include/linux/io-mapping.h-mapping: use PHYS_PFN() macro in io_mapping_map_atomic_wc()

Use PHYS_PFN() macro in io_mapping_map_atomic_wc() instead of open coded
variant.

Link: http://lkml.kernel.org/r/20191209165624.56351-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/io-mapping.h

@@ -28,6 +28,7 @@ struct io_mapping {
 
 #ifdef CONFIG_HAVE_ATOMIC_IOMAP
 
+#include <linux/pfn.h>
 #include <asm/iomap.h>
 /*
  * For small address space machines, mapping large objects
@@ -64,12 +65,10 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping,
 			 unsigned long offset)
 {
 	resource_size_t phys_addr;
-	unsigned long pfn;
 
 	BUG_ON(offset >= mapping->size);
 	phys_addr = mapping->base + offset;
-	pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
-	return iomap_atomic_prot_pfn(pfn, mapping->prot);
+	return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot);
 }
 
 static inline void