ide: Requeue request after DMA timeout (6072f749) · Commits · 戴 / test

I noticed that my KVM virtual machines were experiencing IDE issues resulting in processes stuck on waiting for buffers to complete. The root cause is of course race conditions in the ancient qemu backend that I'm using. However, the fact that the guest isn't recovering is a bug. I've tracked it down to the change made last year to dequeue requests at the start rather than at the end in the IDE layer. commit Author: Tejun Heo <tj@kernel.org> Date: Fri May 8 11:53:59 2009 +0900 ide: dequeue in-flight request The problem is that the function ide_dma_timeout_retry does not requeue the current request, causing one request to be lost for each DMA timeout. This patch fixes this by requeueing the request. Signed-off-by:

Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/ide/ide-dma.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -492,6 +492,7 @@ ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
		if (rq) {
		hwif->rq = NULL;
		rq->errors = 0;
		ide_requeue_and_plug(drive, rq);
		}
		return ret;
		}

drivers/ide/ide-io.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -566,7 +566,7 @@ plug_device_2:
		blk_plug_device(q);
		}

		static void ide_requeue_and_plug(ide_drive_t drive, struct request rq)
		void ide_requeue_and_plug(ide_drive_t drive, struct request rq)
		{
		struct request_queue *q = drive->queue;
		unsigned long flags;

include/linux/ide.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1169,6 +1169,7 @@ extern void ide_stall_queue(ide_drive_t *drive, unsigned long timeout);
		extern void ide_timer_expiry(unsigned long);
		extern irqreturn_t ide_intr(int irq, void *dev_id);
		extern void do_ide_request(struct request_queue *);
		extern void ide_requeue_and_plug(ide_drive_t drive, struct request rq);

		void ide_init_disk(struct gendisk , ide_drive_t );

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