From dec7d421f85578b0949292336f784f55ac84812d Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 21 Oct 2014 12:03:54 +0100 Subject: blockjob: add block_job_defer_to_main_loop() Block jobs will run in the BlockDriverState's AioContext, which may not always be the QEMU main loop. There are some block layer APIs that are either not thread-safe or risk lock ordering problems. This includes bdrv_unref(), bdrv_close(), and anything that calls bdrv_drain_all(). The block_job_defer_to_main_loop() API allows a block job to schedule a function to run in the main loop with the BlockDriverState AioContext held. This function will be used to perform cleanup and backing chain manipulations in block jobs. Signed-off-by: Stefan Hajnoczi Reviewed-by: Max Reitz Message-id: 1413889440-32577-6-git-send-email-stefanha@redhat.com --- include/block/blockjob.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'include/block/blockjob.h') diff --git a/include/block/blockjob.h b/include/block/blockjob.h index 9694f130b0..b6d4ebbe03 100644 --- a/include/block/blockjob.h +++ b/include/block/blockjob.h @@ -315,4 +315,23 @@ void block_job_iostatus_reset(BlockJob *job); BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs, BlockdevOnError on_err, int is_read, int error); + +typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque); + +/** + * block_job_defer_to_main_loop: + * @job: The job + * @fn: The function to run in the main loop + * @opaque: The opaque value that is passed to @fn + * + * Execute a given function in the main loop with the BlockDriverState + * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and + * anything that uses bdrv_drain_all() in the main loop. + * + * The @job AioContext is held while @fn executes. + */ +void block_job_defer_to_main_loop(BlockJob *job, + BlockJobDeferToMainLoopFn *fn, + void *opaque); + #endif -- cgit v1.2.3