From patchwork Fri Dec 20 16:06:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13916965 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2225F249EB; Fri, 20 Dec 2024 16:05:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734710740; cv=none; b=ZbOPSp91nOsjq8IpGbxftUOjbUoC727j4Hr2Hj4va0b/X4GGkXp7KCOe1TmCMgMyMN1mOcoj4aFMSPo31VdV4InRmBnABQ9gDZmdFG29/LbwFIsM6CfBQZ+o2nXV5cd9gOhaP2CcBHnsPv7HGUqINa4aEEN47PqHTwBl4ULnAnw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734710740; c=relaxed/simple; bh=alqQ1w07sUqMnAtW5s7FXfLsCCFItKmt7jp9g0bK2fM=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=Ol0Tx+ZgatmKhekE5sPTbQYSPYUR+Cg1y6fJtoKCmsKIKuaC2qwmxS9qRKKVFjod/sBtxLMThE4OaqMsOYYWG/NPnC+zjj9/LATEudZRaC7qpRtnKAStqbGTUopqSAKH4jokxO4j/ZZd6XZ/TI7HX8J/Iuw9Ppxrq2PY4PzfdNk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05383C4CECD; Fri, 20 Dec 2024 16:05:38 +0000 (UTC) Date: Fri, 20 Dec 2024 11:06:21 -0500 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Mathieu Desnoyers , Peter Zijlstra Subject: [PATCH v2] tracing: Switch trace_events_trigger.c code over to use guard() Message-ID: <20241220110621.639d3bc8@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Steven Rostedt There are a few functions in trace_events_trigger.c that have "goto out" or equivalent on error in order to release locks that were taken. This can be error prone or just simply make the code more complex. Switch every location that ends with unlocking a mutex on error over to using the guard(mutex)() infrastructure to let the compiler worry about releasing locks. This makes the code easier to read and understand. Also use __free() for free a temporary buffer in event_trigger_regex_write(). Signed-off-by: Steven Rostedt (Google) --- Changes since v1: https://lore.kernel.org/all/20241219201345.860391310@goodmis.org/ - Removed the no_free_ptr() around buf on IS_ERR(buf) being true as the __free() can handle that case. kernel/trace/trace_events_trigger.c | 67 ++++++++++------------------- 1 file changed, 23 insertions(+), 44 deletions(-) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index a5e3d6acf1e1..d45448947094 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -211,12 +211,10 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file) if (ret) return ret; - mutex_lock(&event_mutex); + guard(mutex)(&event_mutex); - if (unlikely(!event_file_file(file))) { - mutex_unlock(&event_mutex); + if (unlikely(!event_file_file(file))) return -ENODEV; - } if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { @@ -239,8 +237,6 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file) } } - mutex_unlock(&event_mutex); - return ret; } @@ -248,7 +244,6 @@ int trigger_process_regex(struct trace_event_file *file, char *buff) { char *command, *next; struct event_command *p; - int ret = -EINVAL; next = buff = skip_spaces(buff); command = strsep(&next, ": \t"); @@ -259,17 +254,14 @@ int trigger_process_regex(struct trace_event_file *file, char *buff) } command = (command[0] != '!') ? command : command + 1; - mutex_lock(&trigger_cmd_mutex); + guard(mutex)(&trigger_cmd_mutex); + list_for_each_entry(p, &trigger_commands, list) { - if (strcmp(p->name, command) == 0) { - ret = p->parse(p, file, buff, command, next); - goto out_unlock; - } + if (strcmp(p->name, command) == 0) + return p->parse(p, file, buff, command, next); } - out_unlock: - mutex_unlock(&trigger_cmd_mutex); - return ret; + return -EINVAL; } static ssize_t event_trigger_regex_write(struct file *file, @@ -278,7 +270,7 @@ static ssize_t event_trigger_regex_write(struct file *file, { struct trace_event_file *event_file; ssize_t ret; - char *buf; + char *buf __free(kfree) = NULL; if (!cnt) return 0; @@ -292,24 +284,18 @@ static ssize_t event_trigger_regex_write(struct file *file, strim(buf); - mutex_lock(&event_mutex); + guard(mutex)(&event_mutex); + event_file = event_file_file(file); - if (unlikely(!event_file)) { - mutex_unlock(&event_mutex); - kfree(buf); + if (unlikely(!event_file)) return -ENODEV; - } - ret = trigger_process_regex(event_file, buf); - mutex_unlock(&event_mutex); - kfree(buf); + ret = trigger_process_regex(event_file, buf); if (ret < 0) - goto out; + return ret; *ppos += cnt; - ret = cnt; - out: - return ret; + return cnt; } static int event_trigger_regex_release(struct inode *inode, struct file *file) @@ -359,20 +345,16 @@ const struct file_operations event_trigger_fops = { __init int register_event_command(struct event_command *cmd) { struct event_command *p; - int ret = 0; - mutex_lock(&trigger_cmd_mutex); + guard(mutex)(&trigger_cmd_mutex); + list_for_each_entry(p, &trigger_commands, list) { - if (strcmp(cmd->name, p->name) == 0) { - ret = -EBUSY; - goto out_unlock; - } + if (strcmp(cmd->name, p->name) == 0) + return -EBUSY; } list_add(&cmd->list, &trigger_commands); - out_unlock: - mutex_unlock(&trigger_cmd_mutex); - return ret; + return 0; } /* @@ -382,20 +364,17 @@ __init int register_event_command(struct event_command *cmd) __init int unregister_event_command(struct event_command *cmd) { struct event_command *p, *n; - int ret = -ENODEV; - mutex_lock(&trigger_cmd_mutex); + guard(mutex)(&trigger_cmd_mutex); + list_for_each_entry_safe(p, n, &trigger_commands, list) { if (strcmp(cmd->name, p->name) == 0) { - ret = 0; list_del_init(&p->list); - goto out_unlock; + return 0; } } - out_unlock: - mutex_unlock(&trigger_cmd_mutex); - return ret; + return -ENODEV; } /**