queue/drm-etnaviv-re-protect-fence-allocation-with-GPU-mut.patch

From ba66434b8c62588f4d40eab69ae2cded0f2eaa56 Mon Sep 17 00:00:00 2001
From: Lucas Stach <l.stach@pengutronix.de>
Date: Wed, 22 Mar 2017 12:07:23 +0100
Subject: [PATCH] drm/etnaviv: (re-)protect fence allocation with GPU mutex

commit f3cd1b064f1179d9e6188c6d67297a2360880e10 upstream.

The fence allocation needs to be protected by the GPU mutex, otherwise
the fence seqnos of concurrent submits might not match the insertion order
of the jobs in the kernel ring. This breaks the assumption that jobs
complete with monotonically increasing fence seqnos.

Fixes: d9853490176c (drm/etnaviv: take GPU lock later in the submit process)
CC: stable@vger.kernel.org #4.9+
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index b382cf505262..041e70abdc41 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1349,6 +1349,8 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu,
 		goto out_pm_put;
 	}
 
+	mutex_lock(&gpu->lock);
+
 	fence = etnaviv_gpu_fence_alloc(gpu);
 	if (!fence) {
 		event_free(gpu, event);
@@ -1356,8 +1358,6 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu,
 		goto out_pm_put;
 	}
 
-	mutex_lock(&gpu->lock);
-
 	gpu->event[event].fence = fence;
 	submit->fence = fence->seqno;
 	gpu->active_fence = submit->fence;
-- 
2.12.0