[PATCH 4.0 01/55] config: Enable NEED_DMA_MAP_STATE by default when SWIOTLB is selected

Greg Kroah-Hartman
2015-07-08T08:19:20Z

From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

commit a6dfa128ce5c414ab46b1d690f7a1b8decb8526d upstream.

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 <Ian.Jackson@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Prashant Sreedharan <prashant@broadcom.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: cascardo@linux.vnet.ibm.com
Cc: david.vrabel@citrix.com
Cc: sanjeevb@broadcom.com
Cc: siva.kallam@broadcom.com
Cc: vyasevich@gmail.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/20150417190448.GA9462@l.oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- 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