Re: [ 08/12] mac80211: zero initialize count field in ieee80211_tx_rate

[Mohammed Shafi Shajakhan]

On Monday 12 March 2012 09:25 PM, Mohammed Shafi Shajakhan wrote:
> Hi Ben,
>
> On Monday 12 March 2012 08:53 PM, Ben Hutchings wrote:
> > On Mon, 2012-03-12 at 12:22 +0530, Mohammed Shafi Shajakhan wrote:
> > > Hi Willy,
> > >
> > > > On Mon, Mar 12, 2012 at 10:06:23AM +0530, Mohammed Shafi Shajakhan
> > > > wrote:
> > > > > > So I'm pretty sure this patch is wrong for 2.6.32; it could be
> > > > > > backported but I don't think the change is necessary anyway.
> > > > >
> > > > > true, but i think its better to initialize the count = 0 rather than
> > > > > count = 1, though the older version driver checks for rate[i].idx>= 0
> > > > > in ath_rc_tx_status. while the ath_tx_status has no such iteration in
> > > > > the older driver code.
> > > >
> > > > In practice, if the patch brings nothing and not even correctness, I'd
> > > > rather drop it than make us believe that some issue is fixed. However
> > > > if you think it does happen to fix a real issue in 2.6.32 (possibly
> > > > combined with some other missing patch), please tell me so and I will
> > > > happily undelete it.
> > >
> > > we can drop it. also as there was no driver code checking for
> > > rate[i].count in the 2.6.32 driver. i am also not sure this fixes
> > > something in 2.6.32 but the patch itself is correct.
> > [...]
> >
> > Please read and answer the *whole* of my earlier message. The later
> > code in the rate_control_get_rate() function in 2.6.32 does appear to
> > depend on .count = 1, and there may be code elsewhere that does so too.
>
> are you referring to those code in tx.c ieee80211_tx_h_rate_control.
> sorry if i had again missed something.

if you are referring to that rate[0].count should be definitely 
non-zero. at least the first rate should be non-zero as the drivers rate 
control algorithm should properly fill it up, or mac80211's 
rate_control_send_low should fill it up by 1 for 'no ack frames'
(or)  max retries set by the driver for other frames(recently NULL func
 is added connection monitoring frame whose status will be needed).

--
thanks,
shafi
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