swiotlb: use iommu_is_span_boundary helper function

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@lab.ntt.co.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 9 insertions, 15 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 3aa6c821449a..07f5d353b54a 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
@@ -615,7 +618,7 @@ 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 a12dbb2b93f3..1d9d874cba59 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -537,9 +537,6 @@ 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
@@ -550,6 +547,8 @@ 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 256c8445e54d..3c95922e51e7 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.
  */
@@ -337,8 +329,8 @@ 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;