[PATCH 3/7] block/nbd: assert attach/detach runs in the proper context

[Roman Kagan]

Document (via a comment and an assert) that
nbd_client_detach_aio_context and nbd_client_attach_aio_context_bh run
in the desired aio_context.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
---
 block/nbd.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/block/nbd.c b/block/nbd.c
index 1d8edb5b21..658b827d24 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -241,6 +241,12 @@ static void nbd_client_detach_aio_context(BlockDriverState 
*bs)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
 
+    /*
+     * This runs in the (old, about to be detached) aio context of the @bs so
+     * accessing the stuff on @s is concurrency-free.
+     */
+    assert(qemu_get_current_aio_context() == bdrv_get_aio_context(bs));
+
     /* Timer is deleted in nbd_client_co_drain_begin() */
     assert(!s->reconnect_delay_timer);
     /*
@@ -258,6 +264,12 @@ static void nbd_client_attach_aio_context_bh(void *opaque)
     BlockDriverState *bs = opaque;
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
 
+    /*
+     * This runs in the (new, just attached) aio context of the @bs so
+     * accessing the stuff on @s is concurrency-free.
+     */
+    assert(qemu_get_current_aio_context() == bdrv_get_aio_context(bs));
+
     if (s->connection_co) {
         /*
          * The node is still drained, so we know the coroutine has yielded in
-- 
2.30.2