[Qemu-devel] [PATCH] virtio-9p: use accessor to get thread_pool

[Qemu-devel] [PATCH] virtio-9p: use accessor to get thread_pool

[Greg Kurz]

The aio_context_new() function does not allocate a thread pool. This is
deferred to the first call to the aio_get_thread_pool() accessor. It is
hence forbidden to access the thread_pool field directly, as it may be
NULL. The accessor *must* be used always.

Fixes: ebac1202c95a4f1b76b6ef3f0f63926fa76e753e
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---

Michael,

I did not have time to reproduce the issue, and therefore to
effectively test this patch fixes it. Maybe you can do it ?

Thanks.

--
Greg

 hw/9pfs/virtio-9p-coth.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/9pfs/virtio-9p-coth.c b/hw/9pfs/virtio-9p-coth.c
index fb6e8f80e0f4..ab9425c60fd2 100644
--- a/hw/9pfs/virtio-9p-coth.c
+++ b/hw/9pfs/virtio-9p-coth.c
@@ -36,6 +36,6 @@ static int coroutine_enter_func(void *arg)
 void co_run_in_worker_bh(void *opaque)
 {
     Coroutine *co = opaque;
-    thread_pool_submit_aio(qemu_get_aio_context()->thread_pool,
+    thread_pool_submit_aio(aio_get_thread_pool(qemu_get_aio_context()),
                            coroutine_enter_func, co, coroutine_enter_cb, co);
 }

Re: [Qemu-devel] [PATCH] virtio-9p: use accessor to get thread_pool

[Michael Tokarev]

20.12.2015 14:19, Greg Kurz wrote:
> The aio_context_new() function does not allocate a thread pool. This is
> deferred to the first call to the aio_get_thread_pool() accessor. It is
> hence forbidden to access the thread_pool field directly, as it may be
> NULL. The accessor *must* be used always.
> 
> Fixes: ebac1202c95a4f1b76b6ef3f0f63926fa76e753e
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
Cc: qemu-stable@nongnu.org

> Michael,
> 
> I did not have time to reproduce the issue, and therefore to
> effectively test this patch fixes it. Maybe you can do it ?

Yes, it effectively fixes the issue.

Meanwhile I looked at the whole thing with how thread pools are
allocated, and now can add my R-b too.

Thank you!

/mjt