lockd: eliminate duplicate nlmsvc_lookup_host call from nlmsvc_testlock

nlmsvc_testlock calls nlmsvc_lookup_host to find a nlm_host struct. The
callers of this functions, however, call nlmsvc_retrieve_args or
nlm4svc_retrieve_args, which also return a nlm_host struct.

Change nlmsvc_testlock to take a host arg instead of calling
nlmsvc_lookup_host itself and change the callers to pass a pointer to
the nlm_host they've already found.

We take a reference to host in the place where nlmsvc_testlock()
previous did a new lookup, so the reference counting is unchanged from
before.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/lockd/svc4proc.c

@@ -99,7 +99,7 @@ nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_args *argp,
 		return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;
 
 	/* Now check for conflicting locks */
-	resp->status = nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie);
+	resp->status = nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock, &resp->cookie);
 	if (resp->status == nlm_drop_reply)
 		rc = rpc_drop_reply;
 	else

fs/lockd/svclock.c

@@ -460,8 +460,8 @@ out:
  */
 __be32
 nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
-		struct nlm_lock *lock, struct nlm_lock *conflock,
-		struct nlm_cookie *cookie)
+		struct nlm_host *host, struct nlm_lock *lock,
+		struct nlm_lock *conflock, struct nlm_cookie *cookie)
 {
 	struct nlm_block 	*block = NULL;
 	int			error;
@@ -479,16 +479,10 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
 
 	if (block == NULL) {
 		struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
-		struct nlm_host	*host;
 
 		if (conf == NULL)
 			return nlm_granted;
-		/* Create host handle for callback */
-		host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
-		if (host == NULL) {
-			kfree(conf);
-			return nlm_lck_denied_nolocks;
-		}
+		nlm_get_host(host);
 		block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
 		if (block == NULL) {
 			kfree(conf);

fs/lockd/svcproc.c

@@ -128,7 +128,7 @@ nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_args *argp,
 		return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;
 
 	/* Now check for conflicting locks */
-	resp->status = cast_status(nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie));
+	resp->status = cast_status(nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock, &resp->cookie));
 	if (resp->status == nlm_drop_reply)
 		rc = rpc_drop_reply;
 	else

include/linux/lockd/lockd.h

@@ -203,7 +203,8 @@ __be32		  nlmsvc_lock(struct svc_rqst *, struct nlm_file *,
 					struct nlm_lock *, int, struct nlm_cookie *);
 __be32		  nlmsvc_unlock(struct nlm_file *, struct nlm_lock *);
 __be32		  nlmsvc_testlock(struct svc_rqst *, struct nlm_file *,
-			struct nlm_lock *, struct nlm_lock *, struct nlm_cookie *);
+			struct nlm_host *, struct nlm_lock *,
+			struct nlm_lock *, struct nlm_cookie *);
 __be32		  nlmsvc_cancel_blocked(struct nlm_file *, struct nlm_lock *);
 unsigned long	  nlmsvc_retry_blocked(void);
 void		  nlmsvc_traverse_blocks(struct nlm_host *, struct nlm_file *,