From 0e2f733addbf7702065cc18d38b67a1284d0c2be Mon Sep 17 00:00:00 2001 From: =?utf8?q?Christian=20K=C3=B6nig?= Date: Wed, 7 Aug 2019 12:31:48 +0200 Subject: [PATCH] dma-buf: make dma_fence structure a bit smaller v2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit We clear the callback list on kref_put so that by the time we release the fence it is unused. No one should be adding to the cb_list that they don't themselves hold a reference for. This small change is actually making the structure 16% smaller. v2: add the comment to the code as well. Signed-off-by: Christian König Reviewed-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/322916/ --- include/linux/dma-fence.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 05d29dbc7e62..bea1d05cf51e 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -65,8 +65,14 @@ struct dma_fence_cb; struct dma_fence { struct kref refcount; const struct dma_fence_ops *ops; - struct rcu_head rcu; - struct list_head cb_list; + /* We clear the callback list on kref_put so that by the time we + * release the fence it is unused. No one should be adding to the cb_list + * that they don't themselves hold a reference for. + */ + union { + struct rcu_head rcu; + struct list_head cb_list; + }; spinlock_t *lock; u64 context; u64 seqno; -- 2.30.2