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authorPaolo Bonzini <pbonzini@redhat.com>2016-10-27 12:49:05 +0200
committerFam Zheng <famz@redhat.com>2016-10-28 21:50:18 +0800
commitc9d1a56174339b0afdef63b7d151b38f4bb6dae5 (patch)
tree1eb8359be422f1abbf98c5781cee063163861f67 /util/qemu-thread-win32.c
parent9e944cb4744b527dd93aa989023739375a8880fb (diff)
downloadfocaccia-qemu-c9d1a56174339b0afdef63b7d151b38f4bb6dae5.tar.gz
focaccia-qemu-c9d1a56174339b0afdef63b7d151b38f4bb6dae5.zip
block: only call aio_poll on the current thread's AioContext
aio_poll is not thread safe; for example bdrv_drain can hang if
the last in-flight I/O operation is completed in the I/O thread after
the main thread has checked bs->in_flight.

The bug remains latent as long as all of it is called within
aio_context_acquire/aio_context_release, but this will change soon.

To fix this, if bdrv_drain is called from outside the I/O thread,
signal the main AioContext through a dummy bottom half.  The event
loop then only runs in the I/O thread.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Diffstat (limited to 'util/qemu-thread-win32.c')
0 files changed, 0 insertions, 0 deletions