From: Sam Leffler <sleffler@xxxxxxxxxxxx>
Add an NL80211_SCAN_FLAG_FLUSH flag that causes old bss cache
entries to be flushed on scan completion. This is useful for
collecting guaranteed fresh scan/survey result (e.g. on resume).
For normal scan, flushing only happens on successful completion
of a scan; i.e. it does not happen if the scan is aborted.
For scheduled scan, previous scan results are flushed everytime
when we get new scan results.
This feature is by default enabled. Drivers can disable it using
NL80211_FEATURE_DISABLE_SCAN_FLUSH flag.
Signed-off-by: Sam Leffler <sleffler@xxxxxxxxxxxx>
Tested-by: Amitkumar Karwar <akarwar@xxxxxxxxxxx>
Signed-off-by: Amitkumar Karwar <akarwar@xxxxxxxxxxx>
Signed-off-by: Bing Zhao <bzhao@xxxxxxxxxxx>
---
v4: "wiphy->features" is used instead of "wiphy->flags" to advertise
scan features;
Added support to disable scan flush if driver requests for it
explicitly;
Used msecs_to_jiffies() to convert time interval into jiffies
for comparison
(Johannes Berg)
v3: avoid static forward declaration (Johannes Berg)
include/linux/nl80211.h | 5 +++
include/net/cfg80211.h | 3 ++
net/wireless/nl80211.c | 14 +++++++---
net/wireless/scan.c | 66 ++++++++++++++++++++++++++++++++--------------
net/wireless/sme.c | 1 +
5 files changed, 65 insertions(+), 24 deletions(-)
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index c68e15e..6378d4a 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -3049,6 +3049,8 @@ enum nl80211_ap_sme_features {
* equals (SAE) with user space SME (NL80211_CMD_AUTHENTICATE) in station
* mode
* @NL80211_FEATURE_LOW_PRIORITY_SCAN: This driver supports low priority scan
+ * @NL80211_FEATURE_DISABLE_SCAN_FLUSH: This driver doesn't support scan flush
+ * feature
*/
enum nl80211_feature_flags {
NL80211_FEATURE_SK_TX_STATUS = 1 << 0,
@@ -3058,6 +3060,7 @@ enum nl80211_feature_flags {
NL80211_FEATURE_P2P_DEVICE_NEEDS_CHANNEL = 1 << 4,
NL80211_FEATURE_SAE = 1 << 5,
NL80211_FEATURE_LOW_PRIORITY_SCAN = 1 << 6,
+ NL80211_FEATURE_DISABLE_SCAN_FLUSH = 1 << 7,
};
/**
@@ -3100,9 +3103,11 @@ enum nl80211_connect_failed_reason {
* requests.
*
* @NL80211_SCAN_FLAG_LOW_PRIORITY: scan request has low priority
+ * @NL80211_SCAN_FLAG_FLUSH: flush cache before scanning
*/
enum nl80211_scan_flags {
NL80211_SCAN_FLAG_LOW_PRIORITY = 1<<0,
+ NL80211_SCAN_FLAG_FLUSH = 1<<1,
};
#endif /* __LINUX_NL80211_H */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 4724372..2837994 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1005,6 +1005,7 @@ struct cfg80211_ssid {
* @flags: bit field of flags controlling operation
* @rates: bitmap of rates to advertise for each band
* @wiphy: the wiphy this was for
+ * @scan_start: time (in jiffies) when the scan started
* @wdev: the wireless device to scan for
* @aborted: (internal) scan request was notified as aborted
* @no_cck: used to send probe requests at non CCK rate in 2GHz band
@@ -1023,6 +1024,7 @@ struct cfg80211_scan_request {
/* internal */
struct wiphy *wiphy;
+ unsigned long scan_start;
bool aborted;
bool no_cck;
@@ -1074,6 +1076,7 @@ struct cfg80211_sched_scan_request {
/* internal */
struct wiphy *wiphy;
struct net_device *dev;
+ unsigned long scan_start;
/* keep last */
struct ieee80211_channel *channels[0];
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index facaa11..fe8d7a9 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4371,8 +4371,10 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
if (info->attrs[NL80211_ATTR_SCAN_FLAGS]) {
request->flags = nla_get_u32(
info->attrs[NL80211_ATTR_SCAN_FLAGS]);
- if ((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
- !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) {
+ if (((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
+ !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) ||
+ ((request->flags & NL80211_SCAN_FLAG_FLUSH) &&
+ (wiphy->features & NL80211_FEATURE_DISABLE_SCAN_FLUSH))) {
err = -EOPNOTSUPP;
goto out_free;
}
@@ -4383,6 +4385,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
request->wdev = wdev;
request->wiphy = &rdev->wiphy;
+ request->scan_start = jiffies;
rdev->scan_req = request;
err = rdev->ops->scan(&rdev->wiphy, request);
@@ -4612,8 +4615,10 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
if (info->attrs[NL80211_ATTR_SCAN_FLAGS]) {
request->flags = nla_get_u32(
