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From 98c027dc5d49edb499749092d647edd620ca7d68 Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Tue, 25 Sep 2018 22:34:12 +0100
Subject: [PATCH 09/28] jobs: utilize job_exit shim

RH-Author: John Snow <jsnow@redhat.com>
Message-id: <20180925223431.24791-7-jsnow@redhat.com>
Patchwork-id: 82267
O-Subject: [RHEL8/rhel qemu-kvm PATCH 06/25] jobs: utilize job_exit shim
Bugzilla: 1632939
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

Utilize the job_exit shim by not calling job_defer_to_main_loop, and
where applicable, converting the deferred callback into the job_exit
callback.

This converts backup, stream, create, and the unit tests all at once.
Most of these jobs do not see any changes to the order in which they
clean up their resources, except the test-blockjob-txn test, which
now puts down its bs before job_completed is called.

This is safe for the same reason the reordering in the mirror job is
safe, because job_completed no longer runs under two locks, making
the unref safe even if it causes a flush.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-7-jsnow@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit eb23654dbe43b549ea2a9ebff9d8edf544d34a73)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 block/backup.c            | 16 ----------------
 block/create.c            | 14 +++-----------
 block/stream.c            | 22 +++++++---------------
 tests/test-bdrv-drain.c   |  6 ------
 tests/test-blockjob-txn.c | 11 ++---------
 tests/test-blockjob.c     | 10 ++++------
 6 files changed, 16 insertions(+), 63 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index a5bf699..08a5b74 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -380,18 +380,6 @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,
     }
 }
 
-typedef struct {
-    int ret;
-} BackupCompleteData;
-
-static void backup_complete(Job *job, void *opaque)
-{
-    BackupCompleteData *data = opaque;
-
-    job_completed(job, data->ret);
-    g_free(data);
-}
-
 static bool coroutine_fn yield_and_check(BackupBlockJob *job)
 {
     uint64_t delay_ns;
@@ -483,7 +471,6 @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
 static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
 {
     BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
-    BackupCompleteData *data;
     BlockDriverState *bs = blk_bs(job->common.blk);
     int64_t offset, nb_clusters;
     int ret = 0;
@@ -584,9 +571,6 @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
     qemu_co_rwlock_unlock(&job->flush_rwlock);
     hbitmap_free(job->copy_bitmap);
 
-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-    job_defer_to_main_loop(&job->common.job, backup_complete, data);
     return ret;
 }
 
diff --git a/block/create.c b/block/create.c
index 26a385c..9534121 100644
--- a/block/create.c
+++ b/block/create.c
@@ -34,28 +34,20 @@ typedef struct BlockdevCreateJob {
     Job common;
     BlockDriver *drv;
     BlockdevCreateOptions *opts;
-    int ret;
 } BlockdevCreateJob;
 
-static void blockdev_create_complete(Job *job, void *opaque)
-{
-    BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
-
-    job_completed(job, s->ret);
-}
-
 static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
 {
     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
+    int ret;
 
     job_progress_set_remaining(&s->common, 1);
-    s->ret = s->drv->bdrv_co_create(s->opts, errp);
+    ret = s->drv->bdrv_co_create(s->opts, errp);
     job_progress_update(&s->common, 1);
 
     qapi_free_BlockdevCreateOptions(s->opts);
-    job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);
 
-    return s->ret;
+    return ret;
 }
 
 static const JobDriver blockdev_create_job_driver = {
diff --git a/block/stream.c b/block/stream.c
index 26a7753..67e1e72 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -54,20 +54,16 @@ static int coroutine_fn stream_populate(BlockBackend *blk,
     return blk_co_preadv(blk, offset, qiov.size, &qiov, BDRV_REQ_COPY_ON_READ);
 }
 
-typedef struct {
-    int ret;
-} StreamCompleteData;
-
-static void stream_complete(Job *job, void *opaque)
+static void stream_exit(Job *job)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     BlockJob *bjob = &s->common;
-    StreamCompleteData *data = opaque;
     BlockDriverState *bs = blk_bs(bjob->blk);
     BlockDriverState *base = s->base;
     Error *local_err = NULL;
+    int ret = job->ret;
 
