job: Add reference counting

This moves reference counting from BlockJob to Job.

In order to keep calling the BlockJob cleanup code when the job is
deleted via job_unref(), introduce a new JobDriver.free callback. Every
block job must use block_job_free() for this callback, this is asserted
in block_job_create().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

3 files changed, 24 insertions, 23 deletions

diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 01cdee6..087e782 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -132,9 +132,6 @@ typedef struct BlockJob {
     /** The opaque value that is passed to the completion function.  */
     void *opaque;
 
-    /** Reference count of the block job */
-    int refcnt;
-
     /** True when job has reported completion by calling block_job_completed. */
     bool completed;
 
@@ -400,24 +397,6 @@ void block_job_iostatus_reset(BlockJob *job);
 BlockJobTxn *block_job_txn_new(void);
 
 /**
- * block_job_ref:
- *
- * Add a reference to BlockJob refcnt, it will be decreased with
- * block_job_unref, and then be freed if it comes to be the last
- * reference.
- */
-void block_job_ref(BlockJob *job);
-
-/**
- * block_job_unref:
- *
- * Release a reference that was previously acquired with block_job_ref
- * or block_job_create. If it's the last reference to the object, it will be
- * freed.
- */
-void block_job_unref(BlockJob *job);
-
-/**
  * block_job_txn_unref:
  *
  * Release a reference that was previously acquired with block_job_txn_add_job
diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index 1e62d6d..6f0fe3c 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -144,6 +144,13 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
                        BlockCompletionFunc *cb, void *opaque, Error **errp);
 
 /**
+ * block_job_free:
+ * Callback to be used for JobDriver.free in all block jobs. Frees block job
+ * specific resources in @job.
+ */
+void block_job_free(Job *job);
+
+/**
  * block_job_sleep_ns:
  * @job: The job that calls the function.
  * @ns: How many nanoseconds to stop for.
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 0b78778..0751e2a 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -41,6 +41,9 @@ typedef struct Job {
     /** The type of this job. */
     const JobDriver *driver;
 
+    /** Reference count of the block job */
+    int refcnt;
+
     /** Current state; See @JobStatus for details. */
     JobStatus status;
 
@@ -57,6 +60,9 @@ struct JobDriver {
 
     /** Enum describing the operation */
     JobType job_type;
+
+    /** Called when the job is freed */
+    void (*free)(Job *job);
 };
 
 
@@ -69,8 +75,17 @@ struct JobDriver {
  */
 void *job_create(const char *job_id, const JobDriver *driver, Error **errp);
 
-/** Frees the @job object. */
-void job_delete(Job *job);
+/**
+ * Add a reference to Job refcnt, it will be decreased with job_unref, and then
+ * be freed if it comes to be the last reference.
+ */
+void job_ref(Job *job);
+
+/**
+ * Release a reference that was previously acquired with job_ref() or
+ * job_create(). If it's the last reference to the object, it will be freed.
+ */
+void job_unref(Job *job);
 
 /** Returns the JobType of a given Job. */
 JobType job_type(const Job *job);