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From: Thomas Gleixner <tglx@linutronix.de>
To: Michel Lespinasse <walken@google.com>
Cc: Darren Hart <darren@dvhart.com>, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	Matt Turner <mattst88@gmail.com>,
	Russell King <linux@arm.linux.org.uk>,
	David Howells <dhowells@redhat.com>,
	Tony Luck <tony.luck@intel.com>, Michal Simek <monstr@monstr.eu>,
	Ralf Baechle <ralf@linux-mips.org>,
	"James E.J. Bottomley" <jejb@parisc-linux.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Paul Mundt <lethal@linux-sh.org>,
	"David S. Miller" <davem@davemloft.net>,
	Chris Metcalf <cmetcalf@tilera.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] futex: cmpxchg_futex_value_locked API change
Date: Tue, 8 Mar 2011 21:17:11 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.2.00.1103082114270.2787@localhost6.localdomain6> (raw)
In-Reply-To: <20110307021127.GB31188@google.com>

On Sun, 6 Mar 2011, Michel Lespinasse wrote:
> The cmpxchg_futex_value_locked API was funny in that it returned either
> the original, user-exposed futex value OR an error code such as -EFAULT.
> This was confusing at best, and could be a source of livelocks in places
> that retry the cmpxchg_futex_value_locked after trying to fix the issue
> by running fault_in_user_writeable().
> 
> This change makes the cmpxchg_futex_value_locked API more similar to the
> get_futex_value_locked one, returning an error code and updating the
> original value through a reference argument.

Ack.

>  static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(int *uval, int __user *uaddr,
> +			      int oldval, int newval)

Can we please change the arguments to u32 while at it? The futex core
code uses u32 all over the place so those inlines should do the same.

Thanks,

	tglx

  parent reply	other threads:[~2011-03-08 20:18 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-07  2:11 Michel Lespinasse
2011-03-07  8:54 ` Martin Schwidefsky
2011-03-07 14:25 ` Chris Metcalf
2011-03-07 21:58 ` Luck, Tony
2011-03-08 20:17 ` Thomas Gleixner [this message]
2011-03-09 11:25   ` Michel Lespinasse
2011-03-09 15:04     ` Thomas Gleixner
2011-03-09 15:08     ` Martin Schwidefsky
2011-03-09 22:17       ` Michel Lespinasse
2011-03-09 17:50     ` Darren Hart
2011-03-10 18:55     ` Thomas Gleixner
2011-03-11  2:16       ` Michel Lespinasse
2011-03-11  2:47         ` [PATCH 1/3] futex: do not pagefault_disable in futex_atomic_cmpxchg_inatomic() Michel Lespinasse
2011-03-11 11:31           ` [tip:core/futexes] futex: Remove redundant " tip-bot for Michel Lespinasse
2011-03-13 22:49           ` [PATCH 1/3] futex: do not " Linus Torvalds
2011-03-14  0:55             ` Darren Hart
2011-03-14  1:15               ` Darren Hart
2011-03-14  9:13               ` Peter Zijlstra
2011-03-14  9:13             ` Thomas Gleixner
2011-03-14 13:56               ` Thomas Gleixner
2011-03-14 20:07                 ` Darren Hart
2011-03-14 20:15                 ` [tip:core/futexes] futex: Deobfuscate handle_futex_death() tip-bot for Thomas Gleixner
2011-03-14 20:16                 ` [tip:core/futexes] arm: Remove bogus comment in futex_atomic_cmpxchg_inatomic() tip-bot for Thomas Gleixner
2011-03-14  9:15             ` [PATCH 1/3] futex: do not pagefault_disable " Michel Lespinasse
2011-03-11  2:48         ` [PATCH 2/3] futex: cmpxchg_futex_value_locked API change Michel Lespinasse
2011-03-11 11:31           ` [tip:core/futexes] futex: Sanitize cmpxchg_futex_value_locked API tip-bot for Michel Lespinasse
2012-03-05  0:01           ` [regression] Re: [PATCH 2/3] " Jonathan Nieder
2012-03-05 23:21             ` Luck, Tony
2012-03-05 23:42               ` Jonathan Nieder
2012-03-08 20:59                 ` Émeric Maschino
2012-03-08 21:12                   ` Émeric Maschino
2012-04-15 21:35                     ` Émeric Maschino
2011-03-11  2:50         ` [PATCH 3/3] futex: fix futex operation types Michel Lespinasse
2011-03-11 11:32           ` [tip:core/futexes] futex: Sanitize futex ops argument types tip-bot for Michel Lespinasse
2011-03-09 11:08 ` [PATCH] futex: cmpxchg_futex_value_locked API change Michal Simek
2011-03-09 12:41 ` David Howells

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