drm/msm: Drop struct_mutex in submit path

It is sufficient to serialize on the submit queue now.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20210728010632.2633470-12-robdclark@gmail.comSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem_submit.c

@@ -709,7 +709,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	struct msm_drm_private *priv = dev->dev_private;
 	struct drm_msm_gem_submit *args = data;
 	struct msm_file_private *ctx = file->driver_priv;
-	struct msm_gem_submit *submit;
+	struct msm_gem_submit *submit = NULL;
 	struct msm_gpu *gpu = priv->gpu;
 	struct msm_gpu_submitqueue *queue;
 	struct msm_ringbuffer *ring;
@@ -753,7 +753,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	trace_msm_gpu_submit(pid_nr(pid), ring->id, submitid,
 		args->nr_bos, args->nr_cmds);
 
-	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	ret = mutex_lock_interruptible(&queue->lock);
 	if (ret)
 		goto out_post_unlock;
 
@@ -874,10 +874,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	 * Allocate an id which can be used by WAIT_FENCE ioctl to map back
 	 * to the underlying fence.
 	 */
-	mutex_lock(&queue->lock);
 	submit->fence_id = idr_alloc_cyclic(&queue->fence_idr,
 			submit->user_fence, 0, INT_MAX, GFP_KERNEL);
-	mutex_unlock(&queue->lock);
 	if (submit->fence_id < 0) {
 		ret = submit->fence_id = 0;
 		submit->fence_id = 0;
@@ -912,12 +910,12 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 	submit_cleanup(submit, !!ret);
 	if (has_ww_ticket)
 		ww_acquire_fini(&submit->ticket);
-	msm_gem_submit_put(submit);
 out_unlock:
 	if (ret && (out_fence_fd >= 0))
 		put_unused_fd(out_fence_fd);
-	mutex_unlock(&dev->struct_mutex);
-
+	mutex_unlock(&queue->lock);
+	if (submit)
+		msm_gem_submit_put(submit);
 out_post_unlock:
 	if (!IS_ERR_OR_NULL(post_deps)) {
 		for (i = 0; i < args->nr_out_syncobjs; ++i) {