From 92cedee6a6a3e6fcc3ffc0e3866baae5f6f76ac1 Mon Sep 17 00:00:00 2001 From: Christian König Date: Wed, 3 Nov 2021 10:02:08 +0100 Subject: dma-buf: add dma_resv_get_singleton v2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a function to simplify getting a single fence for all the fences in the dma_resv object. v2: fix ref leak in error handling Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-3-christian.koenig@amd.com --- drivers/dma-buf/dma-resv.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index be65522f0f47..ff16da0a54ec 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -34,6 +34,7 @@ */ #include +#include #include #include #include @@ -636,6 +637,59 @@ 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. + * + * Returns 0 on success and negative error values on failure. + */ +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) { + while (count--) + dma_fence_put(fences[count]); + 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. -- cgit v1.2.3