clean unix_bind() up a bit

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

net/unix/af_unix.c

@@ -814,6 +814,34 @@ static struct sock *unix_find_other(struct net *net,
 	return NULL;
 }
 
+static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
+{
+	struct dentry *dentry;
+	struct path path;
+	int err = 0;
+	/*
+	 * Get the parent directory, calculate the hash for last
+	 * component.
+	 */
+	dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
+	err = PTR_ERR(dentry);
+	if (IS_ERR(dentry))
+		return err;
+
+	/*
+	 * All right, let's create it.
+	 */
+	err = security_path_mknod(&path, dentry, mode, 0);
+	if (!err) {
+		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
+		if (!err) {
+			res->mnt = mntget(path.mnt);
+			res->dentry = dget(dentry);
+		}
+	}
+	done_path_create(&path, dentry);
+	return err;
+}
 
 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 {
@@ -822,8 +850,6 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	struct unix_sock *u = unix_sk(sk);
 	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
 	char *sun_path = sunaddr->sun_path;
-	struct dentry *dentry = NULL;
-	struct path path;
 	int err;
 	unsigned int hash;
 	struct unix_address *addr;
@@ -860,40 +886,23 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	atomic_set(&addr->refcnt, 1);
 
 	if (sun_path[0]) {
-		umode_t mode;
-		err = 0;
-		/*
-		 * Get the parent directory, calculate the hash for last
-		 * component.
-		 */
-		dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
-		err = PTR_ERR(dentry);
-		if (IS_ERR(dentry))
-			goto out_mknod_parent;
-
-		/*
-		 * All right, let's create it.
-		 */
-		mode = S_IFSOCK |
+		struct path path;
+		umode_t mode = S_IFSOCK |
 		       (SOCK_INODE(sock)->i_mode & ~current_umask());
-		err = security_path_mknod(&path, dentry, mode, 0);
-		if (err)
-			goto out_mknod_drop_write;
-		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
-out_mknod_drop_write:
-		if (err)
-			goto out_mknod_dput;
-		mntget(path.mnt);
-		dget(dentry);
-		done_path_create(&path, dentry);
-		path.dentry = dentry;
-
-		addr->hash = UNIX_HASH_SIZE;
+		err = unix_mknod(sun_path, mode, &path);
+		if (err) {
+			if (err == -EEXIST)
+				err = -EADDRINUSE;
+			unix_release_addr(addr);
+			goto out_up;
 		}
-
+		addr->hash = UNIX_HASH_SIZE;
+		hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1);
+		spin_lock(&unix_table_lock);
+		u->path = path;
+		list = &unix_socket_table[hash];
+	} else {
 		spin_lock(&unix_table_lock);
-
-	if (!sun_path[0]) {
 		err = -EADDRINUSE;
 		if (__unix_find_socket_byname(net, sunaddr, addr_len,
 					      sk->sk_type, hash)) {
@@ -902,9 +911,6 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 		}
 
 		list = &unix_socket_table[addr->hash];
-	} else {
-		list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
-		u->path = path;
 	}
 
 	err = 0;
@@ -918,14 +924,6 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	mutex_unlock(&u->readlock);
 out:
 	return err;
-
-out_mknod_dput:
-	done_path_create(&path, dentry);
-out_mknod_parent:
-	if (err == -EEXIST)
-		err = -EADDRINUSE;
-	unix_release_addr(addr);
-	goto out_up;
 }
 
 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)