From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Thu, 2 Nov 2017 22:03:35 +0200
Subject: drm/syncobj: Use proper methods for accessing rcu protected pointers
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Git-commit: 563eaf53317f2511f78217a1f8d785b8c8ed1cad
Patch-mainline: v4.16-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
Use rcu_dereference_protected() and rcu_assign_pointer() for accessing
the rcu protected syncobj->fence pointer. This eliminates several sparse
warnings.
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: linaro-mm-sig@lists.linaro.org
Cc: linux-media@vger.kernel.org
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171102200336.23347-4-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/drm_syncobj.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -106,7 +106,8 @@ static int drm_syncobj_fence_get_or_add_
* callback when a fence has already been set.
*/
if (syncobj->fence) {
- *fence = dma_fence_get(syncobj->fence);
+ *fence = dma_fence_get(rcu_dereference_protected(syncobj->fence,
+ lockdep_is_held(&syncobj->lock)));
ret = 1;
} else {
*fence = NULL;
@@ -168,8 +169,9 @@ void drm_syncobj_replace_fence(struct dr
spin_lock(&syncobj->lock);
- old_fence = syncobj->fence;
- syncobj->fence = fence;
+ old_fence = rcu_dereference_protected(syncobj->fence,
+ lockdep_is_held(&syncobj->lock));
+ rcu_assign_pointer(syncobj->fence, fence);
if (fence != old_fence) {
list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) {
@@ -640,7 +642,8 @@ static void syncobj_wait_syncobj_func(st
container_of(cb, struct syncobj_wait_entry, syncobj_cb);
/* This happens inside the syncobj lock */
- wait->fence = dma_fence_get(syncobj->fence);
+ wait->fence = dma_fence_get(rcu_dereference_protected(syncobj->fence,
+ lockdep_is_held(&syncobj->lock)));
wake_up_process(wait->task);
}