drm/amdgpu: fix incorrect use of drm_file->pid

That's the PID of the creator of the file (usually the X server) and not
the end user of the file.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
CC: stable@vger.kernel.org

drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c

@@ -55,7 +55,6 @@ static int amdgpu_sched_process_priority_override(struct amdgpu_device *adev,
 {
 	struct file *filp = fget(fd);
 	struct drm_file *file;
-	struct pid *pid;
 	struct amdgpu_fpriv *fpriv;
 	struct amdgpu_ctx *ctx;
 	uint32_t id;
@@ -63,20 +62,10 @@ static int amdgpu_sched_process_priority_override(struct amdgpu_device *adev,
 	if (!filp)
 		return -EINVAL;
 
-	pid = get_pid(((struct drm_file *)filp->private_data)->pid);
-
-	mutex_lock(&adev->ddev->filelist_mutex);
-	list_for_each_entry(file, &adev->ddev->filelist, lhead) {
-		if (file->pid != pid)
-			continue;
-
-		fpriv = file->driver_priv;
-		idr_for_each_entry(&fpriv->ctx_mgr.ctx_handles, ctx, id)
-				amdgpu_ctx_priority_override(ctx, priority);
-	}
-	mutex_unlock(&adev->ddev->filelist_mutex);
-
-	put_pid(pid);
+	file = filp->private_data;
+	fpriv = file->driver_priv;
+	idr_for_each_entry(&fpriv->ctx_mgr.ctx_handles, ctx, id)
+		amdgpu_ctx_priority_override(ctx, priority);
 
 	fput(filp);