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Commit 6142891a authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
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[PATCH] x86-64: Avoid unnecessary double bouncing for swiotlb 



PCI_DMA_BUS_IS_PHYS has to be zero even when the GART IOMMU is disabled
and the swiotlb is used. Otherwise the block layer does unnecessary
double bouncing.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 357e11d4

include/asm-x86_64/pci.h

+3 −3
Original line number Diff line number Diff line
@@ -50,10 +50,10 @@ extern int iommu_setup(char *opt); 
 * address space.  The networking and block device layers use

 * this boolean for bounce buffer decisions

 *

 * On AMD64 it mostly equals, but we set it to zero to tell some subsystems

 * that an IOMMU is available.

 * On x86-64 it mostly equals, but we set it to zero to tell some subsystems

 * that an hard or soft IOMMU is available.

 */

#define PCI_DMA_BUS_IS_PHYS	(no_iommu ? 1 : 0)

#define PCI_DMA_BUS_IS_PHYS 0



/*

 * x86-64 always supports DAC, but sometimes it is useful to force