From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9C1DC3A5A4 for ; Sun, 1 Sep 2019 07:11:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE31B233A2 for ; Sun, 1 Sep 2019 07:11:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728777AbfIAHLl (ORCPT ); Sun, 1 Sep 2019 03:11:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40498 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728679AbfIAHLl (ORCPT ); Sun, 1 Sep 2019 03:11:41 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ABFFB189DAD1; Sun, 1 Sep 2019 07:11:40 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-255.rdu2.redhat.com [10.10.120.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8640E5D9D6; Sun, 1 Sep 2019 07:11:39 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20190901065603.432-1-hdanton@sina.com> References: <20190901065603.432-1-hdanton@sina.com> <156708405310.26102.7954021163316252673.stgit@warthog.procyon.org.uk> To: Hillf Danton Cc: dhowells@redhat.com, netdev@vger.kernel.org, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net 7/7] rxrpc: Use skb_unshare() rather than skb_cow_data() MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <14326.1567321898.1@warthog.procyon.org.uk> Date: Sun, 01 Sep 2019 08:11:38 +0100 Message-ID: <14327.1567321898@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.63]); Sun, 01 Sep 2019 07:11:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hillf Danton wrote: > > + /* Unshare the packet so that it can be modified for in-place > > + * decryption. > > + */ > > + if (sp->hdr.securityIndex != 0) { > > + struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC); > > + if (!nskb) { > > + rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem); > > + goto out; > > + } > > + > > + if (nskb != skb) { > > + rxrpc_eaten_skb(skb, rxrpc_skb_received); > > + rxrpc_new_skb(skb, rxrpc_skb_unshared); > > + skb = nskb; > > + sp = rxrpc_skb(skb); > > + } > > + } > > Unsharing skb makes it perilous to take a peep at it afterwards. Ah, good point. rxrpc_new_skb() should be after the assignment. David