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From: Stafford Horne <shorne@gmail.com>
To: David Laight <David.Laight@aculab.com>
Cc: 'Arnd Bergmann' <arnd@kernel.org>,
	Michal Simek <monstr@monstr.eu>,
	Christoph Hellwig <hch@infradead.org>,
	Arnd Bergmann <arnd@arndb.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] microblaze: remove CONFIG_SET_FS
Date: Fri, 11 Feb 2022 07:23:42 +0900	[thread overview]
Message-ID: <YgWQbpBX6eJNozGM@antec> (raw)
In-Reply-To: <cc2a0d0eb77b4ace872263db7bf0c115@AcuMS.aculab.com>

On Thu, Feb 10, 2022 at 02:21:07PM +0000, David Laight wrote:
> From: Arnd Bergmann
> > static inline int __range_ok(unsigned long addr, unsigned long size)
> > {
> >         return size <= TASK_SIZE && addr <= (TASK_SIZE - size);
> > }
> > 
> > since 'size' is usually constant, so this turns into a single comparison
> > against a compile-time constant.
> 
> Hmmm... maybe there should be a comment that it is the same as
> the more obvious:
> 	(addr <= TASK_SIZE && addr <= TASK_SIZE - size)
> but is better for constant size.
> (Provided TASK_SIZE is a constant.)

Ah, this makes sense that.  I might as well revert the OpenRISC patch for this.
Though, we shall move to the generic version in the end.

With ideal compare:

    -rwxrwxr-x. 1 shorne shorne 6011932 Feb  9 17:57 vmlinux

With comparing (size <= TASK_SIZE && addr <= TASK_SIZE - size):

    -rwxrwxr-x. 1 shorne shorne 6003556 Feb 11 07:18 vmlinux

-Stafford

  parent reply	other threads:[~2022-02-10 22:23 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-09 14:48 [PATCH] microblaze: remove CONFIG_SET_FS Arnd Bergmann
2022-02-10  9:36 ` David Laight
2022-02-10 13:29   ` Arnd Bergmann
2022-02-10 14:21     ` David Laight
2022-02-10 14:53       ` Arnd Bergmann
2022-02-10 22:23       ` Stafford Horne [this message]
  -- strict thread matches above, loose matches on Subject: below --
2022-01-17 13:24 [PATCH 03/10] exit: Move oops specific logic from do_exit into make_task_dead Arnd Bergmann
2022-01-17 13:27 ` [PATCH] microblaze: remove CONFIG_SET_FS Arnd Bergmann
2022-02-09 13:50   ` Michal Simek
2022-02-09 13:52     ` Christoph Hellwig
2022-02-09 14:03       ` Michal Simek
2022-02-09 14:40     ` Arnd Bergmann
2022-02-09 14:44       ` Michal Simek
2022-02-09 14:54         ` Arnd Bergmann
2022-02-09 23:31           ` Stafford Horne
2022-02-11  0:17             ` Stafford Horne
2022-02-11 16:59               ` Arnd Bergmann
2022-02-11 17:46                 ` Linus Torvalds
2022-02-11 20:57                   ` Arnd Bergmann
2022-02-11 21:10                     ` Eric W. Biederman
2022-02-11 22:21                       ` Stafford Horne
2022-02-14  7:41                   ` Christoph Hellwig
2022-02-14  7:50                 ` Christoph Hellwig
2022-02-14 16:20                   ` Arnd Bergmann

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