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=-16.8 required=3.0 tests=BAYES_00, 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 AD92DC4708D for ; Fri, 28 May 2021 11:40:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B6E1613D1 for ; Fri, 28 May 2021 11:40:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235523AbhE1Llw (ORCPT ); Fri, 28 May 2021 07:41:52 -0400 Received: from foss.arm.com ([217.140.110.172]:39654 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233583AbhE1Llu (ORCPT ); Fri, 28 May 2021 07:41:50 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0A0241516; Fri, 28 May 2021 04:40:16 -0700 (PDT) Received: from entos-ampere-02.shanghai.arm.com (entos-ampere-02.shanghai.arm.com [10.169.214.103]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CA0963F73B; Fri, 28 May 2021 04:40:09 -0700 (PDT) From: Jia He To: Linus Torvalds , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Jonathan Corbet , Alexander Viro , Luca Coelho , Kalle Valo , "David S. Miller" , Jakub Kicinski , Heiko Carstens , Vasily Gorbik Cc: Christian Borntraeger , Johannes Berg , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, Jia He Subject: [PATCH RFCv2 1/3] fs: introduce helper d_path_fast() Date: Fri, 28 May 2021 19:39:49 +0800 Message-Id: <20210528113951.6225-2-justin.he@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210528113951.6225-1-justin.he@arm.com> References: <20210528113951.6225-1-justin.he@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org This helper is similar to d_path except that it doesn't take any seqlock/spinlock. It is typical for debugging purpose. Signed-off-by: Jia He --- fs/d_path.c | 21 +++++++++++++++++++++ include/linux/dcache.h | 1 + 2 files changed, 22 insertions(+) diff --git a/fs/d_path.c b/fs/d_path.c index 23a53f7b5c71..f9df68d62786 100644 --- a/fs/d_path.c +++ b/fs/d_path.c @@ -263,6 +263,27 @@ char *d_path(const struct path *path, char *buf, int buflen) } EXPORT_SYMBOL(d_path); +/** + * d_path_fast - fast return the full path of a dentry without taking + * any seqlock/spinlock. This helper is typical for debugging purpose + */ +char *d_path_fast(const struct path *path, char *buf, int buflen) +{ + struct path root; + struct mount *mnt = real_mount(path->mnt); + DECLARE_BUFFER(b, buf, buflen); + + rcu_read_lock(); + get_fs_root_rcu(current->fs, &root); + + prepend(&b, "", 1); + __prepend_path(path->dentry, mnt, &root, &b); + rcu_read_unlock(); + + return extract_string(&b); +} +EXPORT_SYMBOL(d_path_fast); + /* * Helper function for dentry_operations.d_dname() members */ diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 9e23d33bb6f1..c4483fc887a5 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -301,6 +301,7 @@ char *dynamic_dname(struct dentry *, char *, int, const char *, ...); extern char *__d_path(const struct path *, const struct path *, char *, int); extern char *d_absolute_path(const struct path *, char *, int); extern char *d_path(const struct path *, char *, int); +extern char *d_path_fast(const struct path *, char *, int); extern char *dentry_path_raw(const struct dentry *, char *, int); extern char *dentry_path(const struct dentry *, char *, int); -- 2.17.1