x86: i915 needs pgprot_writecombine() and is_io_mapping_possible()

Impact: build fix

Theodore Ts reported that the i915 driver needs these symbols:

 ERROR: "pgprot_writecombine" [drivers/gpu/drm/i915/i915.ko] undefined!
 ERROR: "is_io_mapping_possible" [drivers/gpu/drm/i915/i915.ko] undefined!

Reported-by: Theodore Ts'o <tytso@mit.edu> wrote:
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 11 deletions

diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index 6c2b1af16926..04102d42ff42 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -20,23 +20,16 @@
 #include <asm/pat.h>
 #include <linux/module.h>
 
-#ifdef CONFIG_X86_PAE
-int
-is_io_mapping_possible(resource_size_t base, unsigned long size)
-{
-        return 1;
-}
-#else
-int
-is_io_mapping_possible(resource_size_t base, unsigned long size)
+int is_io_mapping_possible(resource_size_t base, unsigned long size)
 {
+#ifndef CONFIG_X86_PAE
         /* There is no way to map greater than 1 << 32 address without PAE */
         if (base + size > 0x100000000ULL)
                 return 0;
-
+#endif
         return 1;
 }
-#endif
+EXPORT_SYMBOL_GPL(is_io_mapping_possible);
 
 /* Map 'pfn' using fixed map 'type' and protections 'prot'
  */