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mac80211: move csa counters from sdata to beacon/presp

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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>
This commit is contained in:
Michal Kazior
2014-06-05 14:21:36 +02:00
committed by Johannes Berg
parent b49328361b
commit af296bdb8d
5 changed files with 115 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/mac80211/tx.c
+56 -47
View File
@@ -2426,7 +2426,7 @@ static void ieee80211_set_csa(struct ieee80211_sub_if_data *sdata,
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 @@ static void ieee80211_set_csa(struct ieee80211_sub_if_data *sdata,
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 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
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 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
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 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
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 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
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 @@ __ieee80211_beacon_get(struct ieee80211_hw *hw,
} 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_beacon_get(struct ieee80211_hw *hw,
*/
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;