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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2010-03-30 22:35:50 +0000
committerDavid S. Miller <davem@davemloft.net>2010-04-01 19:53:12 -0700
commit5acbbd428db47b12f137a8a2aa96b3c0a96b744e (patch)
tree20ffdc4e418a086411f6fa8ff4ead2d488bda8da /drivers/net/fec.c
parent4fd89b7af28292e190650b9b9bc4308658d81dd1 (diff)
net: change illegal_highdma to use dma_mask
Robert Hancock pointed out two problems about NETIF_F_HIGHDMA: -Many drivers only set the flag when they detect they can use 64-bit DMA, since otherwise they could receive DMA addresses that they can't handle (which on platforms without IOMMU/SWIOTLB support is fatal). This means that if 64-bit support isn't available, even buffers located below 4GB will get copied unnecessarily. -Some drivers set the flag even though they can't actually handle 64-bit DMA, which would mean that on platforms without IOMMU/SWIOTLB they would get a DMA mapping error if the memory they received happened to be located above 4GB. http://lkml.org/lkml/2010/3/3/530 We can use the dma_mask if we need bouncing or not here. Then we can safely fix drivers that misuse NETIF_F_HIGHDMA. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/fec.c')
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