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Message-ID: <311a6ac0-98c0-708f-1866-fcfc6c5e90f2@kernel.org>
Date:   Wed, 20 Jul 2022 17:20:14 +0200
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Subject: Re: [PATCH V6 01/16] rv: Add Runtime Verification (RV) interface
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To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Jonathan Corbet <corbet@lwn.net>,
        Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Marco Elver <elver@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Gabriele Paoloni <gpaoloni@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Clark Williams <williams@redhat.com>,
        Tao Zhou <tao.zhou@linux.dev>,
        Randy Dunlap <rdunlap@infradead.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-trace-devel@vger.kernel.org
References: <cover.1658244826.git.bristot@kernel.org>
 <69bb4c369b4f6f12014eb9ca3c28b74e4378c007.1658244826.git.bristot@kernel.org>
 <20220720104718.59148968@gandalf.local.home>
From:   Daniel Bristot de Oliveira <bristot@kernel.org>
In-Reply-To: <20220720104718.59148968@gandalf.local.home>
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On 7/20/22 16:47, Steven Rostedt wrote:
> On Tue, 19 Jul 2022 19:27:06 +0200
> Daniel Bristot de Oliveira <bristot@kernel.org> wrote:
> 
>> +/*
>> + * Interface to read the enable/disable status of a monitor.
>> + */
>> +static ssize_t monitor_desc_read_data(struct file *filp, char __user *user_buf, size_t count,
>> +				      loff_t *ppos)
>> +{
>> +	struct rv_monitor_def *mdef = filp->private_data;
>> +	char buff[256];
>> +
>> +	memset(buff, 0, sizeof(buff));
>> +
>> +	mutex_lock(&rv_interface_lock);
>> +	snprintf(buff, sizeof(buff), "%s\n", mdef->monitor->description);
>> +	mutex_unlock(&rv_interface_lock);
> 
> What exactly is the mutex protecting here?

I placed it around all access on read/write in the interface,
but indeed, it is not needed here (static data). It is in a file inside
the monitor's directory... so the directory is there, and the
module is there as well.

-- Daniel