From: Catalin Marinas <catalin.marinas@arm.com>
To: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Further copy_from_user() discussion.
Date: Thu, 14 Apr 2005 10:36:47 +0100 [thread overview]
Message-ID: <tnxzmw1d7io.fsf@arm.com> (raw)
In-Reply-To: Pine.LNX.4.58.0504131342530.14888@shell4.speakeasy.net
Vadim Lobanov <vlobanov@speakeasy.net> wrote:
> 2. Would it be possible to eliminate the might_sleep() call in
> copy_from_user()? It seems that, very soon after, the __copy_from_user()
> macro does another might_sleep(), with very few instructions in between.
> But there might be some trick here that I'm missing.
might_sleep() is used for debugging the possible sleep while in an
atomic operation. I think it is safe to check this for all the calls
to copy_from_user(), no matter if the access is OK or not (memset
being used in the latter case). The same is for
__copy_from_user(). Anyway, if you don't enable
CONFIG_DEBUG_SPINLOCK_SLEEP, the might_sleep() macro is empty.
--
Catalin
next prev parent reply other threads:[~2005-04-14 9:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-13 20:52 Further copy_from_user() discussion Vadim Lobanov
2005-04-14 9:36 ` Catalin Marinas [this message]
2005-04-14 17:04 ` Vadim Lobanov
2005-04-15 10:14 ` Catalin Marinas
2005-04-15 15:55 ` Vadim Lobanov
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