mm: move MAP_SYNC to asm-generic/mman-common.h

This enables support for synchronous DAX fault on powerpc

The generic changes are added as part of b6fb293f ("mm: Define
MAP_SYNC and VM_SYNC flags")

Without this, mmap returns EOPNOTSUPP for MAP_SYNC with
MAP_SHARED_VALIDATE

Instead of adding MAP_SYNC with same value to
arch/powerpc/include/uapi/asm/mman.h, I am moving the #define to
asm-generic/mman-common.h.  Two architectures using mman-common.h
directly are sparc and powerpc.  We should be able to consloidate more
#defines to mman-common.h.  That can be done as a separate patch.

Link: http://lkml.kernel.org/r/20190528091120.13322-1-aneesh.kumar@linux.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/uapi/asm-generic/mman-common.h

@@ -20,7 +20,8 @@
 #define MAP_FIXED	0x10		/* Interpret addr exactly */
 #define MAP_ANONYMOUS	0x20		/* don't use a file */
 
-/* 0x0100 - 0x80000 flags are defined in asm-generic/mman.h */
+/* 0x0100 - 0x40000 flags are defined in asm-generic/mman.h */
+#define MAP_SYNC		0x080000 /* perform synchronous page faults for the mapping */
 #define MAP_FIXED_NOREPLACE	0x100000	/* MAP_FIXED which doesn't unmap underlying mapping */
 
 #define MAP_UNINITIALIZED 0x4000000	/* For anonymous mmap, memory could be

include/uapi/asm-generic/mman.h

@@ -13,7 +13,6 @@
 #define MAP_NONBLOCK	0x10000		/* do not block on IO */
 #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
-#define MAP_SYNC	0x80000		/* perform synchronous page faults for the mapping */
 
 /* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */