Re: [PATCH] brcmsmac: fix NULL pointer crash in brcms_c_regd_init()

[Seth Forshee <seth.forshee@canonical.com>]

On Tue, Jun 26, 2012 at 11:46:33AM +0200, Arend van Spriel wrote:
> > This looks fine, but it strikes me that it might simplify things a bit
> > to change the loop to iterate over over wlc->pub->_nbands instead. The
> > difference is pretty minor though, and since John has already applied
> > this patch there's probably no reason to change it.
> 
> I considered that but the iterator is used as index in the wiphy.band[]
> array further in the loop. So that would require a bit more rework of
> the loop

It's really not that bad though. I pasted an (untested) patch below.
But like I said before, the difference is pretty minor so I'm okay with
either.

> (although the internal band index and the one from cfg80211 match).

While this is true, I wouldn't want to build that assumption into the
code. Maybe there should be macros to map between the internal and
cfg80211 band indices.


diff --git a/drivers/net/wireless/brcm80211/brcmsmac/channel.c b/drivers/net/wireless/brcm80211/brcmsmac/channel.c
index 2d365d3..2c10bbe 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/channel.c
+++ b/drivers/net/wireless/brcm80211/brcmsmac/channel.c
@@ -760,23 +760,17 @@ void brcms_c_regd_init(struct brcms_c_info *wlc)
 	struct ieee80211_channel *ch;
 	struct brcms_chanvec sup_chan;
 	struct brcms_band *band;
-	int band_idx, i;
+	uint band_idx, i;
 
 	/* Disable any channels not supported by the phy */
-	for (band_idx = 0; band_idx < IEEE80211_NUM_BANDS; band_idx++) {
-		if (band_idx == IEEE80211_BAND_2GHZ)
-			band = wlc->bandstate[BAND_2G_INDEX];
-		else
-			band = wlc->bandstate[BAND_5G_INDEX];
-
-		/* skip if band not initialized */
-		if (band->pi == NULL)
-			continue;
+	for (band_idx = 0; band_idx < wlc->pub->_nbands; band_idx++) {
+		band = wlc->bandstate[band_idx];
+		sband = wiphy->bands[band_idx == BAND_2G_INDEX ?
+				     IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ];
 
 		wlc_phy_chanspec_band_validch(band->pi, band->bandtype,
 					      &sup_chan);
 
-		sband = wiphy->bands[band_idx];
 		for (i = 0; i < sband->n_channels; i++) {
 			ch = &sband->channels[i];
 			if (!isset(sup_chan.vec, ch->hw_value))