[PATCH v2 3/6] block: convert bdrv_graph_wrlock() to AIO_WAIT_WHILE_UNLOCKED()
The following conversion is safe and does not change behavior: GLOBAL_STATE_CODE(); ... - AIO_WAIT_WHILE(qemu_get_aio_context(), ...); + AIO_WAIT_WHILE_UNLOCKED(NULL, ...); Since we're in GLOBAL_STATE_CODE(), qemu_get_aio_context() is our home thread's AioContext. Thus AIO_WAIT_WHILE() does not unlock the AioContext: if (ctx_ && in_aio_context_home_thread(ctx_)) {\ while ((cond)) { \ aio_poll(ctx_, true); \ waited_ = true;\ } \ And that means AIO_WAIT_WHILE_UNLOCKED(NULL, ...) can be substituted. Reviewed-by: Philippe Mathieu-Daudé Tested-by: Philippe Mathieu-Daudé Reviewed-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi --- block/graph-lock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/graph-lock.c b/block/graph-lock.c index 454c31e691..639526608f 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -127,7 +127,7 @@ void bdrv_graph_wrlock(void) * reader lock. */ qatomic_set(&has_writer, 0); -AIO_WAIT_WHILE(qemu_get_aio_context(), reader_count() >= 1); +AIO_WAIT_WHILE_UNLOCKED(NULL, reader_count() >= 1); qatomic_set(&has_writer, 1); /* -- 2.39.2
Re: [PATCH v2 3/6] block: convert bdrv_graph_wrlock() to AIO_WAIT_WHILE_UNLOCKED()
On Thu, 2023-03-09 at 14:08 -0500, Stefan Hajnoczi wrote: > The following conversion is safe and does not change behavior: > > GLOBAL_STATE_CODE(); > ... > - AIO_WAIT_WHILE(qemu_get_aio_context(), ...); > + AIO_WAIT_WHILE_UNLOCKED(NULL, ...); > > Since we're in GLOBAL_STATE_CODE(), qemu_get_aio_context() is our > home > thread's AioContext. Thus AIO_WAIT_WHILE() does not unlock the > AioContext: > > if (ctx_ && in_aio_context_home_thread(ctx_)) { \ > while ((cond)) { \ > aio_poll(ctx_, true); \ > waited_ = true; \ > } \ > > And that means AIO_WAIT_WHILE_UNLOCKED(NULL, ...) can be substituted. > > Reviewed-by: Philippe Mathieu-Daudé > Tested-by: Philippe Mathieu-Daudé > Reviewed-by: Kevin Wolf > Signed-off-by: Stefan Hajnoczi > --- > block/graph-lock.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Reviewed-by: Wilfred Mallawa > > diff --git a/block/graph-lock.c b/block/graph-lock.c > index 454c31e691..639526608f 100644 > --- a/block/graph-lock.c > +++ b/block/graph-lock.c > @@ -127,7 +127,7 @@ void bdrv_graph_wrlock(void) > * reader lock. > */ > qatomic_set(&has_writer, 0); > - AIO_WAIT_WHILE(qemu_get_aio_context(), reader_count() >= 1); > + AIO_WAIT_WHILE_UNLOCKED(NULL, reader_count() >= 1); > qatomic_set(&has_writer, 1); > > /*