[PATCH] undo do_readv_writev() behavior change

Bugme bug 4326: http://bugme.osdl.org/show_bug.cgi?id=4326 reports:

executing the systemcall readv with Bad argument
->len == -1) it gives out error EFAULT instead of EINVAL 


Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/read_write.c b/fs/read_write.c
index 6be4b1a..c4c2bee 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -467,10 +467,10 @@
 		void __user *buf = iov[seg].iov_base;
 		ssize_t len = (ssize_t)iov[seg].iov_len;
 
-		if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
-			goto Efault;
 		if (len < 0)	/* size_t not fitting an ssize_t .. */
 			goto out;
+		if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
+			goto Efault;
 		tot_len += len;
 		if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
 			goto out;