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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 00EBCC433F5 for ; Mon, 20 Sep 2021 17:20:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9FE363286 for ; Mon, 20 Sep 2021 17:20:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349200AbhITRWV (ORCPT ); Mon, 20 Sep 2021 13:22:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:45924 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346525AbhITRUI (ORCPT ); Mon, 20 Sep 2021 13:20:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 922E86135A; Mon, 20 Sep 2021 17:00:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632157227; bh=DuBStQt5mVWOrW3wxvNKE+kyAnvAPfObhqFJftQAAsg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jxEULqWK2ArkMjD4OTjirO/pEGs7NkrW9oH1UB638JFjEIz/8lASMpO3PyQyFQQ4S u1pOGwcHPIOblmqnqSc5LG8CLV/3taFXLXfOtZaFpJ+1toHFlPPI+T5bNUZyxPEX9q Dwlc+QOSzTXPb2sshVtrFGHm++olTM+OQKru1kiI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Shevchenko , Andrew Morton , Cezary Rojewski , Linus Torvalds Subject: [PATCH 4.14 104/217] include/linux/list.h: add a macro to test if entry is pointing to the head Date: Mon, 20 Sep 2021 18:42:05 +0200 Message-Id: <20210920163928.162261373@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163924.591371269@linuxfoundation.org> References: <20210920163924.591371269@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Shevchenko commit e130816164e244b692921de49771eeb28205152d upstream. Add a macro to test if entry is pointing to the head of the list which is useful in cases like: list_for_each_entry(pos, &head, member) { if (cond) break; } if (list_entry_is_head(pos, &head, member)) return -ERRNO; that allows to avoid additional variable to be added to track if loop has not been stopped in the middle. While here, convert list_for_each_entry*() family of macros to use a new one. Signed-off-by: Andy Shevchenko Signed-off-by: Andrew Morton Reviewed-by: Cezary Rojewski Link: https://lkml.kernel.org/r/20200929134342.51489-1-andriy.shevchenko@linux.intel.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/list.h | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) --- a/include/linux/list.h +++ b/include/linux/list.h @@ -485,6 +485,15 @@ static inline void list_splice_tail_init pos = n, n = pos->prev) /** + * list_entry_is_head - test if the entry points to the head of the list + * @pos: the type * to cursor + * @head: the head for your list. + * @member: the name of the list_head within the struct. + */ +#define list_entry_is_head(pos, head, member) \ + (&pos->member == (head)) + +/** * list_for_each_entry - iterate over list of given type * @pos: the type * to use as a loop cursor. * @head: the head for your list. @@ -492,7 +501,7 @@ static inline void list_splice_tail_init */ #define list_for_each_entry(pos, head, member) \ for (pos = list_first_entry(head, typeof(*pos), member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member)) /** @@ -503,7 +512,7 @@ static inline void list_splice_tail_init */ #define list_for_each_entry_reverse(pos, head, member) \ for (pos = list_last_entry(head, typeof(*pos), member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_prev_entry(pos, member)) /** @@ -528,7 +537,7 @@ static inline void list_splice_tail_init */ #define list_for_each_entry_continue(pos, head, member) \ for (pos = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member)) /** @@ -542,7 +551,7 @@ static inline void list_splice_tail_init */ #define list_for_each_entry_continue_reverse(pos, head, member) \ for (pos = list_prev_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = list_prev_entry(pos, member)) /** @@ -554,7 +563,7 @@ static inline void list_splice_tail_init * Iterate over list of given type, continuing from current position. */ #define list_for_each_entry_from(pos, head, member) \ - for (; &pos->member != (head); \ + for (; !list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member)) /** @@ -567,7 +576,7 @@ static inline void list_splice_tail_init * Iterate backwards over list of given type, continuing from current position. */ #define list_for_each_entry_from_reverse(pos, head, member) \ - for (; &pos->member != (head); \ + for (; !list_entry_is_head(pos, head, member); \ pos = list_prev_entry(pos, member)) /** @@ -580,7 +589,7 @@ static inline void list_splice_tail_init #define list_for_each_entry_safe(pos, n, head, member) \ for (pos = list_first_entry(head, typeof(*pos), member), \ n = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_next_entry(n, member)) /** @@ -596,7 +605,7 @@ static inline void list_splice_tail_init #define list_for_each_entry_safe_continue(pos, n, head, member) \ for (pos = list_next_entry(pos, member), \ n = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_next_entry(n, member)) /** @@ -611,7 +620,7 @@ static inline void list_splice_tail_init */ #define list_for_each_entry_safe_from(pos, n, head, member) \ for (n = list_next_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_next_entry(n, member)) /** @@ -627,7 +636,7 @@ static inline void list_splice_tail_init #define list_for_each_entry_safe_reverse(pos, n, head, member) \ for (pos = list_last_entry(head, typeof(*pos), member), \ n = list_prev_entry(pos, member); \ - &pos->member != (head); \ + !list_entry_is_head(pos, head, member); \ pos = n, n = list_prev_entry(n, member)) /**