| From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
| From: Alistair Delva <adelva@google.com> |
| Date: Fri, 15 Nov 2019 15:38:06 -0800 |
| Subject: ANDROID: virtio_blk: Remove BUG_ON for discard/zero ops |
| |
| The virtio_blk driver used by cuttlefish can crash if discard/zero ops, |
| added in 4.20, pass through virtio_queue_rq(). Our theory is that this |
| happens because multiple discards are merged, causing nr_phys_segments |
| to be increased beyond the sg_elem size. This makes sense as a |
| discard/zero is a form of I/O not backed by specific data. |
| |
| This patch should be submitted upstream once the true root cause has |
| been tracked down and full analysis of the issue has been done. |
| |
| Originally-by: Satya Tangirala <satyat@google.com> |
| Bug: 144592287 |
| Test: boot cuttlefish with f2fs userdata and wait 1 minute |
| Change-Id: Ic73e08035c91ec9c718e6496930b326d084062a4 |
| Signed-off-by: Alistair Delva <adelva@google.com> |
| --- |
| drivers/block/virtio_blk.c | 6 ++++-- |
| 1 file changed, 4 insertions(+), 2 deletions(-) |
| |
| diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c |
| index 7ffd719d89de..f817bc651ed3 100644 |
| --- a/drivers/block/virtio_blk.c |
| +++ b/drivers/block/virtio_blk.c |
| @@ -282,8 +282,6 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, |
| bool unmap = false; |
| u32 type; |
| |
| - BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); |
| - |
| switch (req_op(req)) { |
| case REQ_OP_READ: |
| case REQ_OP_WRITE: |
| @@ -311,6 +309,10 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, |
| return BLK_STS_IOERR; |
| } |
| |
| + BUG_ON(type != VIRTIO_BLK_T_DISCARD && |
| + type != VIRTIO_BLK_T_WRITE_ZEROES && |
| + (req->nr_phys_segments + 2 > vblk->sg_elems)); |
| + |
| vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type); |
| vbr->out_hdr.sector = type ? |
| 0 : cpu_to_virtio64(vblk->vdev, blk_rq_pos(req)); |
