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Merge tag 'dma-mapping-5.17-1' of git://git.infradead.org/users/hch/dma-mapping

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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
This commit is contained in:
Linus Torvalds
2022-02-27 12:42:37 -08:00
parent 6676ba2a6d ddbd89deb7
commit 98f3e84f8d
3 changed files with 18 additions and 1 deletions
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8
Documentation/core-api/dma-attributes.rst
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@@ -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.