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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 10D49C004E6 for ; Thu, 27 Jun 2019 20:49:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E05882133F for ; Thu, 27 Jun 2019 20:49:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="3DCpydkR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726476AbfF0UtQ (ORCPT ); Thu, 27 Jun 2019 16:49:16 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:35796 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726384AbfF0UtQ (ORCPT ); Thu, 27 Jun 2019 16:49:16 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5RKmlJt138548; Thu, 27 Jun 2019 20:48:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=usEbhKUubJqAyKMe84VK/QUHzNxZ7h5CLD/lV2JoXTY=; b=3DCpydkRs2k0EE6F6PNkDOMbVB9Qk27b9PXxp4vGhFxqa4J7vzxgEgfBjgJNPwBTjkB7 d6ArRnjj8RxSOQiVHgbxYNcn7MEx8aXbbNRG2ZYqku5ifRCyrkKjyHaMRkirY14HPMBs PKn5DDYiSsZL0Ah/KIlxrVZuprWMsBn46zeZbwhTYsU5HHMZRGVMeIOM6CgLY8w2QWsA VaSEsRjgve8EXIVBJW+O/iomYYbsRSGwrdwX6UZzW1/IQfgzymBxQFCgeAUce8a9dIsc qUuZhTapslmdtC8pNOPy9dVRKO9smU5E4bjEX3BoUxqsGHLMe5ZuQsbDTEZcwQqlm6EV yQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 2t9cyqtb5u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 27 Jun 2019 20:48:46 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5RKlh2X056729; Thu, 27 Jun 2019 20:48:44 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2t9p6vj1v8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 27 Jun 2019 20:48:44 +0000 Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x5RKmhVc024270; Thu, 27 Jun 2019 20:48:43 GMT Received: from localhost (/10.145.179.81) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 27 Jun 2019 13:48:43 -0700 Date: Thu, 27 Jun 2019 13:48:42 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Damien Le Moal , Andreas Gruenbacher , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/13] list.h: add list_pop and list_pop_entry helpers Message-ID: <20190627204842.GR5171@magnolia> References: <20190627104836.25446-1-hch@lst.de> <20190627104836.25446-2-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190627104836.25446-2-hch@lst.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9301 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906270239 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9301 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906270240 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Jun 27, 2019 at 12:48:24PM +0200, Christoph Hellwig wrote: > We have a very common pattern where we want to delete the first entry > from a list and return it as the properly typed container structure. > > Add two helpers to implement this behavior. > > Signed-off-by: Christoph Hellwig LGTM, Reviewed-by: Darrick J. Wong --D > --- > include/linux/list.h | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/include/linux/list.h b/include/linux/list.h > index e951228db4b2..ba6e27d2235a 100644 > --- a/include/linux/list.h > +++ b/include/linux/list.h > @@ -500,6 +500,39 @@ static inline void list_splice_tail_init(struct list_head *list, > pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ > }) > > +/** > + * list_pop - delete the first entry from a list and return it > + * @list: the list to take the element from. > + * > + * Return the list entry after @list. If @list is empty return NULL. > + */ > +static inline struct list_head *list_pop(struct list_head *list) > +{ > + struct list_head *pos = READ_ONCE(list->next); > + > + if (pos == list) > + return NULL; > + list_del(pos); > + return pos; > +} > + > +/** > + * list_pop_entry - delete the first entry from a list and return the > + * containing structure > + * @list: the list to take the element from. > + * @type: the type of the struct this is embedded in. > + * @member: the name of the list_head within the struct. > + * > + * Return the containing structure for the list entry after @list. If @list > + * is empty return NULL. > + */ > +#define list_pop_entry(list, type, member) \ > +({ \ > + struct list_head *pos__ = list_pop(list); \ > + \ > + pos__ ? list_entry(pos__, type, member) : NULL; \ > +}) > + > /** > * list_next_entry - get the next element in list > * @pos: the type * to cursor > -- > 2.20.1 >