info->attrs[NL80211_ATTR_SCAN_FLAGS]);
- if ((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
- !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) {
+ if (((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
+ !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) ||
+ ((request->flags & NL80211_SCAN_FLAG_FLUSH) &&
+ (wiphy->features & NL80211_FEATURE_DISABLE_SCAN_FLUSH))) {
err = -EOPNOTSUPP;
goto out_free;
}
@@ -4622,6 +4627,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
request->dev = dev;
request->wiphy = &rdev->wiphy;
request->interval = interval;
+ request->scan_start = jiffies;
err = rdev->ops->sched_scan_start(&rdev->wiphy, dev, request);
if (!err) {
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 2005096..a8d5a9a 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -47,6 +47,27 @@ static void __cfg80211_unlink_bss(struct cfg80211_registered_device *dev,
kref_put(&bss->ref, bss_release);
}
+/* must hold dev->bss_lock! */
+static void __cfg80211_bss_expire(struct cfg80211_registered_device *dev,
+ unsigned long expire_time)
+{
+ struct cfg80211_internal_bss *bss, *tmp;
+ bool expired = false;
+
+ list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
+ if (atomic_read(&bss->hold))
+ continue;
+ if (!time_after(expire_time, bss->ts))
+ continue;
+
+ __cfg80211_unlink_bss(dev, bss);
+ expired = true;
+ }
+
+ if (expired)
+ dev->bss_generation++;
+}
+
void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
{
struct cfg80211_scan_request *request;
@@ -72,10 +93,17 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
if (wdev->netdev)
cfg80211_sme_scan_done(wdev->netdev);
- if (request->aborted)
+ if (request->aborted) {
nl80211_send_scan_aborted(rdev, wdev);
- else
+ } else {
+ if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
+ /* flush entries from previous scans */
+ spin_lock_bh(&rdev->bss_lock);
+ __cfg80211_bss_expire(rdev, request->scan_start);
+ spin_unlock_bh(&rdev->bss_lock);
+ }
nl80211_send_scan_done(rdev, wdev);
+ }
#ifdef CONFIG_CFG80211_WEXT
if (wdev->netdev && !request->aborted) {
@@ -126,16 +154,27 @@ EXPORT_SYMBOL(cfg80211_scan_done);
void __cfg80211_sched_scan_results(struct work_struct *wk)
{
struct cfg80211_registered_device *rdev;
+ struct cfg80211_sched_scan_request *request;
rdev = container_of(wk, struct cfg80211_registered_device,
sched_scan_results_wk);
+ request = rdev->sched_scan_req;
+
mutex_lock(&rdev->sched_scan_mtx);
/* we don't have sched_scan_req anymore if the scan is stopping */
- if (rdev->sched_scan_req)
- nl80211_send_sched_scan_results(rdev,
- rdev->sched_scan_req->dev);
+ if (request) {
+ if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
+ /* flush entries from previous scans */
+ spin_lock_bh(&rdev->bss_lock);
+ __cfg80211_bss_expire(rdev, request->scan_start);
+ spin_unlock_bh(&rdev->bss_lock);
+ request->scan_start =
+ jiffies + msecs_to_jiffies(request->interval);
+ }
+ nl80211_send_sched_scan_results(rdev, request->dev);
+ }
mutex_unlock(&rdev->sched_scan_mtx);
}
@@ -197,23 +236,9 @@ void cfg80211_bss_age(struct cfg80211_registered_device *dev,
}
}
-/* must hold dev->bss_lock! */
void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
{
- struct cfg80211_internal_bss *bss, *tmp;
- bool expired = false;
-
- list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
- if (atomic_read(&bss->hold))
- continue;
- if (!time_after(jiffies, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE))
- continue;
- __cfg80211_unlink_bss(dev, bss);
- expired = true;
- }
-
- if (expired)
- dev->bss_generation++;
+ __cfg80211_bss_expire(dev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
}
const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len)
@@ -962,6 +987,7 @@ int cfg80211_wext_siwscan(struct net_device *dev,
creq->ssids = (void *)&creq->channels[n_channels];
creq->n_channels = n_channels;
creq->n_ssids = 1;
+ creq->scan_start = jiffies;
/* translate "Scan on frequencies" request */
i = 0;
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index 055d596..07d717e 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -138,6 +138,7 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev)
request->wdev = wdev;
request->wiphy = &rdev->wiphy;
+ request->scan_start = jiffies;
rdev->scan_req = request;
--
1.7.0.4
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