Commit-ID:  a6dfa128ce5c414ab46b1d690f7a1b8decb8526d
Gitweb:     http://git.kernel.org/tip/a6dfa128ce5c414ab46b1d690f7a1b8decb8526d
Author:     Konrad Rzeszutek Wilk <[email protected]>
AuthorDate: Fri, 17 Apr 2015 15:04:48 -0400
Committer:  Ingo Molnar <[email protected]>
CommitDate: Sat, 18 Apr 2015 14:36:49 +0200

config: Enable NEED_DMA_MAP_STATE by default when SWIOTLB is selected

A huge amount of NIC drivers use the DMA API, however if
compiled under 32-bit an very important part of the DMA API can
be ommitted leading to the drivers not working at all
(especially if used with 'swiotlb=force iommu=soft').

As Prashant Sreedharan explains it: "the driver [tg3] uses
DEFINE_DMA_UNMAP_ADDR(), dma_unmap_addr_set() to keep a copy of
the dma "mapping" and dma_unmap_addr() to get the "mapping"
value. On most of the platforms this is a no-op, but ... with
"iommu=soft and swiotlb=force" this house keeping is required,
... otherwise we pass 0 while calling pci_unmap_/pci_dma_sync_
instead of the DMA address."

As such enable this even when using 32-bit kernels.

Reported-by: Ian Jackson <[email protected]>
Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
Acked-by: David S. Miller <[email protected]>
Acked-by: Prashant Sreedharan <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Michael Chan <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index faff693..eb79036 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -177,7 +177,7 @@ config SBUS
 
 config NEED_DMA_MAP_STATE
        def_bool y
-       depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
+       depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
 
 config NEED_SG_DMA_LENGTH
        def_bool y
--
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