MLK-21644 crypto: tcrypt - workaround for overlapping src, dst AAD

This is a temporary workround for the case when:
-SWIOTLB is used for DMA bounce buffering AND
-data to be DMA-ed is mapped DMA_FROM_DEVICE and device only partially
overwrites the "original" data AND
-it's expected that the "original" data that was not overwritten
by the device to be untouched

As discussed in upstream, the proper fix should be:
-either an extension of the DMA API OR
-a workaround in the device driver (considering these cases are rarely
met in practice)

Since both alternatives are not trivial (to say the least),
add a workaround for the few cases matching the error conditions
listed above.

Link: https://lore.kernel.org/lkml/VI1PR0402MB348537CB86926B3E6D1DBE0A98070@VI1PR0402MB3485.eurprd04.prod.outlook.com/
Link: https://lore.kernel.org/lkml/20190522072018.10660-1-horia.geanta@nxp.com/
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Reviewed-by: Valentin Ciocoi Radulescu <valentin.ciocoi@nxp.com>
Reviewed-by: Iuliana Prodan <iuliana.prodan@nxp.com>

0 files changed, 0 insertions, 0 deletions