Changelov v3->v3.1

 - fixed comments. (mainly vread/vwrite description is updated.)
 - use KM_USER0 instead of KM_USER1
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Mike Smith <scgtrp@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmalloc.c

@@ -1669,10 +1669,13 @@ static int aligned_vread(char *buf, char *addr, unsigned long count)
 		 * kmap() and get small overhead in this access function.
 		 */
 		if (p) {
-			/* we can expect USR1 is not used */
-			void *map = kmap_atomic(p, KM_USER1);
+			/*
+			 * we can expect USER0 is not used (see vread/vwrite's
+			 * function description)
+			 */
+			void *map = kmap_atomic(p, KM_USER0);
 			memcpy(buf, map + offset, length);
-			kunmap_atomic(map, KM_USER1);
+			kunmap_atomic(map, KM_USER0);
 		} else
 			memset(buf, 0, length);
 
@@ -1705,10 +1708,13 @@ static int aligned_vwrite(char *buf, char *addr, unsigned long count)
 		 * kmap() and get small overhead in this access function.
 		 */
 		if (p) {
-			/* we can expect USR1 is not used */
-			void *map = kmap_atomic(p, KM_USER1);
+			/*
+			 * we can expect USER0 is not used (see vread/vwrite's
+			 * function description)
+			 */
+			void *map = kmap_atomic(p, KM_USER0);
 			memcpy(map + offset, buf, length);
-			kunmap_atomic(map, KM_USER1);
+			kunmap_atomic(map, KM_USER0);
 		}
 		addr += length;
 		buf += length;
@@ -1725,20 +1731,25 @@ static int aligned_vwrite(char *buf, char *addr, unsigned long count)
  *	@count:		number of bytes to be read.
  *
  *	Returns # of bytes which addr and buf should be increased.
- *	(same to count).
- *	If [addr...addr+count) doesn't includes any valid area, returns 0.
+ *	(same number to @count). Returns 0 if [addr...addr+count) doesn't
+ *	includes any intersect with alive vmalloc area.
  *
  *	This function checks that addr is a valid vmalloc'ed area, and
- *	copy data from that area to a given buffer. If the given memory range of
- *	[addr...addr+count) includes some valid address, data is copied to
+ *	copy data from that area to a given buffer. If the given memory range
+ *	of [addr...addr+count) includes some valid address, data is copied to
  *	proper area of @buf. If there are memory holes, they'll be zero-filled.
  *	IOREMAP area is treated as memory hole and no copy is done.
  *
- *	Note: In usual ops, vread() is never necessary because the caller should
- *	know vmalloc() area is valid and can use memcpy(). This is for routines
- *	which have to access vmalloc area without any informaion, as /dev/kmem.
+ *	If [addr...addr+count) doesn't includes any intersects with alive
+ *	vm_struct area, returns 0.
+ *	@buf should be kernel's buffer. Because	this function uses KM_USER0,
+ *	the caller should guarantee KM_USER0 is not used.
+ *
+ *	Note: In usual ops, vread() is never necessary because the caller
+ *	should know vmalloc() area is valid and can use memcpy().
+ *	This is for routines which have to access vmalloc area without
+ *	any informaion, as /dev/kmem.
  *
- *	The caller should guarantee KM_USER1 is not used.
  */
 
 long vread(char *buf, char *addr, unsigned long count)
@@ -1795,8 +1806,9 @@ finished:
  *	@count:		number of bytes to be read.
  *
  *	Returns # of bytes which addr and buf should be incresed.
- *	(same to count).
- *	If [addr...addr+count) doesn't includes any valid area, returns 0.
+ *	(same number to @count).
+ *	If [addr...addr+count) doesn't includes any intersect with valid
+ *	vmalloc area, returns 0.
  *
  *	This function checks that addr is a valid vmalloc'ed area, and
  *	copy data from a buffer to the given addr. If specified range of
@@ -1804,6 +1816,11 @@ finished:
  *	proper area of @buf. If there are memory holes, no copy to hole.
  *	IOREMAP area is treated as memory hole and no copy is done.
  *
+ *	If [addr...addr+count) doesn't includes any intersects with alive
+ *	vm_struct area, returns 0.
+ *	@buf should be kernel's buffer. Because	this function uses KM_USER0,
+ *	the caller should guarantee KM_USER0 is not used.
+ *
  *	Note: In usual ops, vwrite() is never necessary because the caller
  *	should know vmalloc() area is valid and can use memcpy().
  *	This is for routines which have to access vmalloc area without