From 5261b85e586afe6ebe54e16e0a8acc32fc6d4902 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 13 Mar 2014 11:23:39 +1030 Subject: [PATCH] virtio_blk: don't crash, report error if virtqueue is broken. A bad implementation of virtio might cause us to mark the virtqueue broken: we'll dev_err() in that case, and the device is useless, but let's not BUG_ON(). ENOMEM or ENOSPC implies the ring is full, and we should try again later (-ENOMEM is documented to happen, but doesn't, as we fall through to ENOSPC). EIO means it's broken. Signed-off-by: Rusty Russell --- drivers/block/virtio_blk.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index b1cb3f4c4db4..a2db9ed288f2 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -158,6 +158,7 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req) unsigned long flags; unsigned int num; const bool last = (req->cmd_flags & REQ_END) != 0; + int err; BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); @@ -198,11 +199,16 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req) } spin_lock_irqsave(&vblk->vq_lock, flags); - if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) { + err = __virtblk_add_req(vblk->vq, vbr, vbr->sg, num); + if (err) { virtqueue_kick(vblk->vq); spin_unlock_irqrestore(&vblk->vq_lock, flags); blk_mq_stop_hw_queue(hctx); - return BLK_MQ_RQ_QUEUE_BUSY; + /* Out of mem doesn't actually happen, since we fall back + * to direct descriptors */ + if (err == -ENOMEM || err == -ENOSPC) + return BLK_MQ_RQ_QUEUE_BUSY; + return BLK_MQ_RQ_QUEUE_ERROR; } if (last) -- 2.39.5