aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/kernel/dma/swiotlb.c
diff options
context:
space:
mode:
authorRobin Murphy <robin.murphy@arm.com>2018-11-21 16:00:50 +0000
committerChristoph Hellwig <hch@lst.de>2018-11-21 18:47:52 +0100
commitb34087157dd76e8d96e5e52808134a791ac61e57 (patch)
tree94aba2a4c0adae46be45c150ff5a57f15805d882 /kernel/dma/swiotlb.c
parentMerge tag 'mips_fixes_4.20_3' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux (diff)
downloadwireguard-linux-b34087157dd76e8d96e5e52808134a791ac61e57.tar.xz
wireguard-linux-b34087157dd76e8d96e5e52808134a791ac61e57.zip
dma-direct: Make DIRECT_MAPPING_ERROR viable for SWIOTLB
With the overflow buffer removed, we no longer have a unique address which is guaranteed not to be a valid DMA target to use as an error token. The DIRECT_MAPPING_ERROR value of 0 tries to at least represent an unlikely DMA target, but unfortunately there are already SWIOTLB users with DMA-able memory at physical address 0 which now gets falsely treated as a mapping failure and leads to all manner of misbehaviour. The best we can do to mitigate that is flip DIRECT_MAPPING_ERROR to the other commonly-used error value of all-bits-set, since the last single byte of memory is by far the least-likely-valid DMA target. Fixes: dff8d6c1ed58 ("swiotlb: remove the overflow buffer") Reported-by: John Stultz <john.stultz@linaro.org> Tested-by: John Stultz <john.stultz@linaro.org> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma/swiotlb.c')
0 files changed, 0 insertions, 0 deletions