Re: In last setsid/tty locking changes...

[Alan Cox]

On Gwe, 2005-01-07 at 13:37, Marco Cipullo wrote:
> In last setsid/tty locking changes:
> +	down(&tty_sem);
>  	current->signal->tty = NULL;
> +	up(&tty_sem);
>  
>  	/* Block and flush all signals */
>  	sigfillset(&blocked);
> 
> Sorry for the silly question, but why is needed a semaphore to write just one 
> value without read/write nothing else?

Look at the tty init_dev code paths and it might make more sense. It
doesn't just say "protect this write" more importantly it says "don't do
this in parallel with tty setup"

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