detected! ]
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3.4.0-rc7+ #238 Not tainted
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-------------------------------------
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fio/3587 is trying to release lock (&(&q->__queue_lock)->rlock) at:
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[<ffffffff813274d2>] blk_queue_bio+0x2a2/0x380
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but there are no more locks to release!
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other info that might help us debug this:
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1 lock held by fio/3587:
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#0: (&(&vblk->lock)->rlock){......}, at:
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[<ffffffff8132661a>] get_request_wait+0x19a/0x250
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Other drivers use block layer provided spinlock as well, e.g. SCSI.
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Switching to the block layer provided spinlock saves a bit of memory and
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does not increase lock contention. Performance test shows no real
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difference is observed before and after this patch.
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Changes in v2: Improve commit log as Michael suggested.
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Cc: virtualization@lists.linux-foundation.org
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Cc: kvm@vger.kernel.org
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Signed-off-by: Asias He <asias@redhat.com>
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Acked-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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[bwh: Backported to 3.2: adjust context]
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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drivers/block/virtio_blk.c | 9 +++------
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1 files changed, 3 insertions(+), 6 deletions(-)
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diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
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index e46f2f7..650a308 100644
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--- a/drivers/block/virtio_blk.c
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+++ b/drivers/block/virtio_blk.c
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@@ -20,8 +20,6 @@ struct workqueue_struct *virtblk_wq;
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struct virtio_blk
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{
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- spinlock_t lock;
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-
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struct virtio_device *vdev;
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struct virtqueue *vq;
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@@ -62,7 +60,7 @@ static void blk_done(struct virtqueue *vq)
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unsigned int len;
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unsigned long flags;
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- spin_lock_irqsave(&vblk->lock, flags);
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+ spin_lock_irqsave(vblk->disk->queue->queue_lock, flags);
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while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
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int error;
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@@ -97,7 +95,7 @@ static void blk_done(struct virtqueue *vq)
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}
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/* In case queue is stopped waiting for more buffers. */
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blk_start_queue(vblk->disk->queue);
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- spin_unlock_irqrestore(&vblk->lock, flags);
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+ spin_unlock_irqrestore(vblk->disk->queue->queue_lock, flags);
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}
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static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
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@@ -384,7 +382,6 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
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}
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INIT_LIST_HEAD(&vblk->reqs);
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- spin_lock_init(&vblk->lock);
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vblk->vdev = vdev;
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vblk->sg_elems = sg_elems;
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sg_init_table(vblk->sg, vblk->sg_elems);
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@@ -410,7 +407,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
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goto out_mempool;
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}
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- q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
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+ q = vblk->disk->queue = blk_init_queue(do_virtblk_request, NULL);
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if (!q) {
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err = -ENOMEM;
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goto out_put_disk;
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--
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1.7.7.6
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