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| author | Christian König <christian.koenig@amd.com> | 2021-07-20 15:37:35 +0200 |
|---|---|---|
| committer | Christian König <christian.koenig@amd.com> | 2021-09-03 10:12:12 +0200 |
| commit | 044e55b14657feb7522715ecec351990bd232ae0 (patch) | |
| tree | f867a37078f35a098119b3ce11ab8578ab0c39e4 /drivers/dma-buf | |
| parent | b83dcd753dbe42d5e7467ab65124f3d0a6002dc3 (diff) | |
| download | linux-stable-044e55b14657feb7522715ecec351990bd232ae0.tar.gz linux-stable-044e55b14657feb7522715ecec351990bd232ae0.tar.bz2 linux-stable-044e55b14657feb7522715ecec351990bd232ae0.zip | |
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')
| -rw-r--r-- | drivers/dma-buf/dma-fence.c | 13 |
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. |