drm/panfrost: Don't corrupt the queue mutex on open/close

The mutex within the panfrost_queue_state should have the lifetime of
the queue, however it was erroneously initialised/destroyed during
panfrost_job_{open,close} which is called every time a client
opens/closes the drm node.

Move the initialisation/destruction to panfrost_job_{init,fini} where it
belongs.

Fixes: 1a11a88c ("drm/panfrost: Fix job timeout handling")
Signed-off-by: Steven Price <steven.price@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201029170047.30564-1-steven.price@arm.com

drivers/gpu/drm/panfrost/panfrost_job.c

@@ -554,6 +554,8 @@ int panfrost_job_init(struct panfrost_device *pfdev)
 	}
 
 	for (j = 0; j < NUM_JOB_SLOTS; j++) {
+		mutex_init(&js->queue[j].lock);
+
 		js->queue[j].fence_context = dma_fence_context_alloc(1);
 
 		ret = drm_sched_init(&js->queue[j].sched,
@@ -584,8 +586,10 @@ void panfrost_job_fini(struct panfrost_device *pfdev)
 
 	job_write(pfdev, JOB_INT_MASK, 0);
 
-	for (j = 0; j < NUM_JOB_SLOTS; j++)
+	for (j = 0; j < NUM_JOB_SLOTS; j++) {
 		drm_sched_fini(&js->queue[j].sched);
+		mutex_destroy(&js->queue[j].lock);
+	}
 
 }
 
@@ -597,7 +601,6 @@ int panfrost_job_open(struct panfrost_file_priv *panfrost_priv)
 	int ret, i;
 
 	for (i = 0; i < NUM_JOB_SLOTS; i++) {
-		mutex_init(&js->queue[i].lock);
 		sched = &js->queue[i].sched;
 		ret = drm_sched_entity_init(&panfrost_priv->sched_entity[i],
 					    DRM_SCHED_PRIORITY_NORMAL, &sched,
@@ -614,10 +617,8 @@ void panfrost_job_close(struct panfrost_file_priv *panfrost_priv)
 	struct panfrost_job_slot *js = pfdev->js;
 	int i;
 
-	for (i = 0; i < NUM_JOB_SLOTS; i++) {
+	for (i = 0; i < NUM_JOB_SLOTS; i++)
 		drm_sched_entity_destroy(&panfrost_priv->sched_entity[i]);
-		mutex_destroy(&js->queue[i].lock);
-	}
 }
 
 int panfrost_job_is_idle(struct panfrost_device *pfdev)