From: Thomas Gleixner <tglx@linutronix•de>
To: Linus Torvalds <torvalds@linux-foundation•org>
Cc: LKML <linux-kernel@vger•kernel.org>,
"Peter Zijlstra" <peterz@infradead•org>,
"Darren Hart" <dvhart@infradead•org>,
"Davidlohr Bueso" <dave@stgolabs•net>,
"André Almeida" <andrealmeid@igalia•com>,
"kernel test robot" <lkp@intel•com>,
"Russell King" <linux@armlinux•org.uk>,
linux-arm-kernel@lists•infradead.org, x86@kernel•org,
"Madhavan Srinivasan" <maddy@linux•ibm.com>,
"Michael Ellerman" <mpe@ellerman•id.au>,
"Nicholas Piggin" <npiggin@gmail•com>,
"Christophe Leroy" <christophe.leroy@csgroup•eu>,
linuxppc-dev@lists•ozlabs.org, "Paul Walmsley" <pjw@kernel•org>,
"Palmer Dabbelt" <palmer@dabbelt•com>,
linux-riscv@lists•infradead.org,
"Heiko Carstens" <hca@linux•ibm.com>,
"Christian Borntraeger" <borntraeger@linux•ibm.com>,
"Sven Schnelle" <svens@linux•ibm.com>,
linux-s390@vger•kernel.org,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios•com>,
"Andrew Cooper" <andrew.cooper3@citrix•com>,
"David Laight" <david.laight.linux@gmail•com>,
"Julia Lawall" <Julia.Lawall@inria•fr>,
"Nicolas Palix" <nicolas.palix@imag•fr>,
"Alexander Viro" <viro@zeniv•linux.org.uk>,
"Christian Brauner" <brauner@kernel•org>,
"Jan Kara" <jack@suse•cz>,
linux-fsdevel@vger•kernel.org
Subject: Re: [patch V4 10/12] futex: Convert to scoped user access
Date: Thu, 23 Oct 2025 20:44:13 +0200 [thread overview]
Message-ID: <873479xxtu.ffs@tglx> (raw)
In-Reply-To: <CAHk-=wgLAJuJ8SP8NiSGbXJQMdxiPkBN32EvAy9R8kCnva4dfg@mail.gmail.com>
On Wed, Oct 22 2025 at 05:16, Linus Torvalds wrote:
> On Wed, 22 Oct 2025 at 02:49, Thomas Gleixner <tglx@linutronix•de> wrote:
>>
>> From: Thomas Gleixner <tglx@linutronix•de>
>>
>> Replace the open coded implementation with the new get/put_user_scoped()
>> helpers.
>
> Well, "scoped" here makes no sense in the name, since it isn't scoped
> in any way, it just uses the scoped helpers.
I know. Did not come up with a sensible name so far.
> I also wonder if we should just get rid of the futex_get/put_value()
> macros entirely. I did those masked user access things them long ago
> because that code used "__get_user()" and "__put_user()", and I was
> removing those helpers and making it match the pattern elsewhere, but
> I do wonder if there is any advantage left to them all.
>
> On x86, just using "get_user()" and "put_user()" should work fine now.
> Yes, they check the address, but these days *those* helpers use that
> masked user address trick too, so there is no real cost to it.
>
> The only cost would be the out-of-line function call, I think. Maybe
> that is a sufficiently big cost here.
I'll have a look at the usage sites.
But as you said out-of-line function call it occured to me that these
helpers might be just named get/put_user_inline(). Hmm?
Thanks,
tglx
next prev parent reply other threads:[~2025-10-23 18:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-22 12:49 [patch V4 00/12] uaccess: Provide and use scopes for user access Thomas Gleixner
2025-10-22 12:49 ` [patch V4 01/12] ARM: uaccess: Implement missing __get_user_asm_dword() Thomas Gleixner
2025-10-22 12:49 ` [patch V4 02/12] uaccess: Provide ASM GOTO safe wrappers for unsafe_*_user() Thomas Gleixner
2025-10-22 12:49 ` [patch V4 03/12] x86/uaccess: Use unsafe wrappers for ASM GOTO Thomas Gleixner
2025-10-22 12:49 ` [patch V4 04/12] powerpc/uaccess: " Thomas Gleixner
2025-10-22 12:49 ` [patch V4 05/12] riscv/uaccess: " Thomas Gleixner
2025-10-22 12:49 ` [patch V4 06/12] s390/uaccess: " Thomas Gleixner
2025-10-22 15:00 ` Heiko Carstens
2025-10-22 12:49 ` [patch V4 07/12] uaccess: Provide scoped user access regions Thomas Gleixner
2025-10-22 14:20 ` David Laight
2025-10-22 14:23 ` Peter Zijlstra
2025-10-22 12:49 ` [patch V4 08/12] uaccess: Provide put/get_user_scoped() Thomas Gleixner
2025-10-22 12:49 ` [patch V4 09/12] [RFC] coccinelle: misc: Add scoped_$MODE_access() checker script Thomas Gleixner
2025-10-22 12:49 ` [patch V4 10/12] futex: Convert to scoped user access Thomas Gleixner
2025-10-22 15:16 ` Linus Torvalds
2025-10-23 18:44 ` Thomas Gleixner [this message]
2025-10-23 19:26 ` Linus Torvalds
2025-10-23 21:14 ` David Laight
2025-10-22 12:49 ` [patch V4 11/12] x86/futex: " Thomas Gleixner
2025-10-22 12:49 ` [patch V4 12/12] select: " Thomas Gleixner
2025-10-22 13:28 ` [patch V4 00/12] uaccess: Provide and use scopes for " Peter Zijlstra
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