From: Thomas Gleixner <tglx@linutronix.de>
To: "André Almeida" <andrealmeid@riseup.net>,
LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Adhemerval Zanella <adhemerval.zanella@linaro.org>,
Lukasz Majewski <lukma@denx.de>,
Florian Weimer <fweimer@redhat.com>,
Carlos O'Donell <carlos@redhat.com>,
"Michael Kerrisk \(man-pages\)" <mtk.manpages@gmail.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Ingo Molnar <mingo@kernel.org>,
Kurt Kanzenbach <kurt@linutronix.de>,
Darren Hart <dvhart@infradead.org>,
Andrei Vagin <avagin@gmail.com>,
kernel@collabora.com
Subject: Re: [patch 6/6] futex: Provide FUTEX_LOCK_PI2 to support clock selection
Date: Sat, 24 Apr 2021 00:36:48 +0200 [thread overview]
Message-ID: <87o8e4vda7.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <606120ab-ef46-fa87-5f2c-d480de9ed2c8@riseup.net>
André!
On Fri, Apr 23 2021 at 19:20, André Almeida wrote:
>> @@ -21,6 +21,7 @@
>> #define FUTEX_WAKE_BITSET 10
>> #define FUTEX_WAIT_REQUEUE_PI 11
>> #define FUTEX_CMP_REQUEUE_PI 12
>> +#define FUTEX_LOCK_PI2 13
>>
>> #define FUTEX_PRIVATE_FLAG 128
>> #define FUTEX_CLOCK_REALTIME 256
>
> To keep consistency with other operations, maybe add a
> FUTEX_LOCK_PI2_PRIVATE?
Good point! Missed that.
>> --- a/kernel/futex.c
>> +++ b/kernel/futex.c
>> @@ -3711,7 +3711,8 @@ long do_futex(u32 __user *uaddr, int op,
>>
>> if (op & FUTEX_CLOCK_REALTIME) {
>> flags |= FLAGS_CLOCKRT;
>> - if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI)
>> + if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
>> + cmd != FUTEX_LOCK_PI2)
>> return -ENOSYS;
>> }
>
> As FUTEX_LOCK_PI, FUTEX_LOCK_PI2 also requires FUTEX_CMPXCHG right?
> Then, add it here:
>
> switch (cmd) {
> case FUTEX_LOCK_PI:
> + case FUTEX_LOCK_PI2:
> case FUTEX_UNLOCK_PI:
> case FUTEX_TRYLOCK_PI:
> case FUTEX_WAIT_REQUEUE_PI:
> case FUTEX_CMP_REQUEUE_PI:
> if (!futex_cmpxchg_enabled)
> return -ENOSYS;
> }
Indeed. Forgot about that completely.
Thanks for spotting that!
tglx
next prev parent reply other threads:[~2021-04-23 22:36 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 19:44 [patch 0/6] futex: Bugfixes and FUTEX_LOCK_PI2 Thomas Gleixner
2021-04-22 19:44 ` [patch 1/6] Revert 337f13046ff0 ("futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op") Thomas Gleixner
2021-05-06 18:14 ` [tip: locking/urgent] " tip-bot2 for Thomas Gleixner
2021-04-22 19:44 ` [patch 2/6] futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI Thomas Gleixner
2021-05-06 18:14 ` [tip: locking/urgent] " tip-bot2 for Thomas Gleixner
2021-04-22 19:44 ` [patch 3/6] futex: Get rid of the val2 conditional dance Thomas Gleixner
2021-04-23 21:40 ` André Almeida
2021-04-23 22:34 ` Thomas Gleixner
2021-04-23 23:21 ` André Almeida
2021-05-06 18:20 ` [tip: locking/urgent] " tip-bot2 for Thomas Gleixner
2021-04-22 19:44 ` [patch 4/6] futex: Make syscall entry points less convoluted Thomas Gleixner
2021-05-06 18:20 ` [tip: locking/urgent] " tip-bot2 for Thomas Gleixner
2021-04-22 19:44 ` [patch 5/6] futex: Prepare futex_lock_pi() for runtime clock selection Thomas Gleixner
2021-04-23 9:34 ` Lukasz Majewski
2021-04-23 10:08 ` Thomas Gleixner
2021-06-23 8:19 ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2021-04-22 19:44 ` [patch 6/6] futex: Provide FUTEX_LOCK_PI2 to support " Thomas Gleixner
2021-04-23 22:20 ` André Almeida
2021-04-23 22:36 ` Thomas Gleixner [this message]
2021-06-23 8:19 ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2021-05-05 12:59 ` [patch 0/6] futex: Bugfixes and FUTEX_LOCK_PI2 Peter Zijlstra
2021-05-05 13:51 ` Kurt Kanzenbach
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