cfg80211: age scan results on resume

Scanned BSS entries are timestamped with jiffies, which doesn't
increment across suspend and hibernate.  On resume, every BSS in the
scan list looks like it was scanned within the last 10 seconds,
irregardless of how long the machine was actually asleep.  Age scan
results on resume with the time spent during sleep so userspace has a
clue how old they really are.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/wireless/core.h b/net/wireless/core.h
index e29ad4cd464f3587fca6f06ff6892f1a6a04fc6f..5d0c682d737a499f6fff260667feba127259a07b 100644 (file)
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -49,6 +49,7 @@ struct cfg80211_registered_device {
        struct rb_root bss_tree;
        u32 bss_generation;
        struct cfg80211_scan_request *scan_req; /* protected by RTNL */
+       unsigned long suspend_at;
 
        /* must be last because of the way we do wiphy_priv(),
         * and it should at least be aligned to NETDEV_ALIGN */
@@ -113,5 +114,7 @@ void ieee80211_set_bitrate_flags(struct wiphy *wiphy);
 void wiphy_update_regulatory(struct wiphy *wiphy, enum reg_set_by setby);
 
 void cfg80211_bss_expire(struct cfg80211_registered_device *dev);
+void cfg80211_bss_age(struct cfg80211_registered_device *dev,
+                      unsigned long age_secs);
 
 #endif /* __NET_WIRELESS_CORE_H */

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index b1893c863b976188970877907edf8b4eeb12449b..9fad1631d6cbe5789967f57f87d12a0c21f25d4c 100644 (file)
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -61,6 +61,18 @@ static void bss_release(struct kref *ref)
        kfree(bss);
 }
 
+/* must hold dev->bss_lock! */
+void cfg80211_bss_age(struct cfg80211_registered_device *dev,
+                      unsigned long age_secs)
+{
+       struct cfg80211_internal_bss *bss;
+       unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
+
+       list_for_each_entry(bss, &dev->bss_list, list) {
+               bss->ts -= age_jiffies;
+       }
+}
+
 /* must hold dev->bss_lock! */
 void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
 {
@@ -584,6 +596,15 @@ static void ieee80211_scan_add_ies(struct iw_request_info *info,
        }
 }
 
+static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
+{
+       unsigned long end = jiffies;
+
+       if (end >= start)
+               return jiffies_to_msecs(end - start);
+
+       return jiffies_to_msecs(end + (MAX_JIFFY_OFFSET - start) + 1);
+}
 
 static char *
 ieee80211_bss(struct iw_request_info *info,
@@ -763,8 +784,8 @@ ieee80211_bss(struct iw_request_info *info,
                                                  &iwe, buf);
                memset(&iwe, 0, sizeof(iwe));
                iwe.cmd = IWEVCUSTOM;
-               sprintf(buf, " Last beacon: %dms ago",
-                       jiffies_to_msecs(jiffies - bss->ts));
+               sprintf(buf, " Last beacon: %ums ago",
+                       elapsed_jiffies_msecs(bss->ts));
                iwe.u.data.length = strlen(buf);
                current_ev = iwe_stream_add_point(info, current_ev,
                                                  end_buf, &iwe, buf);

diff --git a/net/wireless/sysfs.c b/net/wireless/sysfs.c
index 26a72b0797a09e5c6c2ff4595dab1309d007c627..15feaeb5ced5f3e15cac273ab13dc30ccd953154 100644 (file)
--- a/net/wireless/sysfs.c
+++ b/net/wireless/sysfs.c
@@ -60,6 +60,8 @@ static int wiphy_suspend(struct device *dev, pm_message_t state)
        struct cfg80211_registered_device *rdev = dev_to_rdev(dev);
        int ret = 0;
 
+       rdev->suspend_at = get_seconds();
+
        if (rdev->ops->suspend) {
                rtnl_lock();
                ret = rdev->ops->suspend(&rdev->wiphy);
@@ -74,6 +76,11 @@ static int wiphy_resume(struct device *dev)
        struct cfg80211_registered_device *rdev = dev_to_rdev(dev);
        int ret = 0;
 
+       /* Age scan results with time spent in suspend */
+       spin_lock_bh(&rdev->bss_lock);
+       cfg80211_bss_age(rdev, get_seconds() - rdev->suspend_at);
+       spin_unlock_bh(&rdev->bss_lock);
+
        if (rdev->ops->resume) {
                rtnl_lock();
                ret = rdev->ops->resume(&rdev->wiphy);