mac80211: round station cleanup timer

The station cleanup timer runs every ten seconds, the exact
timing is not relevant at all so it can well run together with
other things to save power.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index e849155..cfd8ee9 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/skbuff.h>
 #include <linux/if_arp.h>
+#include <linux/timer.h>
 
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
@@ -306,7 +307,8 @@
 	}
 	read_unlock_bh(&local->sta_lock);
 
-	local->sta_cleanup.expires = jiffies + STA_INFO_CLEANUP_INTERVAL;
+	local->sta_cleanup.expires =
+		round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
 	add_timer(&local->sta_cleanup);
 }
 
@@ -345,7 +347,8 @@
 	INIT_LIST_HEAD(&local->sta_list);
 
 	init_timer(&local->sta_cleanup);
-	local->sta_cleanup.expires = jiffies + STA_INFO_CLEANUP_INTERVAL;
+	local->sta_cleanup.expires =
+		round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
 	local->sta_cleanup.data = (unsigned long) local;
 	local->sta_cleanup.function = sta_info_cleanup;