From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Tue, 21 Oct 2014 11:03:53 +0000 (+0100)
Subject: blockdev: add note that block_job_cb() must be thread-safe
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=723c5d93c51bdb3adbc238ce90195c0864aa6cd5;p=qemu.git

blockdev: add note that block_job_cb() must be thread-safe

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>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1413889440-32577-5-git-send-email-stefanha@redhat.com
---

diff --git a/blockdev.c b/blockdev.c
index 741df9805f..774051b44a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1929,6 +1929,11 @@ 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;