mac80211: make scan_sdata pointer usable with RCU
Making the scan_sdata pointer usable with RCU makes
it possible to dereference it in the RX path to see
if a received frame actually matches the interface
that is scanning. This is just preparations, making
the pointer __rcu.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 1ff04f6..704dcf8 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -293,7 +293,13 @@
return;
if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
- int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
+ int rc;
+
+ rc = drv_hw_scan(local,
+ rcu_dereference_protected(local->scan_sdata,
+ lockdep_is_held(&local->mtx)),
+ local->hw_scan_req);
+
if (rc == 0)
return;
}
@@ -394,7 +400,10 @@
if (!local->scan_req || local->scanning)
return;
- if (!ieee80211_can_scan(local, local->scan_sdata))
+ if (!ieee80211_can_scan(local,
+ rcu_dereference_protected(
+ local->scan_sdata,
+ lockdep_is_held(&local->mtx))))
return;
ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
@@ -405,9 +414,12 @@
unsigned long *next_delay)
{
int i;
- struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+ struct ieee80211_sub_if_data *sdata;
enum ieee80211_band band = local->hw.conf.channel->band;
+ sdata = rcu_dereference_protected(local->scan_sdata,
+ lockdep_is_held(&local->mtx));;
+
for (i = 0; i < local->scan_req->n_ssids; i++)
ieee80211_send_probe_req(
sdata, NULL,
@@ -439,7 +451,7 @@
if (!ieee80211_can_scan(local, sdata)) {
/* wait for the work to finish/time out */
local->scan_req = req;
- local->scan_sdata = sdata;
+ rcu_assign_pointer(local->scan_sdata, sdata);
return 0;
}
@@ -473,7 +485,7 @@
}
local->scan_req = req;
- local->scan_sdata = sdata;
+ rcu_assign_pointer(local->scan_sdata, sdata);
if (local->ops->hw_scan) {
__set_bit(SCAN_HW_SCANNING, &local->scanning);
@@ -533,7 +545,7 @@
ieee80211_recalc_idle(local);
local->scan_req = NULL;
- local->scan_sdata = NULL;
+ rcu_assign_pointer(local->scan_sdata, NULL);
}
return rc;
@@ -720,7 +732,8 @@
mutex_lock(&local->mtx);
- sdata = local->scan_sdata;
+ sdata = rcu_dereference_protected(local->scan_sdata,
+ lockdep_is_held(&local->mtx));
/* When scanning on-channel, the first-callback means completed. */
if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
@@ -741,7 +754,7 @@
int rc;
local->scan_req = NULL;
- local->scan_sdata = NULL;
+ rcu_assign_pointer(local->scan_sdata, NULL);
rc = __ieee80211_start_scan(sdata, req);
if (rc) {
@@ -893,7 +906,9 @@
if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
if (local->ops->cancel_hw_scan)
- drv_cancel_hw_scan(local, local->scan_sdata);
+ drv_cancel_hw_scan(local,
+ rcu_dereference_protected(local->scan_sdata,
+ lockdep_is_held(&local->mtx)));
goto out;
}