Fam,
On 07/29/16 12:22, Fam Zheng wrote:
> At system_reset, there is no point in retrying the queued request,
> because the driver that issued the request won't be around any more.
>
> Analyzed-by: Laszlo Ersek <[email protected]>
> Reported-by: Laszlo Ersek <[email protected]>
> Signed-off-by: Fam Zheng <[email protected]>
> ---
> hw/block/virtio-blk.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 475a822..89eca65 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -654,6 +654,7 @@ static void virtio_blk_reset(VirtIODevice *vdev)
> {
> VirtIOBlock *s = VIRTIO_BLK(vdev);
> AioContext *ctx;
> + VirtIOBlockReq *req;
>
> /*
> * This should cancel pending requests, but can't do nicely until there
> @@ -661,6 +662,11 @@ static void virtio_blk_reset(VirtIODevice *vdev)
> */
> ctx = blk_get_aio_context(s->blk);
> aio_context_acquire(ctx);
> + while (s->rq) {
> + req = s->rq;
> + s->rq = req->next;
> + virtio_blk_free_request(req);
> + }
> blk_drain(s->blk);
>
> if (s->dataplane) {
>
The comment
/*
* This should cancel pending requests, but can't do nicely until there
* are per-device request lists.
*/
dates back to
commit 6e02c38dadfe4cf02b0da6135adfd8d9352b90e1
Author: aliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Date: Thu Dec 4 19:52:44 2008 +0000
Add virtio-blk support
Virtio-blk is a paravirtual block device based on VirtIO. It can be used by
specifying the if=virtio parameter to the -drive parameter.
When using -enable-kvm, it can achieve very good performance compared to
IDE or
SCSI.
Signed-off-by: Anthony Liguori <[email protected]>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5870
c046a42c-6fe2-441c-8c8c-71466251a162
I think the comment is obsolete now, the idea that it expresses was actually
fixed in the following commit, in my opinion:
commit 6e40b3bfc7e82823cf4df5f0bf668f56db41e53a
Author: Alexander Yarygin <[email protected]>
Date: Wed Jun 17 13:37:20 2015 +0300
virtio-blk: Use blk_drain() to drain IO requests
Each call of the virtio_blk_reset() function calls blk_drain_all(),
which works for all existing BlockDriverStates, while draining only
one is needed.
This patch replaces blk_drain_all() by blk_drain() in
virtio_blk_reset(). virtio_blk_data_plane_stop() should be called
after draining because it restores vblk->complete_request.
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Cornelia Huck <[email protected]>
Cc: Kevin Wolf <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Stefan Hajnoczi <[email protected]>
Signed-off-by: Alexander Yarygin <[email protected]>
Message-id: [email protected]
Signed-off-by: Stefan Hajnoczi <[email protected]>
So how about turning this patch into a two part series: the first patch should
drop the comment, and reference 6e40b3bfc7e82823cf4df5f0bf668f56db41e53a, while
the second patch should be this patch?
For this patch:
Reviewed-by: Laszlo Ersek <[email protected]>
I definitely recommend that Stefan review this patch too.
Thanks!
Laszlo
