From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: daniel@ffwll.ch, linux-media@vger.kernel.org,
linaro-mm-sig@lists.linaro.org
Subject: [PATCH 2/2] dma-buf: clarify dma_fence_add_callback documentation
Date: Wed, 1 Sep 2021 14:02:40 +0200 [thread overview]
Message-ID: <20210901120240.7339-3-christian.koenig@amd.com> (raw)
In-Reply-To: <20210901120240.7339-1-christian.koenig@amd.com>
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 <christian.koenig@amd.com>
---
drivers/dma-buf/dma-fence.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
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.
--
2.25.1
next prev parent reply other threads:[~2021-09-01 12:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 12:02 Harden the dma-fence documentation a bit more Christian König
2021-09-01 12:02 ` [PATCH 1/2] dma-buf: clarify dma_fence_ops->wait documentation Christian König
2021-09-02 14:37 ` Daniel Vetter
2021-09-01 12:02 ` Christian König [this message]
2021-09-02 14:42 ` [PATCH 2/2] dma-buf: clarify dma_fence_add_callback documentation Daniel Vetter
2021-09-03 8:22 ` Christian König
-- strict thread matches above, loose matches on Subject: below --
2021-07-21 9:21 [PATCH 1/2] dma-buf: clarify dma_fence_ops->wait documentation Christian König
2021-07-21 9:21 ` [PATCH 2/2] dma-buf: clarify dma_fence_add_callback documentation Christian König
2021-07-21 11:52 ` Daniel Vetter
2021-07-21 13:18 ` Christian König
2021-07-21 13:36 ` Daniel Vetter
2021-07-21 13:56 ` Christian König
2021-07-21 14:37 ` Daniel Vetter
2021-07-21 14:54 ` Christian König
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