qemu-kvm/SOURCES/kvm-job-Use-AIO_WAIT_WHILE-in-job_finish_sync.patch

78 lines
2.6 KiB
Diff

From 011fbd28d5f69f770357bcca6a767605de84fe95 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Wed, 10 Oct 2018 20:22:00 +0100
Subject: [PATCH 34/49] job: Use AIO_WAIT_WHILE() in job_finish_sync()
RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <20181010202213.7372-22-kwolf@redhat.com>
Patchwork-id: 82612
O-Subject: [RHEL-8 qemu-kvm PATCH 31/44] job: Use AIO_WAIT_WHILE() in job_finish_sync()
Bugzilla: 1637976
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
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 <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit de0fbe64806321fc3e6399bfab360553db87a41d)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
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