summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2022-02-27 12:42:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-02-27 12:42:37 -0800
commit98f3e84f8df66f1ac9d04b6d8093993c9bfd69e6 (patch)
tree2b63116b52a5ba74ee2565b3f13454b300947777 /Documentation
parent6676ba2a6df6864a6b7b11f20166026e2201b627 (diff)
parentddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e (diff)
Merge tag 'dma-mapping-5.17-1' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fix from Christoph Hellwig: - fix a swiotlb info leak (Halil Pasic) * tag 'dma-mapping-5.17-1' of git://git.infradead.org/users/hch/dma-mapping: swiotlb: fix info leak with DMA_FROM_DEVICE
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/core-api/dma-attributes.rst8
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/core-api/dma-attributes.rst b/Documentation/core-api/dma-attributes.rst
index 1887d92e8e92..17706dc91ec9 100644
--- a/Documentation/core-api/dma-attributes.rst
+++ b/Documentation/core-api/dma-attributes.rst
@@ -130,3 +130,11 @@ accesses to DMA buffers in both privileged "supervisor" and unprivileged
subsystem that the buffer is fully accessible at the elevated privilege
level (and ideally inaccessible or at least read-only at the
lesser-privileged levels).
+
+DMA_ATTR_OVERWRITE
+------------------
+
+This is a hint to the DMA-mapping subsystem that the device is expected to
+overwrite the entire mapped size, thus the caller does not require any of the
+previous buffer contents to be preserved. This allows bounce-buffering
+implementations to optimise DMA_FROM_DEVICE transfers.