lkml.org 
[lkml]   [2015]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH] irda: irda-usb: use msecs_to_jiffies for conversions
    From
    Date
    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





    \
     
     \ /
      Last update: 2015-05-19 23:21    [W:4.211 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site