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blockjob: use deferred_to_main_loop to indicate the coroutine has ended

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All block jobs are using block_job_defer_to_main_loop as the final
step just before the coroutine terminates.  At this point,
block_job_enter should do nothing, but currently it restarts
the freed coroutine.

Now, the job->co states should probably be changed to an enum
(e.g. BEFORE_START, STARTED, YIELDED, COMPLETED) subsuming
block_job_started, job->deferred_to_main_loop and job->busy.
For now, this patch eliminates the problematic reenter by
removing the reset of job->deferred_to_main_loop (which served
no purpose, as far as I could see) and checking the flag in
block_job_enter.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20170508141310.8674-12-pbonzini@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-05-08 16:13:10 +02:00 committed by Jeff Cody
parent 4fb588e95b
commit eb05e011e2
2 changed files with 10 additions and 3 deletions
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10
blockjob.c
View File

@ -771,7 +771,14 @@ void block_job_resume_all(void)
void block_job_enter(BlockJob *job)
{
if (job->co && !job->busy) {
if (!block_job_started(job)) {
return;
}
if (job->deferred_to_main_loop) {
return;
}
if (!job->busy) {
bdrv_coroutine_enter(blk_bs(job->blk), job->co);
}
}
@ -899,7 +906,6 @@ static void block_job_defer_to_main_loop_bh(void *opaque)
aio_context_acquire(aio_context);
}
data->job->deferred_to_main_loop = false;
data->fn(data->job, data->opaque);
if (aio_context != data->aio_context) {

3
include/block/blockjob_int.h
View File

@ -241,7 +241,8 @@ typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
* @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
* This function must be called by the main job coroutine just before it
* returns. @fn is executed 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.
*