On 2018-08-24 00:08, John Snow wrote: > All jobs do the same thing when they leave their running loop: > - Store the return code in a structure > - wait to receive this structure in the main thread > - signal job completion via job_completed > > Few jobs do anything beyond exactly this. Consolidate this exit > logic for a net reduction in SLOC. > > More seriously, when we utilize job_defer_to_main_loop_bh to call > a function that calls job_completed, job_finalize_single will run > in a context where it has recursively taken the aio_context lock, > which can cause hangs if it puts down a reference that causes a flush. > > You can observe this in practice by looking at mirror_exit's careful > placement of job_completed and bdrv_unref calls. > > If we centralize job exiting, we can signal job completion from outside > of the aio_context, which should allow for job cleanup code to run with > only one lock, which makes cleanup callbacks less tricky to write. > > Signed-off-by: John Snow <js...@redhat.com> > --- > include/qemu/job.h | 11 +++++++++++ > job.c | 18 ++++++++++++++++++ > 2 files changed, 29 insertions(+)
Reviewed-by: Max Reitz <mre...@redhat.com>
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