]> git.dujemihanovic.xyz Git - linux.git/commit
dma: fix DMA sync for drivers not calling dma_set_mask*()
authorAlexander Lobakin <aleksander.lobakin@intel.com>
Thu, 9 May 2024 14:46:16 +0000 (16:46 +0200)
committerChristoph Hellwig <hch@lst.de>
Thu, 9 May 2024 17:00:29 +0000 (19:00 +0200)
commita6016aac5252da9d22a4dc0b98121b0acdf6d2f5
tree3c77ee2d2df0c886af162b6d85f6d562c3d6b1b7
parent163943ac00cb31ac1a88ce5f78a7e2ead37329ec
dma: fix DMA sync for drivers not calling dma_set_mask*()

There are several reports that the DMA sync shortcut broke non-coherent
devices.
dev->dma_need_sync is false after the &device allocation and if a driver
didn't call dma_set_mask*(), it will still be false even if the device
is not DMA-coherent and thus needs synchronizing. Due to historical
reasons, there's still a lot of drivers not calling it.
Invert the boolean, so that the sync will be performed by default and
the shortcut will be enabled only when calling dma_set_mask*().

Reported-by: Steven Price <steven.price@arm.com>
Closes: https://lore.kernel.org/lkml/010686f5-3049-46a1-8230-7752a1b433ff@arm.com
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/lkml/46160534-5003-4809-a408-6b3a3f4921e9@samsung.com
Fixes: f406c8e4b770. ("dma: avoid redundant calls for sync operations")
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Steven Price <steven.price@arm.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
include/linux/device.h
include/linux/dma-map-ops.h
include/linux/dma-mapping.h
kernel/dma/mapping.c
kernel/dma/swiotlb.c