-    if (!job_is_cancelled(job) && bs->backing && data->ret == 0) {
+    if (!job_is_cancelled(job) && bs->backing && ret == 0) {
         const char *base_id = NULL, *base_fmt = NULL;
         if (base) {
             base_id = s->backing_file_str;
@@ -75,11 +71,11 @@ static void stream_complete(Job *job, void *opaque)
                 base_fmt = base->drv->format_name;
             }
         }
-        data->ret = bdrv_change_backing_file(bs, base_id, base_fmt);
+        ret = bdrv_change_backing_file(bs, base_id, base_fmt);
         bdrv_set_backing_hd(bs, base, &local_err);
         if (local_err) {
             error_report_err(local_err);
-            data->ret = -EPERM;
+            ret = -EPERM;
             goto out;
         }
     }
@@ -93,14 +89,12 @@ out:
     }
 
     g_free(s->backing_file_str);
-    job_completed(job, data->ret);
-    g_free(data);
+    job->ret = ret;
 }
 
 static int coroutine_fn stream_run(Job *job, Error **errp)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
-    StreamCompleteData *data;
     BlockBackend *blk = s->common.blk;
     BlockDriverState *bs = blk_bs(blk);
     BlockDriverState *base = s->base;
@@ -203,9 +197,6 @@ static int coroutine_fn stream_run(Job *job, Error **errp)
 
 out:
     /* Modify backing chain and close BDSes in main loop */
-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-    job_defer_to_main_loop(&s->common.job, stream_complete, data);
     return ret;
 }
 
@@ -215,6 +206,7 @@ static const BlockJobDriver stream_job_driver = {
         .job_type      = JOB_TYPE_STREAM,
         .free          = block_job_free,
         .run           = stream_run,
+        .exit          = stream_exit,
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
     },
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 8937894..403446e 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -496,11 +496,6 @@ typedef struct TestBlockJob {
     bool should_complete;
 } TestBlockJob;
 
-static void test_job_completed(Job *job, void *opaque)
-{
-    job_completed(job, 0);
-}
-
 static int coroutine_fn test_job_run(Job *job, Error **errp)
 {
     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
@@ -510,7 +505,6 @@ static int coroutine_fn test_job_run(Job *job, Error **errp)
         job_sleep_ns(&s->common.job, 100000);
     }
 
-    job_defer_to_main_loop(&s->common.job, test_job_completed, NULL);
     return 0;
 }
 
diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
index 82cedee..ef29f35 100644
--- a/tests/test-blockjob-txn.c
+++ b/tests/test-blockjob-txn.c
@@ -24,17 +24,11 @@ typedef struct {
     int *result;
 } TestBlockJob;
 
-static void test_block_job_complete(Job *job, void *opaque)
+static void test_block_job_exit(Job *job)
 {
     BlockJob *bjob = container_of(job, BlockJob, job);
     BlockDriverState *bs = blk_bs(bjob->blk);
-    int rc = (intptr_t)opaque;
 
-    if (job_is_cancelled(job)) {
-        rc = -ECANCELED;
-    }
-
-    job_completed(job, rc);
     bdrv_unref(bs);
 }
 
@@ -54,8 +48,6 @@ static int coroutine_fn test_block_job_run(Job *job, Error **errp)
         }
     }
 
-    job_defer_to_main_loop(job, test_block_job_complete,
-                           (void *)(intptr_t)s->rc);
     return s->rc;
 }
 
@@ -81,6 +73,7 @@ static const BlockJobDriver test_block_job_driver = {
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
         .run           = test_block_job_run,
+        .exit          = test_block_job_exit,
     },
 };
 
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index 408a226..ad4a65b 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -163,11 +163,10 @@ typedef struct CancelJob {
     bool completed;
 } CancelJob;
 
-static void cancel_job_completed(Job *job, void *opaque)
+static void cancel_job_exit(Job *job)
 {
-    CancelJob *s = opaque;
+    CancelJob *s = container_of(job, CancelJob, common.job);
     s->completed = true;
-    job_completed(job, 0);
 }
 
 static void cancel_job_complete(Job *job, Error **errp)
@@ -182,7 +181,7 @@ static int coroutine_fn cancel_job_run(Job *job, Error **errp)
 
     while (!s->should_complete) {
         if (job_is_cancelled(&s->common.job)) {
-            goto defer;
+            return 0;
         }
 
         if (!job_is_ready(&s->common.job) && s->should_converge) {
@@ -192,8 +191,6 @@ static int coroutine_fn cancel_job_run(Job *job, Error **errp)
         job_sleep_ns(&s->common.job, 100000);
     }
 
- defer:
-    job_defer_to_main_loop(&s->common.job, cancel_job_completed, s);
     return 0;
 }
 
@@ -204,6 +201,7 @@ static const BlockJobDriver test_cancel_driver = {
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
         .run           = cancel_job_run,
+        .exit          = cancel_job_exit,
         .complete      = cancel_job_complete,
     },
 };
-- 
1.8.3.1