From 49110174f8835ec3d5ca7fc076ee1f51c18564fe Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 20 Feb 2015 17:26:51 +0100 Subject: AioContext: acquire/release AioContext during aio_poll This is the first step in pushing down acquire/release, and will let rfifolock drop the contention callback feature. Signed-off-by: Paolo Bonzini Reviewed-by: Stefan Hajnoczi Message-id: 1424449612-18215-3-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- include/block/aio.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'include/block/aio.h') diff --git a/include/block/aio.h b/include/block/aio.h index 0dc7a258e2..d2bb423de1 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -118,13 +118,14 @@ void aio_context_ref(AioContext *ctx); void aio_context_unref(AioContext *ctx); /* Take ownership of the AioContext. If the AioContext will be shared between - * threads, a thread must have ownership when calling aio_poll(). + * threads, and a thread does not want to be interrupted, it will have to + * take ownership around calls to aio_poll(). Otherwise, aio_poll() + * automatically takes care of calling aio_context_acquire and + * aio_context_release. * - * Note that multiple threads calling aio_poll() means timers, BHs, and - * callbacks may be invoked from a different thread than they were registered - * from. Therefore, code must use AioContext acquire/release or use - * fine-grained synchronization to protect shared state if other threads will - * be accessing it simultaneously. + * Access to timers and BHs from a thread that has not acquired AioContext + * is possible. Access to callbacks for now must be done while the AioContext + * is owned by the thread (FIXME). */ void aio_context_acquire(AioContext *ctx); -- cgit v1.2.3-55-g7522