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authorDaniel Vetter <daniel.vetter@ffwll.ch>2018-05-03 16:25:52 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2018-07-03 13:12:57 +0200
commit418cc6ca06071e7b7d75c0d525d80a6f49a763d6 (patch)
tree12a8b278e184d4b5350248a47ce2f5208ea8a100 /include/linux/dma-fence.h
parent070473bcf703366e9acb14e172d5b6563cc07a26 (diff)
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dma-fence: Make ->wait callback optional
Almost everyone uses dma_fence_default_wait. v2: Also remove the BUG_ON(!ops->wait) (Chris). Reviewed-by: Christian König <christian.koenig@amd.com> (v1) Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20180503142603.28513-5-daniel.vetter@ffwll.ch
Diffstat (limited to 'include/linux/dma-fence.h')
-rw-r--r--include/linux/dma-fence.h13
1 files changed, 8 insertions, 5 deletions
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index c053d19e1e24..02dba8cd033d 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -191,11 +191,14 @@ struct dma_fence_ops {
/**
* @wait:
*
- * Custom wait implementation, or dma_fence_default_wait.
+ * Custom wait implementation, defaults to dma_fence_default_wait() if
+ * not set.
*
- * Must not be NULL, set to dma_fence_default_wait for default implementation.
- * the dma_fence_default_wait implementation should work for any fence, as long
- * as enable_signaling works correctly.
+ * The dma_fence_default_wait implementation should work for any fence, as long
+ * as @enable_signaling works correctly. This hook allows drivers to
+ * have an optimized version for the case where a process context is
+ * already available, e.g. if @enable_signaling for the general case
+ * needs to set up a worker thread.
*
* Must return -ERESTARTSYS if the wait is intr = true and the wait was
* interrupted, and remaining jiffies if fence has signaled, or 0 if wait
@@ -203,7 +206,7 @@ struct dma_fence_ops {
* which should be treated as if the fence is signaled. For example a hardware
* lockup could be reported like that.
*
- * This callback is mandatory.
+ * This callback is optional.
*/
signed long (*wait)(struct dma_fence *fence,
bool intr, signed long timeout);