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[23.128.96.18]) by mx.google.com with ESMTP id bm16si6282977edb.317.2021.09.23.08.26.51; Thu, 23 Sep 2021 08:27:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=jUfFyfM+; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241937AbhIWP0a (ORCPT + 99 others); Thu, 23 Sep 2021 11:26:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:60726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233143AbhIWP00 (ORCPT ); Thu, 23 Sep 2021 11:26:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7626960EE5; Thu, 23 Sep 2021 15:24:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632410694; bh=f+5asWyNTWseSfBfZnx/nBGPKc4I/06OBpr0rbMbwaU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=jUfFyfM+uoB0k7AsO0dZfeYv85TOxpDWqpfBYh++KbegIwOPm8CJExRXrKO95vrRm Tq2dyxwlJsAR+76gAH2SUd/1gSuy1ka0KjEGmjsjMkKV5eVDC4R7k+CbJHHmvmfpzU N5k3kpZTGi80XV2mhjqMPBxP1eE21SsVj3K4hLflZq+RBeGdJZIBBUGbnBn8Bfw9L8 Sem7xnCrVcYvTGVoiEeo6jfwyuBqmvOYSfitWzRdwj9+XLuALKePCA7ZoR3I6iMffS oXWGGHgrTlc/RmNZ25m4OHSixIFJFrUSFBRX0Sd4EtowOwnHJvOVIPogcL81OqmRfy lKDABhlJXiVfQ== Date: Thu, 23 Sep 2021 08:24:53 -0700 From: Jakub Kicinski To: Yajun Deng Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] net: socket: integrate sockfd_lookup() and sockfd_lookup_light() Message-ID: <20210923082453.42096cc7@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210922063106.4272-1-yajun.deng@linux.dev> References: <20210922063106.4272-1-yajun.deng@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 22 Sep 2021 14:31:06 +0800 Yajun Deng wrote: > As commit 6cb153cab92a("[NET]: use fget_light() in net/socket.c") said, > sockfd_lookup_light() is lower load than sockfd_lookup(). So we can > remove sockfd_lookup() but keep the name. As the same time, move flags > to sockfd_put(). You just assume that each caller of sockfd_lookup() already meets the criteria under which sockfd_lookup_light() can be used? Am I reading this right? Please extend the commit message clearly walking us thru why this is safe now (and perhaps why it wasn't in the past). > static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer, > size_t size) > @@ -1680,9 +1659,9 @@ int __sys_bind(int fd, struct sockaddr __user *umyaddr, int addrlen) > { > struct socket *sock; > struct sockaddr_storage address; > - int err, fput_needed; > + int err; > > - sock = sockfd_lookup_light(fd, &err, &fput_needed); > + sock = sockfd_lookup(fd, &err); > if (sock) { > err = move_addr_to_kernel(umyaddr, addrlen, &address); > if (!err) { > @@ -1694,7 +1673,7 @@ int __sys_bind(int fd, struct sockaddr __user *umyaddr, int addrlen) > (struct sockaddr *) > &address, addrlen); > } > - fput_light(sock->file, fput_needed); > + sockfd_put(sock); And we just replace fput_light() with fput() even tho the reference was taken with fdget()? fdget() == __fget_light(). Maybe you missed fget() vs fdget()? All these changes do not immediately strike me as correct. > } > return err; > }