Reserve 0 for general use a token meaning that the fence doesn't belong to an ordered timeline (fence context).
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Gustavo Padovan gustavo@padovan.org Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: "Christian König" <christian.koenig@amd.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Alex Deucher alexander.deucher@amd.com --- drivers/dma-buf/dma-fence.c | 4 +++- include/linux/dma-fence.h | 2 ++ 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 0918d3f003d6..0646357ea350 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -36,8 +36,10 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_enable_signal); * fence context, this allows checking if fences belong to the same * context or not. One device can have multiple separate contexts, * and they're used if some engine can run independently of another. + * + * 0 is excluded and treated as a special DMA_FENCE_NO_CONTEXT. */ -static atomic64_t dma_fence_context_counter = ATOMIC64_INIT(0); +static atomic64_t dma_fence_context_counter = ATOMIC64_INIT(1);
/** * dma_fence_context_alloc - allocate an array of fence contexts diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 6048fa404e57..adfdc7fdd9c3 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -455,6 +455,8 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) return ret < 0 ? ret : 0; }
+#define DMA_FENCE_NO_CONTEXT ((u64)0) + u64 dma_fence_context_alloc(unsigned num);
#define DMA_FENCE_TRACE(f, fmt, args...) \