From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 17 Feb 2018 13:17:41 +0100 From: Greg KH To: Quytelda Kahja Cc: gs051095@gmail.com, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Staging: gdm724x: tty: Fix macro argument reuse that could cause side-effects. Message-ID: <20180217121741.GC10940@kroah.com> References: <20180216222655.23919-1-quytelda@tamalin.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180216222655.23919-1-quytelda@tamalin.org> User-Agent: Mutt/1.9.3 (2018-01-21) X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, Feb 16, 2018 at 02:26:55PM -0800, Quytelda Kahja wrote: > Fix a coding style warning from checkpatch.pl. Use GNU extensions to create > references to the results of problem macro arguments when they are evaluated so > that they can be used safely multiple times. > > Signed-off-by: Quytelda Kahja > --- > drivers/staging/gdm724x/gdm_tty.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/drivers/staging/gdm724x/gdm_tty.c b/drivers/staging/gdm724x/gdm_tty.c > index fc7682c18f20..73d39fa86d10 100644 > --- a/drivers/staging/gdm724x/gdm_tty.c > +++ b/drivers/staging/gdm724x/gdm_tty.c > @@ -37,14 +37,22 @@ > > #define MUX_TX_MAX_SIZE 2048 > > -#define gdm_tty_send(n, d, l, i, c, b) (\ > - n->tty_dev->send_func(n->tty_dev->priv_dev, d, l, i, c, b)) > -#define gdm_tty_recv(n, c) (\ > - n->tty_dev->recv_func(n->tty_dev->priv_dev, c)) > -#define gdm_tty_send_control(n, r, v, d, l) (\ > - n->tty_dev->send_control(n->tty_dev->priv_dev, r, v, d, l)) > - > -#define GDM_TTY_READY(gdm) (gdm && gdm->tty_dev && gdm->port.count) > +#define gdm_tty_send(n, d, l, i, c, b) \ > + ({ typeof(n) n_ = (n); \ > + void *priv_dev = n_->tty_dev->priv_dev; \ > + n_->tty_dev->send_func(priv_dev, d, l, i, c, b); }) > +#define gdm_tty_recv(n, c) \ > + ({ typeof(n) n_ = (n); \ > + void *priv_dev = n_->tty_dev->priv_dev; \ > + n_->tty_dev->recv_func(priv_dev, c); }) > +#define gdm_tty_send_control(n, r, v, d, l) \ > + ({ typeof(n) n_ = (n); \ > + void *priv_dev = n_->tty_dev->priv_dev; \ > + n_->tty_dev->send_control(priv_dev, r, v, d, l); }) > + > +#define GDM_TTY_READY(gdm) \ > + ({ typeof(gdm) gdm_ = gdm; \ > + gdm_ && gdm_->tty_dev && gdm_->port.count; }) Ugh, that's a mess. How about just replacing the use of these odd macros with the "real" call instead? The fact that they are messing around with the tty_dev call directly is really strange and should be made a lot more obvious, as that probably needs to be fixed up. thanks, greg k-h