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

[Stefan Hajnoczi]

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 <address@hidden>
---
 blockdev.c | 5 +++++
 1 file changed, 5 insertions(+)

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;
 
-- 
1.9.3