drm/etnaviv: split fence lock

The fence lock currently protects two distinct things. It protects the fence
IDR from concurrent inserts and removes and also keeps drm_sched_job_arm and
drm_sched_entity_push_job in one atomic section to guarantee the fence seqno
monotonicity. Split the lock into those two functions.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

Author: lynxeye-dev

drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c

@@ -394,9 +394,9 @@ static void submit_cleanup(struct kref *kref)
 
 	if (submit->out_fence) {
 		/* first remove from IDR, so fence can not be found anymore */
-		mutex_lock(&submit->gpu->fence_lock);
+		mutex_lock(&submit->gpu->idr_lock);
 		idr_remove(&submit->gpu->fence_idr, submit->out_fence_id);
-		mutex_unlock(&submit->gpu->fence_lock);
+		mutex_unlock(&submit->gpu->idr_lock);
 		dma_fence_put(submit->out_fence);
 	}
 

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

@@ -1830,7 +1830,8 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 
 	gpu->dev = &pdev->dev;
 	mutex_init(&gpu->lock);
-	mutex_init(&gpu->fence_lock);
+	mutex_init(&gpu->sched_lock);
+	mutex_init(&gpu->idr_lock);
 
 	/* Map registers: */
 	gpu->mmio = devm_platform_ioremap_resource(pdev, 0);

drivers/gpu/drm/etnaviv/etnaviv_gpu.h

@@ -103,6 +103,7 @@ struct etnaviv_gpu {
 	struct etnaviv_chip_identity identity;
 	enum etnaviv_sec_mode sec_mode;
 	struct workqueue_struct *wq;
+	struct mutex sched_lock;
 	struct drm_gpu_scheduler sched;
 	bool initialized;
 	bool fe_running;
@@ -120,7 +121,7 @@ struct etnaviv_gpu {
 	u32 idle_mask;
 
 	/* Fencing support */
-	struct mutex fence_lock;
+	struct mutex idr_lock;
 	struct idr fence_idr;
 	u32 next_fence;
 	u32 completed_fence;

drivers/gpu/drm/etnaviv/etnaviv_sched.c

@@ -97,21 +97,24 @@ static const struct drm_sched_backend_ops etnaviv_sched_ops = {
 
 int etnaviv_sched_push_job(struct etnaviv_gem_submit *submit)
 {
+	struct etnaviv_gpu *gpu = submit->gpu;
 	int ret = 0;
 
 	/*
-	 * Hold the fence lock across the whole operation to avoid jobs being
+	 * Hold the sched lock across the whole operation to avoid jobs being
 	 * pushed out of order with regard to their sched fence seqnos as
 	 * allocated in drm_sched_job_arm.
 	 */
-	mutex_lock(&submit->gpu->fence_lock);
+	mutex_lock(&gpu->sched_lock);
 
 	drm_sched_job_arm(&submit->sched_job);
 
 	submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished);
-	submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr,
+	mutex_lock(&gpu->idr_lock);
+	submit->out_fence_id = idr_alloc_cyclic(&gpu->fence_idr,
 						submit->out_fence, 0,
 						INT_MAX, GFP_KERNEL);
+	mutex_unlock(&gpu->idr_lock);
 	if (submit->out_fence_id < 0) {
 		drm_sched_job_cleanup(&submit->sched_job);
 		ret = -ENOMEM;
@@ -124,7 +127,7 @@ int etnaviv_sched_push_job(struct etnaviv_gem_submit *submit)
 	drm_sched_entity_push_job(&submit->sched_job);
 
 out_unlock:
-	mutex_unlock(&submit->gpu->fence_lock);
+	mutex_unlock(&gpu->sched_lock);
 
 	return ret;
 }