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authorDaniel Vetter <daniel.vetter@ffwll.ch>2020-12-11 18:58:43 +0300
committerDaniel Vetter <daniel.vetter@ffwll.ch>2020-12-16 13:28:34 +0300
commitc545781e1c55ab680dcc49c37212d5327b9d6812 (patch)
tree14152db8d82354f45b4ff3e89270bc4b4010734e /include/linux/dma-buf.h
parent8ccf0a29af75326fb8e5ed6e51ff61e74b7ed2e4 (diff)
downloadlinux-c545781e1c55ab680dcc49c37212d5327b9d6812.tar.xz
dma-buf: doc polish for pin/unpin
Motivated by a discussion with Christian and Thomas: Try to untangle a bit what's relevant for importers and what's relevant for exporters. Also add an assert that really only dynamic importers use the api function, anything else doesn't make sense. Acked-by: Christian König <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: "Christian König" <christian.koenig@amd.com> Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20201211155843.3348718-4-daniel.vetter@ffwll.ch
Diffstat (limited to 'include/linux/dma-buf.h')
-rw-r--r--include/linux/dma-buf.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 43802a31b25d..628681bf6c99 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -86,13 +86,15 @@ struct dma_buf_ops {
* @pin:
*
* This is called by dma_buf_pin() and lets the exporter know that the
- * DMA-buf can't be moved any more.
+ * DMA-buf can't be moved any more. The exporter should pin the buffer
+ * into system memory to make sure it is generally accessible by other
+ * devices.
*
* This is called with the &dmabuf.resv object locked and is mutual
* exclusive with @cache_sgt_mapping.
*
- * This callback is optional and should only be used in limited use
- * cases like scanout and not for temporary pin operations.
+ * This is called automatically for non-dynamic importers from
+ * dma_buf_attach().
*
* Returns:
*