Re: [PATCH 2/6] block: convert blk_exp_close_all_type() to AIO_WAIT_WHILE_UNLOCKED()

[Philippe Mathieu-Daudé]

On 2/3/23 14:08, Stefan Hajnoczi wrote:
> On Thu, Mar 02, 2023 at 11:36:03AM +0100, Philippe Mathieu-Daudé wrote:
> > On 1/3/23 21:57, Stefan Hajnoczi wrote:
> > > There is no change in behavior. Switch to AIO_WAIT_WHILE_UNLOCKED()
> > > instead of AIO_WAIT_WHILE() to document that this code has already been
> > > audited and converted. The AioContext argument is already NULL so
> > > aio_context_release() is never called anyway.
> >
> > Shouldn't we assert(ctx && unlock) in AIO_WAIT_WHILE_INTERNAL() then?
>
> Can you show where you'd add that assertion? It's not clear to me what
> the purpose is.

Without your series applied, using:

-- >8 --
diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h
index dd9a7f6461..dc372e4c16 100644
--- a/include/block/aio-wait.h
+++ b/include/block/aio-wait.h
@@ -82,6 +82,8 @@ extern AioWait global_aio_wait;
     bool waited_ = false;                                          \
     AioWait *wait_ = &global_aio_wait;                             \
     AioContext *ctx_ = (ctx);                                      \
+    assert("Use AIO_WAIT_WHILE_UNLOCKED()" && !unlock              \
+           || (ctx && strcmp(#ctx, "qemu_get_aio_context()")));    \
     /* Increment wait_->num_waiters before evaluating cond. */     \
     qatomic_inc(&wait_->num_waiters);                              \
     /* Paired with smp_mb in aio_wait_kick(). */                   \
---

I get:

Assertion failed: ("Use AIO_WAIT_WHILE_UNLOCKED()" && !1 || (((void*)0) 
&& strcmp("((void*)0)", "qemu_get_aio_context()"))), function 
blk_exp_close_all_type, file export.c, line 309.

-> [PATCH 2/6] block: convert blk_exp_close_all_type() to 
AIO_WAIT_WHILE_UNLOCKED()

Assertion failed: ("Use AIO_WAIT_WHILE_UNLOCKED()" && !1 || 
(qemu_get_aio_context() && strcmp("qemu_get_aio_context()", 
"qemu_get_aio_context()"))), function bdrv_graph_wrlock, file 
graph-lock.c, line 130.

-> [PATCH 3/6] block: convert bdrv_graph_wrlock() to 
AIO_WAIT_WHILE_UNLOCKED()

Assertion failed: ("Use AIO_WAIT_WHILE_UNLOCKED()" && !1 || (((void*)0) 
&& strcmp("((void*)0)", "qemu_get_aio_context()"))), function 
bdrv_drain_all_begin, file io.c, line 523.

-> [PATCH 4/6] block: convert bdrv_drain_all_begin() to 
AIO_WAIT_WHILE_UNLOCKED()