wifi: mac80211: add and use a link iteration macro

In the channel context code we have quite a few instances
of nested loops iterating the interfaces and then links.
Add a new for_each_sdata_link() macro and use it. Also,
since it's easier, convert all the loops and a few other
places away from RCU as we now hold the wiphy mutex
everywhere anyway.

This does cause a little bit more work (such as checking
interface types for each link of an interface rather than
not iterating links in some cases), but that's not a huge
issue and seems like an acceptable trade-off, readability
is important too.

Link: https://msgid.link/20240129194108.7240829bd96d.I5ccbb8dd019cbcb5326c85d76121359225d6541a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index f1cef332e4dbe14d75f4bc9f6ac5bc23958c4363..c84449bdc9284107635eabe8f666bf8e41141dac 100644 (file)
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -211,7 +211,7 @@ static enum nl80211_chan_width ieee80211_get_sta_bw(struct sta_info *sta,
        enum ieee80211_sta_rx_bandwidth width;
        struct link_sta_info *link_sta;
 
-       link_sta = rcu_dereference(sta->link[link_id]);
+       link_sta = wiphy_dereference(sta->local->hw.wiphy, sta->link[link_id]);
 
        /* no effect if this STA has no presence on this link */
        if (!link_sta)
@@ -249,9 +249,10 @@ static enum nl80211_chan_width ieee80211_get_sta_bw(struct sta_info *sta,
 }
 
 static enum nl80211_chan_width
-ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata,
-                             unsigned int link_id)
+ieee80211_get_max_required_bw(struct ieee80211_link_data *link)
 {
+       struct ieee80211_sub_if_data *sdata = link->sdata;
+       unsigned int link_id = link->link_id;
        enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
        struct sta_info *sta;
 
@@ -267,31 +268,25 @@ ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata,
 }
 
 static enum nl80211_chan_width
-ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
-                                         struct ieee80211_chanctx *ctx,
-                                         struct ieee80211_link_data *rsvd_for)
+ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
+                                     struct ieee80211_chanctx *ctx,
+                                     struct ieee80211_link_data *rsvd_for)
 {
+       struct ieee80211_sub_if_data *sdata;
+       struct ieee80211_link_data *link;
        enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
-       struct ieee80211_vif *vif = &sdata->vif;
-       int link_id;
 
-       rcu_read_lock();
-       for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
+       for_each_sdata_link(local, link) {
                enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
-               struct ieee80211_link_data *link =
-                       rcu_dereference(sdata->link[link_id]);
-
-               if (!link)
-                       continue;
 
                if (link != rsvd_for &&
                    rcu_access_pointer(link->conf->chanctx_conf) != &ctx->conf)
                        continue;
 
-               switch (vif->type) {
+               switch (link->sdata->vif.type) {
                case NL80211_IFTYPE_AP:
                case NL80211_IFTYPE_AP_VLAN:
-                       width = ieee80211_get_max_required_bw(sdata, link_id);
+                       width = ieee80211_get_max_required_bw(link);
                        break;
                case NL80211_IFTYPE_STATION:
                        /*
@@ -300,7 +295,7 @@ ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
                         * account also for TDLS peers
                         */
                        width = max(link->conf->chanreq.oper.width,
-                                   ieee80211_get_max_required_bw(sdata, link_id));
+                                   ieee80211_get_max_required_bw(link));
                        break;
                case NL80211_IFTYPE_P2P_DEVICE:
                case NL80211_IFTYPE_NAN:
@@ -321,40 +316,13 @@ ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
 
                max_bw = max(max_bw, width);
        }
-       rcu_read_unlock();
-
-       return max_bw;
-}
-
-static enum nl80211_chan_width
-ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
-                                     struct ieee80211_chanctx *ctx,
-                                     struct ieee80211_link_data *rsvd_for)
-{
-       struct ieee80211_sub_if_data *sdata;
-       enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
-
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               enum nl80211_chan_width width;
-
-               if (!ieee80211_sdata_running(sdata))
-                       continue;
-
-               width = ieee80211_get_chanctx_vif_max_required_bw(sdata, ctx,
-                                                                 rsvd_for);
-
-               max_bw = max(max_bw, width);
-       }
 
