From: Oded Gabbay Date: Mon, 29 Jan 2018 15:31:40 +0000 (+0200) Subject: dma-fence: add comment for WARN_ON in dma_fence_release() X-Git-Tag: v4.17-rc1~185^2~15^2~23 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4518cd28d81fa4d2872268e4f8f7b35f387642cc;p=thirdparty%2Flinux.git dma-fence: add comment for WARN_ON in dma_fence_release() In dma_fence_release() there is a WARN_ON which could be triggered by several cases of wrong dma-fence usage. This patch adds a comment to explain two use-cases to help driver developers that use dma-fence and trigger that WARN_ON to better understand the reasons for it. v2: change to a more generic, one-liner comment Reviewed-by: Daniel Vetter Signed-off-by: Oded Gabbay --- diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 5d101c4053e05..4edb9fd3cf479 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -171,6 +171,7 @@ void dma_fence_release(struct kref *kref) trace_dma_fence_destroy(fence); + /* Failed to signal before release, could be a refcounting issue */ WARN_ON(!list_empty(&fence->cb_list)); if (fence->ops->release)