From 164a101f28a53cd3db60ed874e7c3630e7988ed8 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 11 Apr 2013 16:56:50 +0200 Subject: aio: stop using .io_flush() Now that aio_poll() users check their termination condition themselves, it is no longer necessary to call .io_flush() handlers. The behavior of aio_poll() changes as follows: 1. .io_flush() is no longer invoked and file descriptors are *always* monitored. Previously returning 0 from .io_flush() would skip this file descriptor. Due to this change it is essential to check that requests are pending before calling qemu_aio_wait(). Failure to do so means we block, for example, waiting for an idle iSCSI socket to become readable when there are no requests. Currently all qemu_aio_wait()/aio_poll() callers check before calling. 2. aio_poll() now returns true if progress was made (BH or fd handlers executed) and false otherwise. Previously it would return true whenever 'busy', which means that .io_flush() returned true. The 'busy' concept no longer exists so just progress is returned. Due to this change we need to update tests/test-aio.c which asserts aio_poll() return values. Note that QEMU doesn't actually rely on these return values so only tests/test-aio.c cares. Note that ctx->notifier, the EventNotifier fd used for aio_notify(), is now handled as a special case. This is a little ugly but maintains aio_poll() semantics, i.e. aio_notify() does not count as 'progress' and aio_poll() avoids blocking when the user has not set any fd handlers yet. Patches after this remove .io_flush() handler code until we can finally drop the io_flush arguments to aio_set_fd_handler() and friends. Reviewed-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- tests/test-aio.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'tests') diff --git a/tests/test-aio.c b/tests/test-aio.c index 20bf5e69e1..1251952423 100644 --- a/tests/test-aio.c +++ b/tests/test-aio.c @@ -254,7 +254,7 @@ static void test_wait_event_notifier(void) EventNotifierTestData data = { .n = 0, .active = 1 }; event_notifier_init(&data.e, false); aio_set_event_notifier(ctx, &data.e, event_ready_cb, event_active_cb); - g_assert(aio_poll(ctx, false)); + g_assert(!aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 0); g_assert_cmpint(data.active, ==, 1); @@ -279,7 +279,7 @@ static void test_flush_event_notifier(void) EventNotifierTestData data = { .n = 0, .active = 10, .auto_set = true }; event_notifier_init(&data.e, false); aio_set_event_notifier(ctx, &data.e, event_ready_cb, event_active_cb); - g_assert(aio_poll(ctx, false)); + g_assert(!aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 0); g_assert_cmpint(data.active, ==, 10); @@ -313,7 +313,7 @@ static void test_wait_event_notifier_noflush(void) /* Until there is an active descriptor, aio_poll may or may not call * event_ready_cb. Still, it must not block. */ event_notifier_set(&data.e); - g_assert(!aio_poll(ctx, true)); + g_assert(aio_poll(ctx, true)); data.n = 0; /* An active event notifier forces aio_poll to look at EventNotifiers. */ @@ -323,13 +323,13 @@ 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); -- cgit v1.2.1