        /* use the configured bandwidth in case of monitor interface */
-       sdata = rcu_dereference(local->monitor_sdata);
+       sdata = wiphy_dereference(local->hw.wiphy, local->monitor_sdata);
        if (sdata &&
            rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &ctx->conf)
                max_bw = max(max_bw, ctx->conf.def.width);
 
-       rcu_read_unlock();
-
        return max_bw;
 }
 
@@ -582,26 +550,14 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
 
 bool ieee80211_is_radar_required(struct ieee80211_local *local)
 {
-       struct ieee80211_sub_if_data *sdata;
+       struct ieee80211_link_data *link;
 
        lockdep_assert_wiphy(local->hw.wiphy);
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               unsigned int link_id;
-
-               for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-                       struct ieee80211_link_data *link;
-
-                       link = rcu_dereference(sdata->link[link_id]);
-
-                       if (link && link->radar_required) {
-                               rcu_read_unlock();
-                               return true;
-                       }
-               }
+       for_each_sdata_link(local, link) {
+               if (link->radar_required)
+                       return true;
        }
-       rcu_read_unlock();
 
        return false;
 }
@@ -611,38 +567,19 @@ ieee80211_chanctx_radar_required(struct ieee80211_local *local,
                                 struct ieee80211_chanctx *ctx)
 {
        struct ieee80211_chanctx_conf *conf = &ctx->conf;
-       struct ieee80211_sub_if_data *sdata;
-       bool required = false;
+       struct ieee80211_link_data *link;
 
        lockdep_assert_wiphy(local->hw.wiphy);
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               unsigned int link_id;
-
-               if (!ieee80211_sdata_running(sdata))
+       for_each_sdata_link(local, link) {
+               if (rcu_access_pointer(link->conf->chanctx_conf) != conf)
                        continue;
-               for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-                       struct ieee80211_link_data *link;
-
-                       link = rcu_dereference(sdata->link[link_id]);
-                       if (!link)
-                               continue;
-
-                       if (rcu_access_pointer(link->conf->chanctx_conf) != conf)
-                               continue;
-                       if (!link->radar_required)
-                               continue;
-                       required = true;
-                       break;
-               }
-
-               if (required)
-                       break;
+               if (!link->radar_required)
+                       continue;
+               return true;
        }
-       rcu_read_unlock();
 
-       return required;
+       return false;
 }
 
 static struct ieee80211_chanctx *
@@ -746,50 +683,38 @@ void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
                                       struct ieee80211_chanctx *ctx)
 {
        struct ieee80211_chanctx_conf *conf = &ctx->conf;
-       struct ieee80211_sub_if_data *sdata;
        const struct cfg80211_chan_def *compat = NULL;
+       struct ieee80211_link_data *link;
        struct ieee80211_chan_req chanreq = {};
        struct sta_info *sta;
 
        lockdep_assert_wiphy(local->hw.wiphy);
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-               int link_id;
+       for_each_sdata_link(local, link) {
+               struct ieee80211_bss_conf *link_conf;
 
-               if (!ieee80211_sdata_running(sdata))
+               if (link->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                        continue;
 
-               if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
-                       continue;
-
-               for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-                       struct ieee80211_bss_conf *link_conf =
-                               rcu_dereference(sdata->vif.link_conf[link_id]);
+               link_conf = link->conf;
 
-                       if (!link_conf)
-                               continue;
-
-                       if (rcu_access_pointer(link_conf->chanctx_conf) != conf)
-                               continue;
+               if (rcu_access_pointer(link_conf->chanctx_conf) != conf)
+                       continue;
 
-                       if (!compat)
-                               compat = &link_conf->chanreq.oper;
+               if (!compat)
+                       compat = &link_conf->chanreq.oper;
 
