Commit eb05e011 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Jeff Cody
Browse files

blockjob: use deferred_to_main_loop to indicate the coroutine has ended 



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: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170508141310.8674-12-pbonzini@redhat.com
Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
parent 4fb588e9

blockjob.c

+8 −2
Original line number Diff line number Diff line
@@ -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) {

include/block/blockjob_int.h

+2 −1
Original line number Diff line number Diff line
@@ -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.

 *