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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 2E6A5C433ED for ; Mon, 12 Apr 2021 10:21:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 005F361355 for ; Mon, 12 Apr 2021 10:21:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238520AbhDLKVv (ORCPT ); Mon, 12 Apr 2021 06:21:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238277AbhDLKVf (ORCPT ); Mon, 12 Apr 2021 06:21:35 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DACF5C06174A for ; Mon, 12 Apr 2021 03:21:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=suS2jhvKqcy3Sty7ScVC2iQKhuVPP5ZHHrLkCTVIKh0=; b=lmKqqzdiyZ0bAv8wrscI8iApb7 lUQRcv7lhrWH5XQZA2LmPwl/w6k/hx567Bj93okroeITBnnPIoNxSmHJNeaQ+Q/WMEyazFrFw1Uf1 UvWX0wDfANycyVxU9V0EBRI+vuITEfMIL/FPNGAm6vDYEu/pQdRDPVABJ9UfRwQT8xSqXmMJhWcNv 0R7N419wWxIIggkBDI+TerjZClhh9xXsjTJIcWTYSXLTIo0WVTJveG8hye6G7mp1lY3OyMz9At9M9 O4JLPMalE38epQjzAcD/7yYxs+rSGJCxDXkSUe3N9YqgC8ZsSuhPwY6syPvJXf5k0YRh1ccsdVtgj HtPKcFrw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lVtgj-006QVJ-Hf; Mon, 12 Apr 2021 10:21:01 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D136630026E; Mon, 12 Apr 2021 12:20:59 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id CD2D029D8B773; Mon, 12 Apr 2021 12:20:58 +0200 (CEST) Message-ID: <20210412102001.415407080@infradead.org> User-Agent: quilt/0.66 Date: Mon, 12 Apr 2021 12:14:27 +0200 From: Peter Zijlstra To: mingo@kernel.org, mgorman@suse.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, joshdon@google.com, valentin.schneider@arm.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, greg@kroah.com, linux@rasmusvillemoes.dk, Greg Kroah-Hartman Subject: [PATCH v2 6/9] debugfs: Implement debugfs_create_str() References: <20210412101421.609526370@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implement debugfs_create_str() to easily display names and such in debugfs. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Greg Kroah-Hartman --- fs/debugfs/file.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/debugfs.h | 17 ++++++++ 2 files changed, 108 insertions(+) --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -865,6 +865,97 @@ struct dentry *debugfs_create_bool(const } EXPORT_SYMBOL_GPL(debugfs_create_bool); +ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct dentry *dentry = F_DENTRY(file); + char *str, *copy = NULL; + int copy_len, len; + ssize_t ret; + + ret = debugfs_file_get(dentry); + if (unlikely(ret)) + return ret; + + str = *(char **)file->private_data; + len = strlen(str) + 1; + copy = kmalloc(len, GFP_KERNEL); + if (!copy) { + debugfs_file_put(dentry); + return -ENOMEM; + } + + copy_len = strscpy(copy, str, len); + debugfs_file_put(dentry); + if (copy_len < 0) { + kfree(copy); + return copy_len; + } + + copy[copy_len] = '\n'; + + ret = simple_read_from_buffer(user_buf, count, ppos, copy, copy_len); + kfree(copy); + + return ret; +} + +static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + /* This is really only for read-only strings */ + return -EINVAL; +} + +static const struct file_operations fops_str = { + .read = debugfs_read_file_str, + .write = debugfs_write_file_str, + .open = simple_open, + .llseek = default_llseek, +}; + +static const struct file_operations fops_str_ro = { + .read = debugfs_read_file_str, + .open = simple_open, + .llseek = default_llseek, +}; + +static const struct file_operations fops_str_wo = { + .write = debugfs_write_file_str, + .open = simple_open, + .llseek = default_llseek, +}; + +/** + * debugfs_create_str - create a debugfs file that is used to read and write a string value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be + * returned. + * + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will + * be returned. + */ +void debugfs_create_str(const char *name, umode_t mode, + struct dentry *parent, char **value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str, + &fops_str_ro, &fops_str_wo); +} + static ssize_t read_file_blob(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -128,6 +128,8 @@ void debugfs_create_atomic_t(const char struct dentry *parent, atomic_t *value); struct dentry *debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent, bool *value); +void debugfs_create_str(const char *name, umode_t mode, + struct dentry *parent, char **value); struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, @@ -156,6 +158,9 @@ ssize_t debugfs_read_file_bool(struct fi ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos); +ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos); + #else #include @@ -297,6 +302,11 @@ static inline struct dentry *debugfs_cre return ERR_PTR(-ENODEV); } +static inline void debugfs_create_str(const char *name, umode_t mode, + struct dentry *parent, + char **value) +{ } + static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob) @@ -347,6 +357,13 @@ static inline ssize_t debugfs_write_file { return -ENODEV; } + +static inline ssize_t debugfs_read_file_str(struct file *file, + char __user *user_buf, + size_t count, loff_t *ppos) +{ + return -ENODEV; +} #endif