Re: [PATCH v5] mac80211: Allow 0 for NL80211_MESHCONF_PLINK_TIMEOUT to disable STA expiration

[Johannes Berg <johannes@sipsolutions.net>]

On Tue, 2015-02-24 at 22:42 +0900, Masashi Honma wrote:
> Both wpa_supplicant and mac80211 has inactivity timer. By default
> wpa_supplicant will be timed out in 5 minutes and mac80211's it is 30 minutes.
> If wpa_supplicant uses more long timer than mac80211, wpa_supplicant will get
> unexpected disconnection by mac80211. This patch adds functionality of disabling
> mac80211 inactivity timer to avoid to prevent wpa_supplicant inactivity timer.
> 
> I have thought setting 0xffffffff to NL80211_MESHCONF_PLINK_TIMEOUT will solve
> this problem without this patch. But the approach does not work on 32 bit
> system. To explain the reason, I will show STA expiration rule in kernel. This
> is the expression.
> 
> (current jiffies) > (frame Rx jiffies + NL80211_MESHCONF_PLINK_TIMEOUT * 250)
> 
> On 32bit system, right side could be over flow and be unexpected small value if
> NL80211_MESHCONF_PLINK_TIMEOUT is sufficiently large. STA expiration occurs by
> this reason. So I made this patch.

Applied, I've reworded and rewrapped the commit log - in the future
please send commit logs with at most 72 characters per line.

johannes