-                       compat = cfg80211_chandef_compatible(&link_conf->chanreq.oper,
-                                                            compat);
-                       if (WARN_ON_ONCE(!compat))
-                               break;
-               }
+               compat = cfg80211_chandef_compatible(&link_conf->chanreq.oper,
+                                                    compat);
+               if (WARN_ON_ONCE(!compat))
+                       return;
        }
 
-       if (WARN_ON_ONCE(!compat)) {
-               rcu_read_unlock();
+       if (WARN_ON_ONCE(!compat))
                return;
-       }
 
        /* TDLS peers can sometimes affect the chandef width */
-       list_for_each_entry_rcu(sta, &local->sta_list, list) {
+       list_for_each_entry(sta, &local->sta_list, list) {
                if (!sta->uploaded ||
                    !test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW) ||
                    !test_sta_flag(sta, WLAN_STA_AUTHORIZED) ||
@@ -799,9 +724,8 @@ void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
                compat = cfg80211_chandef_compatible(&sta->tdls_chandef,
                                                     compat);
                if (WARN_ON_ONCE(!compat))
-                       break;
+                       return;
        }
-       rcu_read_unlock();
 
        if (!compat)
                return;
@@ -895,23 +819,19 @@ void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 {
        struct ieee80211_sub_if_data *sdata;
        u8 rx_chains_static, rx_chains_dynamic;
+       struct ieee80211_link_data *link;
 
        lockdep_assert_wiphy(local->hw.wiphy);
 
        rx_chains_static = 1;
        rx_chains_dynamic = 1;
 
-       rcu_read_lock();
-       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+       for_each_sdata_link(local, link) {
                u8 needed_static, needed_dynamic;
-               unsigned int link_id;
-
-               if (!ieee80211_sdata_running(sdata))
-                       continue;
 
-               switch (sdata->vif.type) {
+               switch (link->sdata->vif.type) {
                case NL80211_IFTYPE_STATION:
-                       if (!sdata->u.mgd.associated)
+                       if (!link->sdata->u.mgd.associated)
                                continue;
                        break;
                case NL80211_IFTYPE_AP:
@@ -923,49 +843,38 @@ void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
                        continue;
                }
 
-               for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-                       struct ieee80211_link_data *link;
-
-                       link = rcu_dereference(sdata->link[link_id]);
-
-                       if (!link)
-                               continue;
-
-                       if (rcu_access_pointer(link->conf->chanctx_conf) != &chanctx->conf)
-                               continue;
-
-                       switch (link->smps_mode) {
-                       default:
-                               WARN_ONCE(1, "Invalid SMPS mode %d\n",
-                                         link->smps_mode);
-                               fallthrough;
-                       case IEEE80211_SMPS_OFF:
-                               needed_static = link->needed_rx_chains;
-                               needed_dynamic = link->needed_rx_chains;
-                               break;
-                       case IEEE80211_SMPS_DYNAMIC:
-                               needed_static = 1;
-                               needed_dynamic = link->needed_rx_chains;
-                               break;
-                       case IEEE80211_SMPS_STATIC:
-                               needed_static = 1;
-                               needed_dynamic = 1;
-                               break;
-                       }
+               if (rcu_access_pointer(link->conf->chanctx_conf) != &chanctx->conf)
+                       continue;
 
-                       rx_chains_static = max(rx_chains_static, needed_static);
-                       rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
+               switch (link->smps_mode) {
+               default:
+                       WARN_ONCE(1, "Invalid SMPS mode %d\n",
+                                 link->smps_mode);
+                       fallthrough;
+               case IEEE80211_SMPS_OFF:
+                       needed_static = link->needed_rx_chains;
+                       needed_dynamic = link->needed_rx_chains;
+                       break;
+               case IEEE80211_SMPS_DYNAMIC:
+                       needed_static = 1;
+                       needed_dynamic = link->needed_rx_chains;
+                       break;
+               case IEEE80211_SMPS_STATIC:
+                       needed_static = 1;
+                       needed_dynamic = 1;
+                       break;
                }
+
+               rx_chains_static = max(rx_chains_static, needed_static);
+               rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
        }
 
