From 044e55b14657feb7522715ecec351990bd232ae0 Mon Sep 17 00:00:00 2001 From: Christian König Date: Tue, 20 Jul 2021 15:37:35 +0200 Subject: dma-buf: clarify dma_fence_add_callback documentation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit That the caller doesn't need to keep a reference is rather risky and not defensive at all. Especially dma_buf_poll got that horrible wrong, so better remove that sentence and also clarify that the callback might be called in atomic or interrupt context. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210901120240.7339-3-christian.koenig@amd.com --- drivers/dma-buf/dma-fence.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index ce0f5eff575d..1e82ecd443fa 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -616,20 +616,17 @@ EXPORT_SYMBOL(dma_fence_enable_sw_signaling); * @cb: the callback to register * @func: the function to call * + * Add a software callback to the fence. The caller should keep a reference to + * the fence. + * * @cb will be initialized by dma_fence_add_callback(), no initialization * by the caller is required. Any number of callbacks can be registered * to a fence, but a callback can only be registered to one fence at a time. * - * Note that the callback can be called from an atomic context. If - * fence is already signaled, this function will return -ENOENT (and + * If fence is already signaled, this function will return -ENOENT (and * *not* call the callback). * - * Add a software callback to the fence. Same restrictions apply to - * refcount as it does to dma_fence_wait(), however the caller doesn't need to - * keep a refcount to fence afterward dma_fence_add_callback() has returned: - * when software access is enabled, the creator of the fence is required to keep - * the fence alive until after it signals with dma_fence_signal(). The callback - * itself can be called from irq context. + * Note that the callback can be called from an atomic context or irq context. * * Returns 0 in case of success, -ENOENT if the fence is already signaled * and -EINVAL in case of error. -- cgit