diff mbox

[04/11] blockdev: add note that block_job_cb() must be thread-safe

Message ID 1412182919-9550-5-git-send-email-stefanha@redhat.com
State New
Headers show

Commit Message

Stefan Hajnoczi Oct. 1, 2014, 5:01 p.m. UTC 
This function is correct but we should document the constraint that
everything must be thread-safe.

Emitting QMP events and scheduling BHs are both thread-safe so nothing
needs to be done here.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 blockdev.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Max Reitz Oct. 1, 2014, 6:42 p.m. UTC | #1 
On 01.10.2014 19:01, Stefan Hajnoczi wrote:
> This function is correct but we should document the constraint that
> everything must be thread-safe.
>
> Emitting QMP events and scheduling BHs are both thread-safe so nothing
> needs to be done here.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>   blockdev.c | 5 +++++
>   1 file changed, 5 insertions(+)

Reviewed-by: Max Reitz <mreitz@redhat.com>
diff mbox

Patch

diff --git a/blockdev.c b/blockdev.c
index 5e38f34..1c79352 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1889,6 +1889,11 @@  out:
 
 static void block_job_cb(void *opaque, int ret)
 {
+    /* Note that this function may be executed from another AioContext besides
+     * the QEMU main loop.  If you need to access anything that assumes the
+     * QEMU global mutex, use a BH or introduce a mutex.
+     */
+
     BlockDriverState *bs = opaque;
     const char *msg = NULL;