From: FUJITA Tomonori Date: Tue, 30 Mar 2010 22:35:50 +0000 (+0000) Subject: net: change illegal_highdma to use dma_mask X-Git-Tag: v2.6.35-rc1~473^2~618 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5acbbd428db47b12f137a8a2aa96b3c0a96b744e;p=pandora-kernel.git 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 Signed-off-by: David S. Miller --- Reading git-diff-tree failed