Re: [PATCH] powerpc: remove useless spinlock from mpc83xx watchdog

[Alan Cox]

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@xxxxxxxxxxxxxxxxxxx>

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/