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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-28 11:37:05 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-28 11:37:05 -0700 |
| commit | 901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544 (patch) | |
| tree | 21432df43fb614016657177e49ef6e6a3275fde4 /Documentation/core-api | |
| parent | ae085d7f9365de7da27ab5c0d16b12d51ea7fca9 (diff) | |
| download | lwn-901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544.tar.gz lwn-901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544.zip | |
Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""
Halil Pasic points out [1] that the full revert of that commit (revert
in bddac7c1e02b), and that a partial revert that only reverts the
problematic case, but still keeps some of the cleanups is probably
better. 
And that partial revert [2] had already been verified by Oleksandr
Natalenko to also fix the issue, I had just missed that in the long
discussion.
So let's reinstate the cleanups from commit aa6f8dcbab47 ("swiotlb:
rework "fix info leak with DMA_FROM_DEVICE""), and effectively only
revert the part that caused problems.
Link: https://lore.kernel.org/all/20220328013731.017ae3e3.pasic@linux.ibm.com/ [1]
Link: https://lore.kernel.org/all/20220324055732.GB12078@lst.de/ [2]
Link: https://lore.kernel.org/all/4386660.LvFx2qVVIh@natalenko.name/ [3]
Suggested-by: Halil Pasic <pasic@linux.ibm.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Christoph Hellwig" <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/core-api')
| -rw-r--r-- | Documentation/core-api/dma-attributes.rst | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/Documentation/core-api/dma-attributes.rst b/Documentation/core-api/dma-attributes.rst index 17706dc91ec9..1887d92e8e92 100644 --- a/Documentation/core-api/dma-attributes.rst +++ b/Documentation/core-api/dma-attributes.rst @@ -130,11 +130,3 @@ 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. |