From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 28 Oct 2015 14:41:35 +0000 From: Nicholas Mc Guire To: Jiri Slaby Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, Nicholas Mc Guire , Hans de Goede , Mauro Carvalho Chehab , Oliver Neukum Subject: Re: [PATCH 3.12 117/123] [media] gscpa_m5602: use msecs_to_jiffies for conversions Message-ID: <20151028144135.GA17497@osadl.at> References: <582a72cd28521eabc4bebb29bbdc5ce0bf10c082.1446021556.git.jslaby@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <582a72cd28521eabc4bebb29bbdc5ce0bf10c082.1446021556.git.jslaby@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Wed, Oct 28, 2015 at 02:53:48PM +0100, Jiri Slaby wrote: > From: Nicholas Mc Guire > > 3.12-stable review patch. If anyone has any objections, please let me know. > > =============== > > commit 63f2f417526fc54191f2b813f72dc1d5322bede8 upstream. > > API compliance scanning with coccinelle flagged: > ./drivers/media/usb/gspca/m5602/m5602_s5k83a.c:180:9-25: > WARNING: timeout (100) seems HZ dependent > > Numeric constants passed to schedule_timeout() make the effective > timeout HZ dependent which makes little sense in a polling loop for > the cameras rotation state. > Fixed up by converting the constant to jiffies with msecs_to_jiffies() > > Signed-off-by: Nicholas Mc Guire > Signed-off-by: Hans de Goede > Signed-off-by: Mauro Carvalho Chehab > Cc: Oliver Neukum > Signed-off-by: Jiri Slaby > --- > drivers/media/usb/gspca/m5602/m5602_s5k83a.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/usb/gspca/m5602/m5602_s5k83a.c b/drivers/media/usb/gspca/m5602/m5602_s5k83a.c > index 7cbc3a00bda8..bf6b215438e3 100644 > --- a/drivers/media/usb/gspca/m5602/m5602_s5k83a.c > +++ b/drivers/media/usb/gspca/m5602/m5602_s5k83a.c > @@ -177,7 +177,7 @@ static int rotation_thread_function(void *data) > __s32 vflip, hflip; > > set_current_state(TASK_INTERRUPTIBLE); > - while (!schedule_timeout(100)) { > + while (!schedule_timeout(msecs_to_jiffies(100))) { > if (mutex_lock_interruptible(&sd->gspca_dev.usb_lock)) > break; > Note that there were some concerns regarding using msecs_to_jiffies rather than explicit conversion where gcc can do constant folding (so in this case something like (100 * HZ / 1000) this was mitigated by the following pathes to kbuild see https://lkml.org/lkml/2015/5/28/524 https://lkml.org/lkml/2015/5/28/525 in this case this does not really apply as the numeric 100 is actually a bug - but there might be some performance concerns if too many such conversions are added (there were all together about 30 such cases). thx! hofrat