From 2ea9b58f0bc62445b7ace2381b4c4db7d5597e19 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 16 Jan 2013 19:25:51 +0100 Subject: [PATCH] aio: Fix return value of aio_poll() aio_poll() must return true if any work is still pending, even if it didn't make progress, so that bdrv_drain_all() doesn't stop waiting too early. The possibility of stopping early occasionally lead to a failed assertion in bdrv_drain_all(), when some in-flight request was missed and the function didn't really drain all requests. In order to make that change, the return value as specified in the function comment must change for blocking = false; fortunately, the return value of blocking = false callers is only used in test cases, so this change shouldn't cause any trouble. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi --- aio-posix.c | 3 ++- aio-win32.c | 3 ++- include/block/aio.h | 6 ++---- tests/test-aio.c | 4 ++-- 4 files changed, 8 insertions(+), 8 deletions(-) diff --git a/aio-posix.c b/aio-posix.c index 88d09e1cfb..fe4dbb4523 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -264,5 +264,6 @@ bool aio_poll(AioContext *ctx, bool blocking) } } - return progress; + assert(progress || busy); + return true; } diff --git a/aio-win32.c b/aio-win32.c index f5ea027f8c..38723bf1d3 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -214,5 +214,6 @@ bool aio_poll(AioContext *ctx, bool blocking) events[ret - WAIT_OBJECT_0] = events[--count]; } - return progress; + assert(progress || busy); + return true; } diff --git a/include/block/aio.h b/include/block/aio.h index 0933f05878..8eda924599 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -173,16 +173,14 @@ bool aio_pending(AioContext *ctx); * aio as a result of executing I/O completion or bh callbacks. * * If there is no pending AIO operation or completion (bottom half), - * return false. If there are pending bottom halves, return true. + * return false. If there are pending AIO operations of bottom halves, + * return true. * * If there are no pending bottom halves, but there are pending AIO * operations, it may not be possible to make any progress without * blocking. If @blocking is true, this function will wait until one * or more AIO events have completed, to ensure something has moved * before returning. - * - * If @blocking is false, this function will also return false if the - * function cannot make any progress without blocking. */ bool aio_poll(AioContext *ctx, bool blocking); diff --git a/tests/test-aio.c b/tests/test-aio.c index e4ebef76b9..c1738706cd 100644 --- a/tests/test-aio.c +++ b/tests/test-aio.c @@ -315,13 +315,13 @@ static void test_wait_event_notifier_noflush(void) event_notifier_set(&data.e); g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 1); - g_assert(!aio_poll(ctx, false)); + g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 1); event_notifier_set(&data.e); g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 2); - g_assert(!aio_poll(ctx, false)); + g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 2); event_notifier_set(&dummy.e); -- 2.42.0