{"id":811328,"url":"http://patchwork.ozlabs.org/api/1.2/patches/811328/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/patch/60c8906b751d4915be456009c220516e-mfwitten@gmail.com/","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/1.2/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<60c8906b751d4915be456009c220516e-mfwitten@gmail.com>","list_archive_url":null,"date":"2017-09-08T05:06:30","name":"[3/3] net: skb_queue_purge(): lock/unlock the list only once","commit_ref":null,"pull_url":null,"state":"deferred","archived":true,"hash":"9580c82a46646a60477c2d62cc35e7599af2e293","submitter":{"id":7859,"url":"http://patchwork.ozlabs.org/api/1.2/people/7859/?format=json","name":"Michael Witten","email":"mfwitten@gmail.com"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/1.2/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/60c8906b751d4915be456009c220516e-mfwitten@gmail.com/mbox/","series":[{"id":2106,"url":"http://patchwork.ozlabs.org/api/1.2/series/2106/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/list/?series=2106","date":"2017-09-08T05:05:37","name":"[1/3] net: __sock_cmsg_send(): Remove unused parameter `msg'","version":1,"mbox":"http://patchwork.ozlabs.org/series/2106/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/811328/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/811328/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","ozlabs.org; dkim=pass (2048-bit key;\n\tunprotected) header.d=gmail.com header.i=@gmail.com\n\theader.b=\"rqvFK14w\"; dkim-atps=neutral"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xpRZQ6GZ7z9sBZ\n\tfor ;\n\tFri, 8 Sep 2017 16:03:10 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1754351AbdIHGC7 (ORCPT );\n\tFri, 8 Sep 2017 02:02:59 -0400","from mail-pg0-f65.google.com ([74.125.83.65]:35790 \"EHLO\n\tmail-pg0-f65.google.com\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1753126AbdIHGC5 (ORCPT\n\t); Fri, 8 Sep 2017 02:02:57 -0400","by mail-pg0-f65.google.com with SMTP id q68so910957pgq.2;\n\tThu, 07 Sep 2017 23:02:57 -0700 (PDT)","from gmail.com ([65.19.167.131]) by smtp.gmail.com with ESMTPSA id\n\tv31sm1592458pgn.43.2017.09.07.23.02.56\n\t(version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256);\n\tThu, 07 Sep 2017 23:02:56 -0700 (PDT)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=gmail.com; s=20161025;\n\th=subject:date:from:to:cc:message-id:in-reply-to:references;\n\tbh=wRRANe9PVnKI4EYakI0+6FyWEWs6ONglqKruoWLZ2Cw=;\n\tb=rqvFK14wQycZwHVLCt6a5/5zXddEAyvqaUukz+Lt2rS5f9ZJjzOZ5lb8ZeUKQA4Kra\n\tchVIjqz8LKQSjRXYO4ssvY1wBm5b8jFU1PXUQDCmNj5gi3CtfTHGVjWKd9OFHcvXM12c\n\tdwHslSon4llHeimoF+t03F39Esu8HJrUiEsBcsoOe/aq7BtHxwO7TrCpWIjim4FQdtKb\n\tWndT2zpgXY602OerF462+3tt+5hwvXCCW6ROsrgEzvCljYBsSm+bEbPByXiHiRK3Nyf0\n\t5tYdTngZfIpr/NSz+HKZvfgvHTSQwo+fQwV3H6c3QJceJwfvaS3m8q4VjvnuSdT1JocV\n\t081g==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:subject:date:from:to:cc:message-id:in-reply-to\n\t:references;\n\tbh=wRRANe9PVnKI4EYakI0+6FyWEWs6ONglqKruoWLZ2Cw=;\n\tb=pkUParxYJzthmZjgT0PLxixTxW48fotU3Vq6/6gbmxjjVA4KuZ4kiXkm0vwZbllnX5\n\tuULeofjtdHaLt6Ir+NKp07t/Qzk7G29YRyf/w+6U1/Q/lA191yktP45mmhMMhKEmJNgo\n\tDnEq2WfZPydavYs4zVqYTR1tsGIThgW9BI+6r2cda3xgyrZGOg/1RUwXBegs/TFPjVGl\n\te9KCFQEkNucRQIpkSgx4dayNOE5S/7d/xwFMn/5idwtwvmX7YGdcopqzh/qQdFU5qFwJ\n\tPnhB1p86FBtRc9A+IsAuEEpRYrUs6x/nzJ7TpmwoUt3eR0JfthedIJcHklnYTiInjHHs\n\trM5A==","X-Gm-Message-State":"AHPjjUhv+aiO+L8Rp8pSCY8ozjuXLUitQNIe+2COo5HYWNbS+6qZ9+R2\n\t4q+y6aOJVp+Vag==","X-Google-Smtp-Source":"ADKCNb6hIAFrvaX2WYm1o3Oywk9FJcPBqhzq3vP21Wi0gabKGDcSGeimRN/hDE2TdJ7aMqoXVMaCRw==","X-Received":"by 10.84.224.206 with SMTP id k14mr2179545pln.317.1504850577271; \n\tThu, 07 Sep 2017 23:02:57 -0700 (PDT)","Subject":"[PATCH 3/3] net: skb_queue_purge(): lock/unlock the list only once","Date":"Fri, 08 Sep 2017 05:06:30 -0000","From":"Michael Witten ","To":"\"David S. Miller\" ,\n\tAlexey Kuznetsov ,\n\tHideaki YOSHIFUJI ","Cc":"netdev@vger.kernel.org, linux-kernel@vger.kernel.org","Message-ID":"<60c8906b751d4915be456009c220516e-mfwitten@gmail.com>","In-Reply-To":"<45aab5effc0c424a992646a97cf2ec14-mfwitten@gmail.com>","References":"<45aab5effc0c424a992646a97cf2ec14-mfwitten@gmail.com>","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"},"content":"Date: Thu, 7 Sep 2017 20:07:40 +0000\nWith this commit, the list's lock is locked/unlocked only once\nfor the duration of `skb_queue_purge()'.\n\nHitherto, the list's lock has been locked/unlocked every time\nan item is dequeued; this seems not only inefficient, but also\nincorrect, as the whole point of `skb_queue_purge()' is to clear\nthe list, presumably without giving anything else a chance to\nmanipulate the list in the interim.\n\nSigned-off-by: Michael Witten \n---\n net/core/skbuff.c | 6 +++++-\n 1 file changed, 5 insertions(+), 1 deletion(-)","diff":"diff --git a/net/core/skbuff.c b/net/core/skbuff.c\nindex 68065d7d383f..66c0731a2a5f 100644\n--- a/net/core/skbuff.c\n+++ b/net/core/skbuff.c\n@@ -2834,9 +2834,13 @@ EXPORT_SYMBOL(skb_dequeue_tail);\n */\n void skb_queue_purge(struct sk_buff_head *list)\n {\n+\tunsigned long flags;\n \tstruct sk_buff *skb;\n-\twhile ((skb = skb_dequeue(list)) != NULL)\n+\n+\tspin_lock_irqsave(&list->lock, flags);\n+\twhile ((skb = __skb_dequeue(list)) != NULL)\n \t\tkfree_skb(skb);\n+\tspin_unlock_irqrestore(&list->lock, flags);\n }\n EXPORT_SYMBOL(skb_queue_purge);\n \n","prefixes":["3/3"]}