Add a function to simplify getting a single fence for all the fences in the dma_resv object.
Signed-off-by: Christian König christian.koenig@amd.com --- drivers/dma-buf/dma-resv.c | 50 ++++++++++++++++++++++++++++++++++++++ include/linux/dma-resv.h | 2 ++ 2 files changed, 52 insertions(+)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 0a69f4b7e6b5..f91ca023b550 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -34,6 +34,7 @@ */
#include <linux/dma-resv.h> +#include <linux/dma-fence-array.h> #include <linux/export.h> #include <linux/mm.h> #include <linux/sched/mm.h> @@ -721,6 +722,55 @@ int dma_resv_get_fences(struct dma_resv *obj, bool write, } EXPORT_SYMBOL_GPL(dma_resv_get_fences);
+/** + * dma_resv_get_singleton - Get a single fence for all the fences + * @obj: the reservation object + * @write: true if we should return all fences + * @fence: the resulting fence + * + * Get a single fence representing all the fences inside the resv object. + * Returns either 0 for success or -ENOMEM. + * + * Warning: This can't be used like this when adding the fence back to the resv + * object since that can lead to stack corruption when finalizing the + * dma_fence_array. + */ +int dma_resv_get_singleton(struct dma_resv *obj, bool write, + struct dma_fence **fence) +{ + struct dma_fence_array *array; + struct dma_fence **fences; + unsigned count; + int r; + + r = dma_resv_get_fences(obj, write, &count, &fences); + if (r) + return r; + + if (count == 0) { + *fence = NULL; + return 0; + } + + if (count == 1) { + *fence = fences[0]; + kfree(fences); + return 0; + } + + array = dma_fence_array_create(count, fences, + dma_fence_context_alloc(1), + 1, false); + if (!array) { + kfree(fences); + return -ENOMEM; + } + + *fence = &array->base; + return 0; +} +EXPORT_SYMBOL_GPL(dma_resv_get_singleton); + /** * dma_resv_wait_timeout - Wait on reservation's objects * shared and/or exclusive fences. diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 09b676b87c35..082f77b7bc63 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -440,6 +440,8 @@ void dma_resv_prune(struct dma_resv *obj); void dma_resv_prune_unlocked(struct dma_resv *obj); int dma_resv_get_fences(struct dma_resv *obj, bool write, unsigned int *num_fences, struct dma_fence ***fences); +int dma_resv_get_singleton(struct dma_resv *obj, bool write, + struct dma_fence **fence); int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src); long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr, unsigned long timeout);