Messages in this thread | | | Subject | Re: [PATCH] irda: irda-usb: use msecs_to_jiffies for conversions | From | Joe Perches <> | Date | Tue, 19 May 2015 14:09:07 -0700 |
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On Tue, 2015-05-19 at 16:45 -0400, David Miller wrote: > From: Joe Perches <joe@perches.com> > Date: Tue, 19 May 2015 07:32:15 -0700 > > > On Tue, 2015-05-19 at 12:51 +0200, Nicholas Mc Guire wrote: > >> Converting milliseconds to jiffies by "val * HZ / 1000" is technically > >> is not a clean solution as it does not handle all corner cases correctly. > >> By changing the conversion to use msecs_to_jiffies(val) conversion is > >> correct in all cases. > >> > >> in the current code: > >> mod_timer(&self->rx_defer_timer, jiffies + (10 * HZ / 1000)); > >> for HZ < 100 (e.g. CONFIG_HZ == 64|32 in alpha) this effectively results > >> in no delay at all. > > [] > >> diff --git a/drivers/net/irda/irda-usb.c b/drivers/net/irda/irda-usb.c > > [] > >> @@ -848,7 +848,9 @@ static void irda_usb_receive(struct urb *urb) > >> * Jean II */ > >> self->rx_defer_timer.function = irda_usb_rx_defer_expired; > >> self->rx_defer_timer.data = (unsigned long) urb; > >> - mod_timer(&self->rx_defer_timer, jiffies + (10 * HZ / 1000)); > >> + mod_timer(&self->rx_defer_timer, > >> + jiffies + (msecs_to_jiffies(10))); > > > > The unnecessary () around msecs_to_jiffies could be removed.
The other thing that could be done is to use max(1ul, msecs_to_jiffies()) so that there's always some delay even if HZ <= 50
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