From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Tao Xu <tao3.xu@intel.com>,
jingqi.liu@intel.com, Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
H Peter Anvin <hpa@zytor.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ashok Raj <ashok.raj@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v2 1/3] x86/cpufeatures: Enumerate user wait instructions
Date: Thu, 21 Feb 2019 10:22:13 +0100 [thread overview]
Message-ID: <20190221092213.GA32477@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CALCETrWCJAzRj7BUBX=O2qdHXucNWz=z0uEQ5asskTbw8CGW5w@mail.gmail.com>
On Wed, Feb 20, 2019 at 10:37:27PM -0800, Andy Lutomirski wrote:
> On Wed, Feb 20, 2019 at 7:44 PM Tao Xu <tao3.xu@intel.com> wrote:
> > +static ssize_t umwait_enable_c0_2_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + return sprintf(buf, "%d\n", umwait_enable_c0_2);
>
> I realize that it's traditional to totally ignore races in sysfs and
> such, but it's a bad tradition. Please either READ_ONCE it with a
> comment or take the mutex.
Note that when using READ_ONCE(), the other side must use WRITE_ONCE().
Mixed usage is not valid.
next prev parent reply other threads:[~2019-02-21 9:22 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 21:18 [PATCH v2 0/3] x86/umwait: Enable user wait instructions Fenghua Yu
2019-01-16 21:18 ` [PATCH v2 1/3] x86/cpufeatures: Enumerate " Fenghua Yu
2019-01-16 21:18 ` [PATCH v2 2/3] x86/umwait: Setup umwait C0.2 state Fenghua Yu
2019-01-16 23:51 ` Andy Lutomirski
2019-01-16 21:18 ` [PATCH v2 3/3] x86/umwait: Control umwait maximum time Fenghua Yu
2019-01-17 0:00 ` Andy Lutomirski
2019-01-17 0:07 ` Fenghua Yu
2019-01-17 0:30 ` Andy Lutomirski
2019-01-17 2:06 ` Fenghua Yu
2019-01-20 19:12 ` Andrew Cooper
2019-01-20 21:40 ` Andy Lutomirski
2019-02-08 18:51 ` Yu, Fenghua
2019-01-16 21:18 ` [PATCH v2 0/3] x86/umwait: Enable user wait instructions Fenghua Yu
2019-01-16 21:18 ` [PATCH v2 1/3] x86/cpufeatures: Enumerate " Fenghua Yu
2019-02-21 6:37 ` Andy Lutomirski
2019-02-21 9:22 ` Peter Zijlstra [this message]
2019-02-21 19:24 ` Fenghua Yu
2019-02-21 22:57 ` Yu, Fenghua
2019-02-24 19:45 ` Andy Lutomirski
2019-02-26 19:53 ` Fenghua Yu
2019-02-22 2:09 ` Tao Xu
2019-02-26 20:41 ` Fenghua Yu
2019-01-16 21:18 ` [PATCH v2 2/3] x86/umwait: Setup umwait C0.2 state Fenghua Yu
2019-01-16 21:18 ` [PATCH v2 3/3] x86/umwait: Control umwait maximum time Fenghua Yu
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