Commit a6dfa128 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk Committed by Ingo Molnar

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: default avatarIan Jackson <Ian.Jackson@eu.citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Acked-by: default avatarPrashant 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.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 18ecb3bf
......@@ -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
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment