mac80211: move csa counters from sdata to beacon/presp
Having csa counters part of beacon and probe_resp
structures makes it easier to get rid of possible
races between setting a beacon and updating
counters on SMP systems by guaranteeing counters
are always consistent against given beacon struct.
While at it relax WARN_ON into WARN_ON_ONCE to
prevent spamming logs and racing.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
[remove pointless array check]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 3c80bf2..ed56f00 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2426,7 +2426,7 @@
u8 *beacon_data;
size_t beacon_data_len;
int i;
- u8 count = sdata->csa_current_counter;
+ u8 count = beacon->csa_current_counter;
switch (sdata->vif.type) {
case NL80211_IFTYPE_AP:
@@ -2445,46 +2445,53 @@
return;
}
+ rcu_read_lock();
for (i = 0; i < IEEE80211_MAX_CSA_COUNTERS_NUM; ++i) {
- u16 counter_offset_beacon =
- sdata->csa_counter_offset_beacon[i];
- u16 counter_offset_presp = sdata->csa_counter_offset_presp[i];
+ resp = rcu_dereference(sdata->u.ap.probe_resp);
- if (counter_offset_beacon) {
- if (WARN_ON(counter_offset_beacon >= beacon_data_len))
- return;
-
- beacon_data[counter_offset_beacon] = count;
- }
-
- if (sdata->vif.type == NL80211_IFTYPE_AP &&
- counter_offset_presp) {
- rcu_read_lock();
- resp = rcu_dereference(sdata->u.ap.probe_resp);
-
- /* If nl80211 accepted the offset, this should
- * not happen.
- */
- if (WARN_ON(!resp)) {
+ if (beacon->csa_counter_offsets[i]) {
+ if (WARN_ON_ONCE(beacon->csa_counter_offsets[i] >=
+ beacon_data_len)) {
rcu_read_unlock();
return;
}
- resp->data[counter_offset_presp] = count;
- rcu_read_unlock();
+
+ beacon_data[beacon->csa_counter_offsets[i]] = count;
}
+
+ if (sdata->vif.type == NL80211_IFTYPE_AP && resp)
+ resp->data[resp->csa_counter_offsets[i]] = count;
}
+ rcu_read_unlock();
}
u8 ieee80211_csa_update_counter(struct ieee80211_vif *vif)
{
struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+ struct beacon_data *beacon = NULL;
+ u8 count = 0;
- sdata->csa_current_counter--;
+ rcu_read_lock();
+
+ if (sdata->vif.type == NL80211_IFTYPE_AP)
+ beacon = rcu_dereference(sdata->u.ap.beacon);
+ else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
+ beacon = rcu_dereference(sdata->u.ibss.presp);
+ else if (ieee80211_vif_is_mesh(&sdata->vif))
+ beacon = rcu_dereference(sdata->u.mesh.beacon);
+
+ if (!beacon)
+ goto unlock;
+
+ beacon->csa_current_counter--;
/* the counter should never reach 0 */
- WARN_ON(!sdata->csa_current_counter);
+ WARN_ON_ONCE(!beacon->csa_current_counter);
+ count = beacon->csa_current_counter;
- return sdata->csa_current_counter;
+unlock:
+ rcu_read_unlock();
+ return count;
}
EXPORT_SYMBOL(ieee80211_csa_update_counter);
@@ -2494,7 +2501,6 @@
struct beacon_data *beacon = NULL;
u8 *beacon_data;
size_t beacon_data_len;
- int counter_beacon = sdata->csa_counter_offset_beacon[0];
int ret = false;
if (!ieee80211_sdata_running(sdata))
@@ -2532,10 +2538,10 @@
goto out;
}
- if (WARN_ON(counter_beacon > beacon_data_len))
+ if (WARN_ON_ONCE(beacon->csa_counter_offsets[0] > beacon_data_len))
goto out;
- if (beacon_data[counter_beacon] == 1)
+ if (beacon_data[beacon->csa_counter_offsets[0]] == 1)
ret = true;
out:
rcu_read_unlock();
@@ -2551,6 +2557,7 @@
bool is_template)
{
struct ieee80211_local *local = hw_to_local(hw);
+ struct beacon_data *beacon = NULL;
struct sk_buff *skb = NULL;
struct ieee80211_tx_info *info;
struct ieee80211_sub_if_data *sdata = NULL;
@@ -2572,8 +2579,8 @@
if (sdata->vif.type == NL80211_IFTYPE_AP) {
struct ieee80211_if_ap *ap = &sdata->u.ap;
- struct beacon_data *beacon = rcu_dereference(ap->beacon);
+ beacon = rcu_dereference(ap->beacon);
if (beacon) {
if (sdata->vif.csa_active) {
if (!is_template)
@@ -2616,34 +2623,34 @@
} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
struct ieee80211_hdr *hdr;
- struct beacon_data *presp = rcu_dereference(ifibss->presp);
- if (!presp)
+ beacon = rcu_dereference(ifibss->presp);
+ if (!beacon)
goto out;
if (sdata->vif.csa_active) {
if (!is_template)
ieee80211_csa_update_counter(vif);
- ieee80211_set_csa(sdata, presp);
+ ieee80211_set_csa(sdata, beacon);
}
- skb = dev_alloc_skb(local->tx_headroom + presp->head_len +
+ skb = dev_alloc_skb(local->tx_headroom + beacon->head_len +
local->hw.extra_beacon_tailroom);
if (!skb)
goto out;
skb_reserve(skb, local->tx_headroom);
- memcpy(skb_put(skb, presp->head_len), presp->head,
- presp->head_len);
+ memcpy(skb_put(skb, beacon->head_len), beacon->head,
+ beacon->head_len);
hdr = (struct ieee80211_hdr *) skb->data;
hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_BEACON);
} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
- struct beacon_data *bcn = rcu_dereference(ifmsh->beacon);
- if (!bcn)
+ beacon = rcu_dereference(ifmsh->beacon);
+ if (!beacon)
goto out;
if (sdata->vif.csa_active) {
@@ -2655,40 +2662,42 @@
*/
ieee80211_csa_update_counter(vif);
- ieee80211_set_csa(sdata, bcn);
+ ieee80211_set_csa(sdata, beacon);
}
if (ifmsh->sync_ops)
- ifmsh->sync_ops->adjust_tbtt(sdata, bcn);
+ ifmsh->sync_ops->adjust_tbtt(sdata, beacon);
skb = dev_alloc_skb(local->tx_headroom +
- bcn->head_len +
+ beacon->head_len +
256 + /* TIM IE */
- bcn->tail_len +
+ beacon->tail_len +
local->hw.extra_beacon_tailroom);
if (!skb)
goto out;
skb_reserve(skb, local->tx_headroom);
- memcpy(skb_put(skb, bcn->head_len), bcn->head, bcn->head_len);
+ memcpy(skb_put(skb, beacon->head_len), beacon->head,
+ beacon->head_len);
ieee80211_beacon_add_tim(sdata, &ifmsh->ps, skb, is_template);
if (offs) {
- offs->tim_offset = bcn->head_len;
- offs->tim_length = skb->len - bcn->head_len;
+ offs->tim_offset = beacon->head_len;
+ offs->tim_length = skb->len - beacon->head_len;
}
- memcpy(skb_put(skb, bcn->tail_len), bcn->tail, bcn->tail_len);
+ memcpy(skb_put(skb, beacon->tail_len), beacon->tail,
+ beacon->tail_len);
} else {
WARN_ON(1);
goto out;
}
/* CSA offsets */
- if (offs) {
+ if (offs && beacon) {
int i;
for (i = 0; i < IEEE80211_MAX_CSA_COUNTERS_NUM; i++) {
- u16 csa_off = sdata->csa_counter_offset_beacon[i];
+ u16 csa_off = beacon->csa_counter_offsets[i];
if (!csa_off)
continue;