nfsd: Revert "nfsd: check for oversized NFSv2/v3 arguments"

This reverts commit 51f567777799 "nfsd: check for oversized NFSv2/v3
arguments", which breaks support for NFSv3 ACLs.

That patch was actually an earlier draft of a fix for the problem that
was eventually fixed by e6838a29ecb "nfsd: check for oversized NFSv2/v3
arguments".  But somehow I accidentally left this earlier draft in the
branch that was part of my 2.12 pull request.

Reported-by: Eryu Guan <eguan@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 9463102..11cef5a 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -336,7 +336,8 @@ xdr_argsize_check(struct svc_rqst *rqstp, __be32 *p)
 {
 	char *cp = (char *)p;
 	struct kvec *vec = &rqstp->rq_arg.head[0];
-	return cp == (char *)vec->iov_base + vec->iov_len;
+	return cp >= (char*)vec->iov_base
+		&& cp <= (char*)vec->iov_base + vec->iov_len;
 }
 
 static inline int