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authorChristian König <christian.koenig@amd.com>2021-07-20 15:37:35 +0200
committerChristian König <christian.koenig@amd.com>2021-09-03 10:12:12 +0200
commit044e55b14657feb7522715ecec351990bd232ae0 (patch)
treef867a37078f35a098119b3ce11ab8578ab0c39e4 /drivers/dma-buf/dma-fence.c
parentb83dcd753dbe42d5e7467ab65124f3d0a6002dc3 (diff)
dma-buf: clarify dma_fence_add_callback documentation
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> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210901120240.7339-3-christian.koenig@amd.com
Diffstat (limited to 'drivers/dma-buf/dma-fence.c')
-rw-r--r--drivers/dma-buf/dma-fence.c13
1 files 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.