um: kill pfn_t

The core has developed a need for a "pfn_t" type [1].  Convert the usage
of pfn_t by usermode-linux to an unsigned long, and update pfn_to_phys()
to drop its expectation of a typed pfn.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/include/asm/page.h

@@ -18,6 +18,7 @@
 
 struct page;
 
+#include <linux/pfn.h>
 #include <linux/types.h>
 #include <asm/vm-flags.h>
 
@@ -52,7 +53,6 @@ typedef struct { unsigned long pgd; } pgd_t;
 #define pmd_val(x)	((x).pmd)
 #define __pmd(x) ((pmd_t) { (x) } )
 
-typedef unsigned long long pfn_t;
 typedef unsigned long long phys_t;
 
 #else
@@ -76,7 +76,6 @@ typedef struct { unsigned long pmd; } pmd_t;
 #define pte_is_zero(p) (!((p).pte & ~_PAGE_NEWPAGE))
 #define pte_set_val(p, phys, prot) (p).pte = (phys | pgprot_val(prot))
 
-typedef unsigned long pfn_t;
 typedef unsigned long phys_t;
 
 #endif
@@ -109,8 +108,8 @@ extern unsigned long uml_physmem;
 #define __pa(virt) to_phys((void *) (unsigned long) (virt))
 #define __va(phys) to_virt((unsigned long) (phys))
 
-#define phys_to_pfn(p) ((pfn_t) ((p) >> PAGE_SHIFT))
-#define pfn_to_phys(pfn) ((phys_t) ((pfn) << PAGE_SHIFT))
+#define phys_to_pfn(p) ((p) >> PAGE_SHIFT)
+#define pfn_to_phys(pfn) PFN_PHYS(pfn)
 
 #define pfn_valid(pfn) ((pfn) < max_mapnr)
 #define virt_addr_valid(v) pfn_valid(phys_to_pfn(__pa(v)))