From b6f3ea824f00bec7ebd1c36feb2ae65184384f36 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Vlad Yasevich Date: Thu, 12 Mar 2015 19:13:20 -0500 Subject: [CHANGE 24/33] aio: Fix return value of aio_poll() To: rhvirt-patches@redhat.com, jen@redhat.com RH-Author: Vlad Yasevich Message-id: <1426187601-21396-25-git-send-email-vyasevic@redhat.com> Patchwork-id: 64361 O-Subject: [RHEL6.7 qemu-kvm PATCH v2 24/25] aio: Fix return value of aio_poll() Bugzilla: 1005016 RH-Acked-by: Juan Quintela RH-Acked-by: Michael S. Tsirkin RH-Acked-by: Paolo Bonzini From: Kevin Wolf 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 (cherry picked from commit 2ea9b58f0bc62445b7ace2381b4c4db7d5597e19) Signed-off-by: Jeff E. Nelson Conflicts: include/block/aio.h tests/test-aio.c - Tests don't exists yet, and aio.h changes when into qemu-aio.h Signed-off-by: Vladislav Yasevich --- aio-posix.c | 3 ++- aio-win32.c | 3 ++- qemu-aio.h | 6 ++---- 3 files changed, 6 insertions(+), 6 deletions(-) Signed-off-by: Jeff E. Nelson --- aio-posix.c | 3 ++- aio-win32.c | 3 ++- qemu-aio.h | 6 ++---- 3 files changed, 6 insertions(+), 6 deletions(-) diff --git a/aio-posix.c b/aio-posix.c index 5387268..a5045a6 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -245,5 +245,6 @@ 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 e460bd8..367dd90 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -209,5 +209,6 @@ bool aio_poll(AioContext *ctx, bool blocking) } } - return progress; + assert(progress || busy); + return true; } diff --git a/qemu-aio.h b/qemu-aio.h index 540ef81..7a5b78a 100644 --- a/qemu-aio.h +++ b/qemu-aio.h @@ -169,16 +169,14 @@ 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 or 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); -- 2.1.0