Re: [PATCH] brcmfmac: cfg80211: use msecs_to_jiffies for time conversion

From: Nicholas Mc Guire
Date: Wed Mar 18 2015 - 02:45:16 EST


On Tue, 17 Mar 2015, Joe Perches wrote:

> On Tue, 2015-03-17 at 08:06 -0400, Nicholas Mc Guire wrote:
> > Converting milliseconds to jiffies by "val * HZ / 1000" is technically
> > OK but msecs_to_jiffies(val) is the cleaner solution and handles all
> > corner cases correctly. This is a minor API consolidation only and
> > should make things more readable.
>
> Hi Nicholas
>
> These API consolidation changes now always have a function
> call when the compiler may have previously been able to
> optimize out the "constant * HZ / 1000" calculation.
>
> Perhaps the [um]secs_to_jiffies calls should be indirected
> with yet another static inline with a __builtin_constant_p()
> test so that the function calls can again be avoided when
> possible.

will give it a try

>
> (and a trivial style note)
>
> > diff --git a/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c
> []
> > @@ -1110,7 +1110,7 @@ brcmf_cfg80211_escan(struct wiphy *wiphy, struct brcmf_cfg80211_vif *vif,
> >
> > /* Arm scan timeout timer */
> > mod_timer(&cfg->escan_timeout, jiffies +
> > - WL_ESCAN_TIMER_INTERVAL_MS * HZ / 1000);
> > + msecs_to_jiffies(WL_ESCAN_TIMER_INTERVAL_MS));
>
> It may be nicer to keep the arithmetic on one line

sorry that was plain carelessness afer it went over 80 char.

>
> mod_timer(&cfg->escan_timeout,
> jiffies + msecs_to_jiffies(WL_ESCAN_TIMER_INTERVAL_MS));
>

thx!
hofrat
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