Re: [Qemu-devel] [PATCH v5 05/14] blockjob: Introduce reference count

[Max Reitz]

On 07.09.2015 09:34, Fam Zheng wrote:
> So that block_job_complete_sync can be simplified.
> 
> Signed-off-by: Fam Zheng 
> ---
>  block/mirror.c   |  2 +-
>  blockjob.c   | 22 ++
>  include/block/blockjob.h | 18 +++---
>  3 files changed, 30 insertions(+), 12 deletions(-)

Reviewed-by: Max Reitz 



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[Qemu-devel] [PATCH v5 05/14] blockjob: Introduce reference count

[Fam Zheng]

So that block_job_complete_sync can be simplified.

Signed-off-by: Fam Zheng 
---
 block/mirror.c   |  2 +-
 blockjob.c   | 22 ++
 include/block/blockjob.h | 18 +++---
 3 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index a258926..3472ad4 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -736,7 +736,7 @@ static void mirror_start_job(BlockDriverState *bs, 
BlockDriverState *target,
 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
 if (!s->dirty_bitmap) {
 g_free(s->replaces);
-block_job_release(bs);
+block_job_unref(>common);
 return;
 }
 bdrv_set_enable_write_cache(s->target, true);
diff --git a/blockjob.c b/blockjob.c
index 62bb906..ec12887 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -58,6 +58,7 @@ void *block_job_create(const BlockJobDriver *driver, 
BlockDriverState *bs,
 job->cb= cb;
 job->opaque= opaque;
 job->busy  = true;
+job->refcnt= 1;
 bs->job = job;
 
 /* Only set speed when necessary to avoid NotSupported error */
@@ -66,7 +67,7 @@ void *block_job_create(const BlockJobDriver *driver, 
BlockDriverState *bs,
 
 block_job_set_speed(job, speed, _err);
 if (local_err) {
-block_job_release(bs);
+block_job_unref(job);
 error_propagate(errp, local_err);
 return NULL;
 }
@@ -74,14 +75,19 @@ void *block_job_create(const BlockJobDriver *driver, 
BlockDriverState *bs,
 return job;
 }
 
-void block_job_release(BlockDriverState *bs)
+void block_job_ref(BlockJob *job)
 {
-BlockJob *job = bs->job;
+++job->refcnt;
+}
 
-bs->job = NULL;
-bdrv_op_unblock_all(bs, job->blocker);
-error_free(job->blocker);
-g_free(job);
+void block_job_unref(BlockJob *job)
+{
+if (--job->refcnt == 0) {
+job->bs->job = NULL;
+bdrv_op_unblock_all(job->bs, job->blocker);
+error_free(job->blocker);
+g_free(job);
+}
 }
 
 void block_job_completed(BlockJob *job, int ret)
@@ -90,7 +96,7 @@ void block_job_completed(BlockJob *job, int ret)
 
 assert(bs->job == job);
 job->cb(job->opaque, ret);
-block_job_release(bs);
+block_job_unref(job);
 }
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index dd9d5e6..3e7ad21 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -122,6 +122,9 @@ struct BlockJob {
 
 /** The opaque value that is passed to the completion function.  */
 void *opaque;
+
+/** Reference count of the block job */
+int refcnt;
 };
 
 /**
@@ -166,12 +169,21 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType 
type, int64_t ns);
 void block_job_yield(BlockJob *job);
 
 /**
- * block_job_release:
+ * block_job_ref:
  * @bs: The block device.
  *
- * Release job resources when an error occurred or job completed.
+ * Grab a reference to the block job. Should be paired with block_job_unref.
  */
-void block_job_release(BlockDriverState *bs);
+void block_job_ref(BlockJob *job);
+
+/**
+ * block_job_unref:
+ * @bs: The block device.
+ *
+ * Release reference to the block job and release resources if it is the last
+ * reference.
+ */
+void block_job_unref(BlockJob *job);
 
 /**
  * block_job_completed:
-- 
2.4.3