From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Kumar Gala <galak@gate.crashing.org>
Cc: Andrew Morton <akpm@osdl.org>,
wim@iguana.be, linux-kernel@vger.kernel.org,
linuxppc-embedded@ozlabs.org
Subject: Re: [PATCH] powerpc: remove useless spinlock from mpc83xx watchdog
Date: Thu, 19 Jan 2006 09:49:16 +0000 [thread overview]
Message-ID: <1137664156.8471.16.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.44.0601190057130.8484-100000@gate.crashing.org>
On Iau, 2006-01-19 at 00:58 -0600, Kumar Gala wrote:
> Since we can only open the watchdog once having a spinlock to protect
> multiple access is pointless.
>
> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
NAK
This is a common mistake.
open is called on the open() call and is indeed in this case 'single
open', but file handles can be inherited and many users may have access
to a single file handle.
eg
f = open("/dev/watchdog", O_RDWR);
fork();
while(1) {
write(f, "Boing", 5);
}
Alan
next prev parent reply other threads:[~2006-01-19 10:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-19 6:58 [PATCH] powerpc: remove useless spinlock from mpc83xx watchdog Kumar Gala
2006-01-19 9:49 ` Alan Cox [this message]
2006-01-19 14:21 ` Kumar Gala
2006-01-19 16:48 ` Marcelo Tosatti
2006-01-19 22:12 ` Alan Cox
2006-01-20 11:55 ` Wim Van Sebroeck
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