Re: [PATCH] irda: irda-usb: use msecs_to_jiffies for conversions

[David Miller <davem@davemloft.net>]

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.

Agreed.