It doesn't make much sense to have a manually
managed chanctx refcount. It isn't performance
critical and it can't be even used outside the
protection of chanctx_mtx.
With future enhancements to channel contenxt
(namely reservations) refcount accounting will
become more complex and having manually managed
refcount is going to be error-prone and confusing.
The refcount is now equal to the number of vifs it
is assigned to. However in the future this will
change so keep the refcount/num_assigned_vifs
functions split now.
Signed-off-by: Michal Kazior <michal.kazior@xxxxxxxxx>
---
net/mac80211/cfg.c | 2 +-
net/mac80211/chan.c | 62 +++++++++++++++++++++++++++++++++++++---------
net/mac80211/ieee80211_i.h | 5 +++-
net/mac80211/mlme.c | 2 +-
4 files changed, 56 insertions(+), 15 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index a79875c..b5c9a77 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -3242,7 +3242,7 @@ int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
/* don't handle for multi-VIF cases */
chanctx = container_of(chanctx_conf, struct ieee80211_chanctx, conf);
- if (chanctx->refcount > 1) {
+ if (ieee80211_chanctx_refcount(chanctx) > 1) {
mutex_unlock(&local->chanctx_mtx);
return -EBUSY;
}
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 5b946e8..a320dfd 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -9,6 +9,45 @@
#include "ieee80211_i.h"
#include "driver-ops.h"
+struct ieee80211_chanctx *
+ieee80211_vif_assigned_chanctx(struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_local *local = sdata->local;
+ struct ieee80211_chanctx_conf *conf;
+
+ lockdep_assert_held(&local->chanctx_mtx);
+
+ conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+ lockdep_is_held(&local->chanctx_mtx));
+ if (!conf)
+ return NULL;
+
+ return container_of(conf, struct ieee80211_chanctx, conf);
+}
+
+int ieee80211_chanctx_num_assigned_vifs(struct ieee80211_chanctx *ctx)
+{
+ struct ieee80211_local *local = ctx->local;
+ struct ieee80211_sub_if_data *sdata;
+ int num = 0;
+
+ lockdep_assert_held(&local->chanctx_mtx);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(sdata, &local->interfaces, list)
+ if (ieee80211_vif_assigned_chanctx(sdata) == ctx)
+ num++;
+ rcu_read_unlock();
+
+ return num;
+}
+
+int ieee80211_chanctx_refcount(struct ieee80211_chanctx *ctx)
+{
+ lockdep_assert_held(&ctx->local->chanctx_mtx);
+ return ieee80211_chanctx_num_assigned_vifs(ctx);
+}
+
static enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
{
switch (sta->bandwidth) {
@@ -266,7 +305,7 @@ static void ieee80211_free_chanctx(struct ieee80211_local *local,
bool check_single_channel = false;
lockdep_assert_held(&local->chanctx_mtx);
- WARN_ON_ONCE(ctx->refcount != 0);
+ WARN_ON_ONCE(ieee80211_chanctx_refcount(ctx) != 0);
if (!local->use_chanctx) {
struct cfg80211_chan_def *chandef = &local->_oper_chandef;
@@ -308,7 +347,6 @@ static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
return ret;
rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
- ctx->refcount++;
ieee80211_recalc_txpower(sdata);
ieee80211_recalc_chanctx_min_def(local, ctx);
@@ -386,7 +424,6 @@ static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
lockdep_assert_held(&local->chanctx_mtx);
- ctx->refcount--;
rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
sdata->vif.bss_conf.idle = true;
@@ -397,12 +434,13 @@ static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
drv_unassign_vif_chanctx(local, sdata, ctx);
- if (ctx->refcount > 0) {
- ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
- ieee80211_recalc_smps_chanctx(local, ctx);
- ieee80211_recalc_radar_chanctx(local, ctx);
- ieee80211_recalc_chanctx_min_def(local, ctx);
- }
+ if (ieee80211_chanctx_num_assigned_vifs(ctx) == 0)
+ return;
+
+ ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
+ ieee80211_recalc_smps_chanctx(local, ctx);
+ ieee80211_recalc_radar_chanctx(local, ctx);
+ ieee80211_recalc_chanctx_min_def(local, ctx);
}
static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
@@ -421,7 +459,7 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
ctx = container_of(conf, struct ieee80211_chanctx, conf);
ieee80211_unassign_vif_chanctx(sdata, ctx);
- if (ctx->refcount == 0)
+ if (ieee80211_chanctx_refcount(ctx) == 0)
ieee80211_free_chanctx(local, ctx);
}
@@ -536,7 +574,7 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
ret = ieee80211_assign_vif_chanctx(sdata, ctx);
if (ret) {
/* if assign fails refcount stays the same */
- if (ctx->refcount == 0)
+ if (ieee80211_chanctx_refcount(ctx) == 0)
ieee80211_free_chanctx(local, ctx);
goto out;
}
@@ -577,7 +615,7 @@ int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
}
ctx = container_of(conf, struct ieee80211_chanctx, conf);
- if (ctx->refcount != 1) {
+ if (ieee80211_chanctx_refcount(ctx) != 1) {
ret = -EINVAL;
goto out;
}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index c21b0c3..11d70b5 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -693,7 +693,6 @@ struct ieee80211_chanctx {
struct ieee80211_local *local;
enum ieee80211_chanctx_mode mode;
- int refcount;
bool driver_present;
struct ieee80211_chanctx_conf conf;
@@ -1788,6 +1787,10 @@ void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata);
void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata);
void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear);
+struct ieee80211_chanctx *
+ieee80211_vif_assigned_chanctx(struct ieee80211_sub_if_data *sdata);
+int ieee80211_chanctx_num_assigned_vifs(struct ieee80211_chanctx *ctx);
+int ieee80211_chanctx_refcount(struct ieee80211_chanctx *ctx);
void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *chanctx);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 46b62bb..c0b2fb0 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1066,7 +1066,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
}
chanctx = container_of(rcu_access_pointer(sdata->vif.chanctx_conf),
struct ieee80211_chanctx, conf);
- if (chanctx->refcount > 1) {
+ if (ieee80211_chanctx_refcount(chanctx) > 1) {
sdata_info(sdata,
"channel switch with multiple interfaces on the same channel, disconnecting\n");
ieee80211_queue_work(&local->hw,
--
1.8.5.3
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