job: Add job_event_*()

Go through the Job layer in order to send QMP events. For the moment,
these functions only call a notifier in the BlockJob layer that sends
the existing commands.

This uses notifiers rather than JobDriver callbacks because internal
users of jobs won't receive QMP events, but might still be interested
in getting notified for the events.

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

blockjob.c

@@ -36,10 +36,6 @@
 #include "qemu/coroutine.h"
 #include "qemu/timer.h"
 
-static void block_job_event_cancelled(BlockJob *job);
-static void block_job_event_completed(BlockJob *job, const char *msg);
-static void block_job_event_pending(BlockJob *job);
-
 /* Transactional group of block jobs */
 struct BlockJobTxn {
 
@@ -352,13 +348,9 @@ static int block_job_finalize_single(BlockJob *job)
     /* Emit events only if we actually started */
     if (job_started(&job->job)) {
         if (job_is_cancelled(&job->job)) {
-            block_job_event_cancelled(job);
+            job_event_cancelled(&job->job);
         } else {
-            const char *msg = NULL;
+            job_event_completed(&job->job);
-            if (job->ret < 0) {
-                msg = strerror(-job->ret);
-            }
-            block_job_event_completed(job, msg);
         }
     }
 
@@ -504,7 +496,7 @@ static int block_job_transition_to_pending(BlockJob *job)
 {
     job_state_transition(&job->job, JOB_STATUS_PENDING);
     if (!job->job.auto_finalize) {
-        block_job_event_pending(job);
+        job_event_pending(&job->job);
     }
     return 0;
 }
@@ -712,8 +704,10 @@ static void block_job_iostatus_set_err(BlockJob *job, int error)
     }
 }
 
-static void block_job_event_cancelled(BlockJob *job)
+static void block_job_event_cancelled(Notifier *n, void *opaque)
 {
+    BlockJob *job = opaque;
+
     if (block_job_is_internal(job)) {
         return;
     }
@@ -726,12 +720,19 @@ static void block_job_event_cancelled(BlockJob *job)
                                         &error_abort);
 }
 
-static void block_job_event_completed(BlockJob *job, const char *msg)
+static void block_job_event_completed(Notifier *n, void *opaque)
 {
+    BlockJob *job = opaque;
+    const char *msg = NULL;
+
     if (block_job_is_internal(job)) {
         return;
     }
 
+    if (job->ret < 0) {
+        msg = strerror(-job->ret);
+    }
+
     qapi_event_send_block_job_completed(job_type(&job->job),
                                         job->job.id,
                                         job->len,
@@ -742,8 +743,10 @@ static void block_job_event_completed(BlockJob *job, const char *msg)
                                         &error_abort);
 }
 
-static void block_job_event_pending(BlockJob *job)
+static void block_job_event_pending(Notifier *n, void *opaque)
 {
+    BlockJob *job = opaque;
+
     if (block_job_is_internal(job)) {
         return;
     }
@@ -799,6 +802,16 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
     job->cb            = cb;
     job->opaque        = opaque;
 
+    job->finalize_cancelled_notifier.notify = block_job_event_cancelled;
+    job->finalize_completed_notifier.notify = block_job_event_completed;
+    job->pending_notifier.notify = block_job_event_pending;
+
+    notifier_list_add(&job->job.on_finalize_cancelled,
+                      &job->finalize_cancelled_notifier);
+    notifier_list_add(&job->job.on_finalize_completed,
+                      &job->finalize_completed_notifier);
+    notifier_list_add(&job->job.on_pending, &job->pending_notifier);
+
     error_setg(&job->blocker, "block device is in use by block job: %s",
                job_type_str(&job->job));
     block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);

include/block/blockjob.h

@@ -82,6 +82,15 @@ typedef struct BlockJob {
     /** Block other operations when block job is running */
     Error *blocker;
 
+    /** Called when a cancelled job is finalised. */
+    Notifier finalize_cancelled_notifier;
+
+    /** Called when a successfully completed job is finalised. */
+    Notifier finalize_completed_notifier;
+
+    /** Called when the job transitions to PENDING */
+    Notifier pending_notifier;
+
     /** BlockDriverStates that are involved in this block job */
     GSList *nodes;
 

include/qemu/job.h

@@ -105,6 +105,15 @@ typedef struct Job {
     /** True if this job should automatically dismiss itself */
     bool auto_dismiss;
 
+    /** Notifiers called when a cancelled job is finalised */
+    NotifierList on_finalize_cancelled;
+
+    /** Notifiers called when a successfully completed job is finalised */
+    NotifierList on_finalize_completed;
+
+    /** Notifiers called when the job transitions to PENDING */
+    NotifierList on_pending;
+
     /** Element of the list of jobs */
     QLIST_ENTRY(Job) job_list;
 } Job;
@@ -182,6 +191,15 @@ void job_ref(Job *job);
  */
 void job_unref(Job *job);
 
+/** To be called when a cancelled job is finalised. */
+void job_event_cancelled(Job *job);
+
+/** To be called when a successfully completed job is finalised. */
+void job_event_completed(Job *job);
+
+/** To be called when the job transitions to PENDING */
+void job_event_pending(Job *job);
+
 /**
  * Conditionally enter the job coroutine if the job is ready to run, not
  * already busy and fn() returns true. fn() is called while under the job_lock

job.c

@@ -215,6 +215,10 @@ void *job_create(const char *job_id, const JobDriver *driver, AioContext *ctx,
     job->auto_finalize = !(flags & JOB_MANUAL_FINALIZE);
     job->auto_dismiss  = !(flags & JOB_MANUAL_DISMISS);
 
+    notifier_list_init(&job->on_finalize_cancelled);
+    notifier_list_init(&job->on_finalize_completed);
+    notifier_list_init(&job->on_pending);
+
     job_state_transition(job, JOB_STATUS_CREATED);
     aio_timer_init(qemu_get_aio_context(), &job->sleep_timer,
                    QEMU_CLOCK_REALTIME, SCALE_NS,
@@ -247,6 +251,21 @@ void job_unref(Job *job)
     }
 }
 
+void job_event_cancelled(Job *job)
+{
+    notifier_list_notify(&job->on_finalize_cancelled, job);
+}
+
+void job_event_completed(Job *job)
+{
+    notifier_list_notify(&job->on_finalize_completed, job);
+}
+
+void job_event_pending(Job *job)
+{
+    notifier_list_notify(&job->on_pending, job);
+}
+
 void job_enter_cond(Job *job, bool(*fn)(Job *job))
 {
     if (!job_started(job)) {