[PULL for-6.1 0/3] Block patches

[PULL for-6.1 0/3] Block patches

[Stefan Hajnoczi]

The following changes since commit 3521ade3510eb5cefb2e27a101667f25dad89935:

  Merge remote-tracking branch 'remotes/thuth-gitlab/tags/pull-request-2021-07-29' into staging (2021-07-29 13:17:20 +0100)

are available in the Git repository at:

  https://gitlab.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to cc8eecd7f105a1dff5876adeb238a14696061a4a:

  MAINTAINERS: Added myself as a reviewer for the NVMe Block Driver (2021-07-29 17:17:34 +0100)

----------------------------------------------------------------
Pull request

The main fix here is for io_uring. Spurious -EAGAIN errors can happen and the
request needs to be resubmitted.

The MAINTAINERS changes carry no risk and we might as well include them in QEMU
6.1.

----------------------------------------------------------------

Fabian Ebner (1):
  block/io_uring: resubmit when result is -EAGAIN

Philippe Mathieu-Daudé (1):
  MAINTAINERS: Added myself as a reviewer for the NVMe Block Driver

Stefano Garzarella (1):
  MAINTAINERS: add Stefano Garzarella as io_uring reviewer

 MAINTAINERS      |  2 ++
 block/io_uring.c | 16 +++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

-- 
2.31.1

[PULL for-6.1 1/3] MAINTAINERS: add Stefano Garzarella as io_uring reviewer

[Stefan Hajnoczi]

From: Stefano Garzarella <sgarzare@redhat.com>

I've been working with io_uring for a while so I'd like to help
with reviews.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20210728131515.131045-1-sgarzare@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 42ac45c3e5..1776d0950b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3257,6 +3257,7 @@ Linux io_uring
 M: Aarushi Mehta <mehta.aaru20@gmail.com>
 M: Julia Suvorova <jusual@redhat.com>
 M: Stefan Hajnoczi <stefanha@redhat.com>
+R: Stefano Garzarella <sgarzare@redhat.com>
 L: qemu-block@nongnu.org
 S: Maintained
 F: block/io_uring.c
-- 
2.31.1

[PULL for-6.1 2/3] block/io_uring: resubmit when result is -EAGAIN

[Stefan Hajnoczi]

From: Fabian Ebner <f.ebner@proxmox.com>

Linux SCSI can throw spurious -EAGAIN in some corner cases in its
completion path, which will end up being the result in the completed
io_uring request.

Resubmitting such requests should allow block jobs to complete, even
if such spurious errors are encountered.

Co-authored-by: Stefan Hajnoczi <stefanha@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
Message-id: 20210729091029.65369-1-f.ebner@proxmox.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/io_uring.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/block/io_uring.c b/block/io_uring.c
index 00a3ee9fb8..dfa475cc87 100644
--- a/block/io_uring.c
+++ b/block/io_uring.c
@@ -165,7 +165,21 @@ static void luring_process_completions(LuringState *s)
         total_bytes = ret + luringcb->total_read;
 
         if (ret < 0) {
-            if (ret == -EINTR) {
+            /*
+             * Only writev/readv/fsync requests on regular files or host block
+             * devices are submitted. Therefore -EAGAIN is not expected but it's
+             * known to happen sometimes with Linux SCSI. Submit again and hope
+             * the request completes successfully.
+             *
+             * For more information, see:
+             * https://lore.kernel.org/io-uring/20210727165811.284510-3-axboe@kernel.dk/T/#u
+             *
+             * If the code is changed to submit other types of requests in the
+             * future, then this workaround may need to be extended to deal with
+             * genuine -EAGAIN results that should not be resubmitted
+             * immediately.
+             */
+            if (ret == -EINTR || ret == -EAGAIN) {
                 luring_resubmit(s, luringcb);
                 continue;
             }
-- 
2.31.1

[PULL for-6.1 3/3] MAINTAINERS: Added myself as a reviewer for the NVMe Block Driver

[Stefan Hajnoczi]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

I'm interested in following the activity around the NVMe bdrv.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210728183340.2018313-1-philmd@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 1776d0950b..a3d598459a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3178,6 +3178,7 @@ F: block/null.c
 NVMe Block Driver
 M: Stefan Hajnoczi <stefanha@redhat.com>
 R: Fam Zheng <fam@euphon.net>
+R: Philippe Mathieu-Daudé <philmd@redhat.com>
 L: qemu-block@nongnu.org
 S: Supported
 F: block/nvme*
-- 
2.31.1

Re: [PULL for-6.1 0/3] Block patches

[Peter Maydell]

On Thu, 29 Jul 2021 at 17:23, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> The following changes since commit 3521ade3510eb5cefb2e27a101667f25dad89935:
>
>   Merge remote-tracking branch 'remotes/thuth-gitlab/tags/pull-request-2021-07-29' into staging (2021-07-29 13:17:20 +0100)
>
> are available in the Git repository at:
>
>   https://gitlab.com/stefanha/qemu.git tags/block-pull-request
>
> for you to fetch changes up to cc8eecd7f105a1dff5876adeb238a14696061a4a:
>
>   MAINTAINERS: Added myself as a reviewer for the NVMe Block Driver (2021-07-29 17:17:34 +0100)
>
> ----------------------------------------------------------------
> Pull request
>
> The main fix here is for io_uring. Spurious -EAGAIN errors can happen and the
> request needs to be resubmitted.
>
> The MAINTAINERS changes carry no risk and we might as well include them in QEMU
> 6.1.


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/6.1
for any user-visible changes.

-- PMM