net/socket: convert sock_map_fd() to FD_ADD()

Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-30-b6efa1706cfd@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

net/socket.c

@@ -503,21 +503,12 @@ EXPORT_SYMBOL(sock_alloc_file);
 
 static int sock_map_fd(struct socket *sock, int flags)
 {
-	struct file *newfile;
-	int fd = get_unused_fd_flags(flags);
-	if (unlikely(fd < 0)) {
-		sock_release(sock);
-		return fd;
-	}
+	int fd;
 
-	newfile = sock_alloc_file(sock, flags, NULL);
-	if (!IS_ERR(newfile)) {
-		fd_install(fd, newfile);
-		return fd;
-	}
-
-	put_unused_fd(fd);
-	return PTR_ERR(newfile);
+	fd = FD_ADD(flags, sock_alloc_file(sock, flags, NULL));
+	if (fd < 0)
+		sock_release(sock);
+	return fd;
 }
 
 /**