dma-buf/fence: make fence context 64 bit v2

Fence contexts are created on the fly (for example) by the GPU scheduler used
in the amdgpu driver as a result of an userspace request. Because of this
userspace could in theory force a wrap around of the 32bit context number
if it doesn't behave well.

Avoid this by increasing the context number to 64bits. This way even when
userspace manages to allocate a billion contexts per second it takes more
than 500 years for the context number to wrap around.

v2: fix printf formats as well.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-2-git-send-email-deathsimple@vodafone.de

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/dma-buf/fence.c b/drivers/dma-buf/fence.c
index 7b05dbe9b296..4d51f9e83fa8 100644
--- a/drivers/dma-buf/fence.c
+++ b/drivers/dma-buf/fence.c
@@ -35,7 +35,7 @@ EXPORT_TRACEPOINT_SYMBOL(fence_emit);
  * context or not. One device can have multiple separate contexts,
  * and they're used if some engine can run independently of another.
  */
-static atomic_t fence_context_counter = ATOMIC_INIT(0);
+static atomic64_t fence_context_counter = ATOMIC64_INIT(0);
 
 /**
  * fence_context_alloc - allocate an array of fence contexts
@@ -44,10 +44,10 @@ static atomic_t fence_context_counter = ATOMIC_INIT(0);
  * This function will return the first index of the number of fences allocated.
  * The fence context is used for setting fence->context to a unique number.
  */
-unsigned fence_context_alloc(unsigned num)
+u64 fence_context_alloc(unsigned num)
 {
         BUG_ON(!num);
-        return atomic_add_return(num, &fence_context_counter) - num;
+        return atomic64_add_return(num, &fence_context_counter) - num;
 }
 EXPORT_SYMBOL(fence_context_alloc);
 
@@ -513,7 +513,7 @@ EXPORT_SYMBOL(fence_wait_any_timeout);
  */
 void
 fence_init(struct fence *fence, const struct fence_ops *ops,
-             spinlock_t *lock, unsigned context, unsigned seqno)
+             spinlock_t *lock, u64 context, unsigned seqno)
 {
         BUG_ON(!lock);
         BUG_ON(!ops || !ops->wait || !ops->enable_signaling ||