[01/15] block/qed: add missing graph rdlock in qed_need_check_timer_entry

Commit Message

Emanuele Giuseppe Esposito Nov. 16, 2022, 2:07 p.m. UTC

This function is called in two different places:
- timer callback, which does not take the graph rdlock.
- bdrv_qed_drain_begin(), which is a .bdrv_drain_begin()
  callback that will soon take the lock.

Since it calls recursive functions that traverse the
graph, we need to protect them with the graph rdlock.

Signed-off-by: Emanuele Giuseppe Esposito <[e-mail]>
---
 block/qed.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/block/qed.c b/block/qed.c
index c2691a85b1..778b23d0f6 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -282,11 +282,13 @@  static void coroutine_fn qed_unplug_allocating_write_reqs(BDRVQEDState *s)
     qemu_co_mutex_unlock(&s->table_lock);
 }
 
+/* Called with graph rdlock taken */
 static void coroutine_fn qed_need_check_timer(BDRVQEDState *s)
 {
     int ret;
 
     trace_qed_need_check_timer_cb(s);
+    assert_bdrv_graph_readable();
 
     if (!qed_plug_allocating_write_reqs(s)) {
         return;
@@ -312,6 +314,7 @@  static void coroutine_fn qed_need_check_timer(BDRVQEDState *s)
 static void coroutine_fn qed_need_check_timer_entry(void *opaque)
 {
     BDRVQEDState *s = opaque;
+    GRAPH_RDLOCK_GUARD();
 
     qed_need_check_timer(opaque);
     bdrv_dec_in_flight(s->bs);