[PATCH -mm] SWIOTLB: use iommu_is_span_boundary helper function

[FUJITA Tomonori]

iommu_is_span_boundary in lib/iommu-helper.c was exported for PARISC
IOMMUs (commit 3715863aa142c4f4c5208f5f3e5e9bac06006d2f). SWIOTLB can
use it instead of the homegrown function.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
 arch/ia64/Kconfig |    5 ++++-
 arch/x86/Kconfig  |    5 ++---
 lib/swiotlb.c     |   14 +++-----------
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 53b8410..6840a13 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -47,6 +47,9 @@ config MMU
 config SWIOTLB
        bool
 
+config IOMMU_HELPER
+       bool
+
 config GENERIC_LOCKBREAK
 	bool
 	default y
@@ -624,7 +627,7 @@ config IRQ_PER_CPU
 	default y
 
 config IOMMU_HELPER
-	def_bool (IA64_HP_ZX1 || IA64_HP_ZX1_SWIOTLB || IA64_GENERIC)
+	def_bool (IA64_HP_ZX1 || IA64_HP_ZX1_SWIOTLB || IA64_GENERIC || SWIOTLB)
 
 source "arch/ia64/hp/sim/Kconfig"
 
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1f44517..e6c01c2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -502,9 +502,6 @@ config CALGARY_IOMMU_ENABLED_BY_DEFAULT
 	  Calgary anyway, pass 'iommu=calgary' on the kernel command line.
 	  If unsure, say Y.
 
-config IOMMU_HELPER
-	def_bool (CALGARY_IOMMU || GART_IOMMU)
-
 # need this always selected by IOMMU for the VIA workaround
 config SWIOTLB
 	bool
@@ -515,6 +512,8 @@ config SWIOTLB
 	  access 32-bits of memory can be used on systems with more than
 	  3 GB of memory. If unsure, say Y.
 
+config IOMMU_HELPER
+	def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB)
 
 config NR_CPUS
 	int "Maximum number of CPUs (2-255)"
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 62c9a18..b50c7e0 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -31,6 +31,7 @@
 
 #include <linux/init.h>
 #include <linux/bootmem.h>
+#include <linux/iommu-helper.h>
 
 #define OFFSET(val,align) ((unsigned long)	\
 	                   ( (val) & ( (align) - 1)))
@@ -282,15 +283,6 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr)
 	return (addr & ~mask) != 0;
 }
 
-static inline unsigned int is_span_boundary(unsigned int index,
-					    unsigned int nslots,
-					    unsigned long offset_slots,
-					    unsigned long max_slots)
-{
-	unsigned long offset = (offset_slots + index) & (max_slots - 1);
-	return offset + nslots > max_slots;
-}
-
 /*
  * Allocates bounce buffer and returns its kernel virtual address.
  */
@@ -338,8 +330,8 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
 	wrap = index;
 
 	do {
-		while (is_span_boundary(index, nslots, offset_slots,
-				max_slots)) {
+		while (iommu_is_span_boundary(index, nslots, offset_slots,
+					      max_slots)) {
 			index += stride;
 			if (index >= io_tlb_nslabs)
 				index = 0;
-- 
1.5.3.7

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