        /* Disable SMPS for the monitor interface */
-       sdata = rcu_dereference(local->monitor_sdata);
+       sdata = wiphy_dereference(local->hw.wiphy, local->monitor_sdata);
        if (sdata &&
            rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &chanctx->conf)
                rx_chains_dynamic = rx_chains_static = local->rx_chains;
 
-       rcu_read_unlock();
-
        if (rx_chains_static == chanctx->conf.rx_chains_static &&
            rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
                return;
@@ -1004,17 +913,16 @@ __ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
        if (clear)
                conf = NULL;
 
-       rcu_read_lock();
        list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
                struct ieee80211_bss_conf *vlan_conf;
 
-               vlan_conf = rcu_dereference(vlan->vif.link_conf[link_id]);
+               vlan_conf = wiphy_dereference(local->hw.wiphy,
+                                             vlan->vif.link_conf[link_id]);
                if (WARN_ON(!vlan_conf))
                        continue;
 
                rcu_assign_pointer(vlan_conf->chanctx_conf, conf);
        }
-       rcu_read_unlock();
 }
 
 void ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
@@ -1204,17 +1112,16 @@ ieee80211_link_update_chanreq(struct ieee80211_link_data *link,
        if (sdata->vif.type != NL80211_IFTYPE_AP)
                return;
 
-       rcu_read_lock();
        list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
                struct ieee80211_bss_conf *vlan_conf;
 
-               vlan_conf = rcu_dereference(vlan->vif.link_conf[link_id]);
+               vlan_conf = wiphy_dereference(sdata->local->hw.wiphy,
+                                             vlan->vif.link_conf[link_id]);
                if (WARN_ON(!vlan_conf))
                        continue;
 
                vlan_conf->chanreq = *chanreq;
        }
-       rcu_read_unlock();
 }
 
 static int
@@ -1955,12 +1862,11 @@ void ieee80211_link_vlan_copy_chanctx(struct ieee80211_link_data *link)
 
        ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
 
-       rcu_read_lock();
-       ap_conf = rcu_dereference(ap->vif.link_conf[link_id]);
-       conf = rcu_dereference_protected(ap_conf->chanctx_conf,
-                                        lockdep_is_held(&local->hw.wiphy->mtx));
+       ap_conf = wiphy_dereference(local->hw.wiphy,
+                                   ap->vif.link_conf[link_id]);
+       conf = wiphy_dereference(local->hw.wiphy,
+                                ap_conf->chanctx_conf);
        rcu_assign_pointer(link_conf->chanctx_conf, conf);
-       rcu_read_unlock();
 }
 
 void ieee80211_iter_chan_contexts_atomic(

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 70c48cad180aa08be2e30b2207645b5bea816637..601b889b6237e855ff6489354ad4bab44beb0dbe 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1181,6 +1181,19 @@ struct ieee80211_sub_if_data *vif_to_sdata(struct ieee80211_vif *p)
 #define sdata_dereference(p, sdata) \
        wiphy_dereference(sdata->local->hw.wiphy, p)
 
+#define for_each_sdata_link(_local, _link)                             \
+       /* outer loop just to define the variables ... */               \
+       for (struct ieee80211_sub_if_data *___sdata = NULL;             \
+            !___sdata;                                                 \
+            ___sdata = (void *)~0 /* always stop */)                   \
+       list_for_each_entry(___sdata, &(_local)->interfaces, list)      \
+       if (ieee80211_sdata_running(___sdata))                          \
+       for (int ___link_id = 0;                                        \
+            ___link_id < ARRAY_SIZE(___sdata->link);                   \
+            ___link_id++)                                              \
+       if ((_link = wiphy_dereference((local)->hw.wiphy,               \
+                                      ___sdata->link[___link_id])))
+
 static inline int
 ieee80211_get_mbssid_beacon_len(struct cfg80211_mbssid_elems *elems,
                                struct cfg80211_rnr_elems *rnr_elems,