[PATCH 4.14 024/167] dma-buf: fix reservation_object_wait_timeout_rcu once more v2

Greg Kroah-Hartman
2018-02-21T12:47:15Z

From: Christian König <ckoenig.leichtzumerken@gmail.com>

commit 5bffee867df7494ecd32c1e6ec4e8fc934c521b7 upstream.

We need to set shared_count even if we already have a fence to wait for.

v2: init i to -1 as well

Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Tested-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180122200003.6665-1-christian.koenig@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/dma-buf/reservation.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -455,13 +455,15 @@ long reservation_object_wait_timeout_rcu
unsigned long timeout)
{
struct dma_fence *fence;
- unsigned seq, shared_count, i = 0;
+ unsigned seq, shared_count;
long ret = timeout ? timeout : 1;
+ int i;

retry:
shared_count = 0;
seq = read_seqcount_begin(&obj->seq);
rcu_read_lock();
+ i = -1;

fence = rcu_dereference(obj->fence_excl);
if (fence && !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
@@ -477,14 +479,14 @@ retry:
fence = NULL;
}

- if (!fence && wait_all) {
+ if (wait_all) {
struct reservation_object_list *fobj =
rcu_dereference(obj->fence);

if (fobj)
shared_count = fobj->shared_count;

- for (i = 0; i < shared_count; ++i) {
+ for (i = 0; !fence && i < shared_count; ++i) {
struct dma_fence *lfence = rcu_dereference(fobj->shared[i]);

if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,