2 files changed, 29 insertions, 18 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6f20718d3156..e60c59b81bdd 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1894,6 +1894,10 @@ config SYSVIPC_COMPAT
 endmenu
 
 
+config HAVE_ATOMIC_IOMAP
+        def_bool y
+        depends on X86_32
+
 source "net/Kconfig"
 
 source "drivers/Kconfig"
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
index 1b566993db6e..82df31726a54 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -33,86 +33,93 @@
 /* this struct isn't actually defined anywhere */
 struct io_mapping;
 
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_HAVE_ATOMIC_IOMAP
+
+/*
+ * For small address space machines, mapping large objects
+ * into the kernel virtual space isn't practical. Where
+ * available, use fixmap support to dynamically map pages
+ * of the object at run time.
+ */
 
-/* Create the io_mapping object*/
 static inline struct io_mapping *
 io_mapping_create_wc(unsigned long base, unsigned long size)
 {
-        return (struct io_mapping *) ioremap_wc(base, size);
+        return (struct io_mapping *) base;
 }
 
 static inline void
 io_mapping_free(struct io_mapping *mapping)
 {
-        iounmap(mapping);
 }
 
 /* Atomic map/unmap */
 static inline void *
 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
 {
-        return ((char *) mapping) + offset;
+        offset += (unsigned long) mapping;
+        return iomap_atomic_prot_pfn(offset >> PAGE_SHIFT, KM_USER0,
+                                     __pgprot(__PAGE_KERNEL_WC));
 }
 
 static inline void
 io_mapping_unmap_atomic(void *vaddr)
 {
+        iounmap_atomic(vaddr, KM_USER0);
 }
 
-/* Non-atomic map/unmap */
 static inline void *
 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
 {
-        return ((char *) mapping) + offset;
+        offset += (unsigned long) mapping;
+        return ioremap_wc(offset, PAGE_SIZE);
 }
 
 static inline void
 io_mapping_unmap(void *vaddr)
 {
+        iounmap(vaddr);
 }
 
-#endif /* CONFIG_X86_64 */
+#else
 
-#ifdef CONFIG_X86_32
+/* Create the io_mapping object*/
 static inline struct io_mapping *
 io_mapping_create_wc(unsigned long base, unsigned long size)
 {
-        return (struct io_mapping *) base;
+        return (struct io_mapping *) ioremap_wc(base, size);
 }
 
 static inline void
 io_mapping_free(struct io_mapping *mapping)
 {
+        iounmap(mapping);
 }
 
 /* Atomic map/unmap */
 static inline void *
 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
 {
-        offset += (unsigned long) mapping;
-        return iomap_atomic_prot_pfn(offset >> PAGE_SHIFT, KM_USER0,
-                                     __pgprot(__PAGE_KERNEL_WC));
+        return ((char *) mapping) + offset;
 }
 
 static inline void
 io_mapping_unmap_atomic(void *vaddr)
 {
-        iounmap_atomic(vaddr, KM_USER0);
 }
 
+/* Non-atomic map/unmap */
 static inline void *
 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
 {
-        offset += (unsigned long) mapping;
-        return ioremap_wc(offset, PAGE_SIZE);
+        return ((char *) mapping) + offset;
 }
 
 static inline void
 io_mapping_unmap(void *vaddr)
 {
-        iounmap(vaddr);
 }
-#endif /* CONFIG_X86_32 */
+
+#endif /* HAVE_ATOMIC_IOMAP */
 
 #endif /* _LINUX_IO_MAPPING_H */