linux-kernel - Re: [PATCH] tty: replace mutex_lock() with tty_write

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Date:	Fri, 22 Nov 2013 11:29:07 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	walter harms <wharms@....de>
Cc:	Andreas Platschek <andi.platschek@...il.com>,
	gregkh@...uxfoundation.org, jslaby@...e.cz,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] tty: replace mutex_lock() with tty_write_lock()

On Fri, Nov 22, 2013 at 09:09:15AM +0100, walter harms wrote:
> 
> 
> Am 21.11.2013 20:12, schrieb Andreas Platschek:
> > Use tty_write_lock()/tty_write_unlock() consistently.
> > 
> > This takes care of the following sparse warning:
> > drivers/tty/tty_io.c:1169:17: warning: context imbalance in 'tty_write_message' - unexpected unlock
> > 
> > Signed-off-by: Andreas Platschek <andi.platschek@...il.com>
> > ---
> >  drivers/tty/tty_io.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
> > index 3a1a01a..13dca92 100644
> > --- a/drivers/tty/tty_io.c
> > +++ b/drivers/tty/tty_io.c
> > @@ -1165,7 +1165,7 @@ out:
> >  void tty_write_message(struct tty_struct *tty, char *msg)
> >  {
> >  	if (tty) {
> > -		mutex_lock(&tty->atomic_write_lock);
> > +		tty_write_lock(tty,0);
> >  		tty_lock(tty);
> >  		if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
> >  			tty_unlock(tty);
> 
> i am not an expert on this but you may need to replace that tty_unlock() with tty_write_unlock().

No.  The original code is correct.

regards,
dan carpenter

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