From 1c16ba251ec8d0bf64ee34a0ef71b5912907de12 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 14 Sep 2018 10:55:29 +0200 Subject: [PATCH 38/49] job: Use AIO_WAIT_WHILE() in job_finish_sync() RH-Author: Kevin Wolf Message-id: <20180914105540.18077-32-kwolf@redhat.com> Patchwork-id: 82184 O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 31/42] job: Use AIO_WAIT_WHILE() in job_finish_sync() Bugzilla: 1601212 RH-Acked-by: John Snow RH-Acked-by: Max Reitz RH-Acked-by: Fam Zheng job_finish_sync() needs to release the AioContext lock of the job before calling aio_poll(). Otherwise, callbacks called by aio_poll() would possibly take the lock a second time and run into a deadlock with a nested AIO_WAIT_WHILE() call. Also, job_drain() without aio_poll() isn't necessarily enough to make progress on a job, it could depend on bottom halves to be executed. Combine both open-coded while loops into a single AIO_WAIT_WHILE() call that solves both of these problems. Signed-off-by: Kevin Wolf Reviewed-by: Fam Zheng Reviewed-by: Max Reitz Signed-off-by: Miroslav Rezanina --- job.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/job.c b/job.c index 5a0ccc7..47b5a11 100644 --- a/job.c +++ b/job.c @@ -29,6 +29,7 @@ #include "qemu/job.h" #include "qemu/id.h" #include "qemu/main-loop.h" +#include "block/aio-wait.h" #include "trace-root.h" #include "qapi/qapi-events-job.h" @@ -957,6 +958,7 @@ void job_complete(Job *job, Error **errp) int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp) { Error *local_err = NULL; + AioWait dummy_wait = {}; int ret; job_ref(job); @@ -969,14 +971,10 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp) job_unref(job); return -EBUSY; } - /* job_drain calls job_enter, and it should be enough to induce progress - * until the job completes or moves to the main thread. */ - while (!job->deferred_to_main_loop && !job_is_completed(job)) { - job_drain(job); - } - while (!job_is_completed(job)) { - aio_poll(qemu_get_aio_context(), true); - } + + AIO_WAIT_WHILE(&dummy_wait, job->aio_context, + (job_drain(job), !job_is_completed(job))); + ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret; job_unref(job); return ret; -- 1.8.3.1