[PATCH] s390: fix strnlen_user return value

strnlen_user is supposed to return then length count + 1 if no terminating \0
is found, and it should return 0 on exception.  Found by David Howells
<dhowells@redhat.com>.
Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/s390/lib/uaccess.S

@@ -198,12 +198,12 @@ __strnlen_user_asm:
 0:	srst	%r2,%r1
 	jo	0b
 	sacf	0
-	jh	1f		# \0 found in string ?
 	ahi	%r2,1		# strnlen_user result includes the \0
-1:	slr	%r2,%r3
+				# or return count+1 if \0 not found
+	slr	%r2,%r3
 	br	%r14
 2:	sacf	0
-	lhi	%r2,-EFAULT
+	slr	%r2,%r2		# return 0 on exception
 	br	%r14
 	.section __ex_table,"a"
 	.long	0b,2b

arch/s390/lib/uaccess64.S

@@ -194,12 +194,12 @@ __strnlen_user_asm:
 0:	srst	%r2,%r1
 	jo	0b
 	sacf	0
-	jh	1f		# \0 found in string ?
 	aghi	%r2,1		# strnlen_user result includes the \0
-1:	slgr	%r2,%r3
+				# or return count+1 if \0 not found
+	slgr	%r2,%r3
 	br	%r14
 2:	sacf	0
-	lghi	%r2,-EFAULT
+	slgr	%r2,%r2		# return 0 on exception
 	br	%r14
 	.section __ex_table,"a"
 	.quad	0b,2b