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remarkable-linux/net/mac80211/chan.c
Johannes Berg 34a3740d6b mac80211: fix iflist_mtx/mtx locking in radar detection 
The scan code creates an iflist_mtx -> mtx locking dependency,
and a few other places, notably radar detection, were creating
the opposite dependency, causing lockdep to complain. As scan
and radar detection are mutually exclusive, the deadlock can't
really happen in practice, but it's still bad form.

A similar issue exists in the monitor mode code, but this is
only used by channel-context drivers right now and those have
to have hardware scan, so that also can't happen.

Still, fix these issues by making some of the channel context
code require the mtx to be held rather than acquiring it, thus
allowing the monitor/radar callers to keep the iflist_mtx->mtx
lock ordering.

While at it, also fix access to the local->scanning variable
in the radar code, and document that radar_detect_enabled is
now properly protected by the mtx.

All this would now introduce an ABBA deadlock between the DFS
work cancelling and local->mtx, so change the locking there a
bit to not need to use cancel_delayed_work_sync() but be able
to just use cancel_delayed_work(). The work is also safely
stopped/removed when the interface is stopped, so no extra
changes are needed.

Reported-by: Kalle Valo <kvalo@qca.qualcomm.com>
Tested-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2013-12-19 13:33:33 +01:00

734 lines
19 KiB
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Raw Blame History

/*
* mac80211 - channel management
*/
#include <linux/nl80211.h>
#include <linux/export.h>
#include <linux/rtnetlink.h>
#include <net/cfg80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
static enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
{
switch (sta->bandwidth) {
case IEEE80211_STA_RX_BW_20:
if (sta->ht_cap.ht_supported)
return NL80211_CHAN_WIDTH_20;
else
return NL80211_CHAN_WIDTH_20_NOHT;
case IEEE80211_STA_RX_BW_40:
return NL80211_CHAN_WIDTH_40;
case IEEE80211_STA_RX_BW_80:
return NL80211_CHAN_WIDTH_80;
case IEEE80211_STA_RX_BW_160:
/*
* This applied for both 160 and 80+80. since we use
* the returned value to consider degradation of
* ctx->conf.min_def, we have to make sure to take
* the bigger one (NL80211_CHAN_WIDTH_160).
* Otherwise we might try degrading even when not
* needed, as the max required sta_bw returned (80+80)
* might be smaller than the configured bw (160).
*/
return NL80211_CHAN_WIDTH_160;
default:
WARN_ON(1);
return NL80211_CHAN_WIDTH_20;
}
}
static enum nl80211_chan_width
ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata)
{
enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
struct sta_info *sta;
rcu_read_lock();
list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
if (sdata != sta->sdata &&
!(sta->sdata->bss && sta->sdata->bss == sdata->bss))
continue;
if (!sta->uploaded)
continue;
max_bw = max(max_bw, ieee80211_get_sta_bw(&sta->sta));
}
rcu_read_unlock();
return max_bw;
}
static enum nl80211_chan_width
ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
struct ieee80211_chanctx_conf *conf)
{
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) {
struct ieee80211_vif *vif = &sdata->vif;
enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
if (!ieee80211_sdata_running(sdata))
continue;
if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
continue;
switch (vif->type) {
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_AP_VLAN:
width = ieee80211_get_max_required_bw(sdata);
break;
case NL80211_IFTYPE_P2P_DEVICE:
continue;
case NL80211_IFTYPE_STATION:
case NL80211_IFTYPE_ADHOC:
case NL80211_IFTYPE_WDS:
case NL80211_IFTYPE_MESH_POINT:
width = vif->bss_conf.chandef.width;
break;
case NL80211_IFTYPE_UNSPECIFIED:
case NUM_NL80211_IFTYPES:
case NL80211_IFTYPE_MONITOR:
case NL80211_IFTYPE_P2P_CLIENT:
case NL80211_IFTYPE_P2P_GO:
WARN_ON_ONCE(1);
}
max_bw = max(max_bw, width);
}
rcu_read_unlock();
return max_bw;
}
/*
* recalc the min required chan width of the channel context, which is
* the max of min required widths of all the interfaces bound to this
* channel context.
*/
void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx)
{
enum nl80211_chan_width max_bw;
struct cfg80211_chan_def min_def;
lockdep_assert_held(&local->chanctx_mtx);
/* don't optimize 5MHz, 10MHz, and radar_enabled confs */
if (ctx->conf.def.width == NL80211_CHAN_WIDTH_5 ||
ctx->conf.def.width == NL80211_CHAN_WIDTH_10 ||
ctx->conf.radar_enabled) {
ctx->conf.min_def = ctx->conf.def;
return;
}
max_bw = ieee80211_get_chanctx_max_required_bw(local, &ctx->conf);
/* downgrade chandef up to max_bw */
min_def = ctx->conf.def;
while (min_def.width > max_bw)
ieee80211_chandef_downgrade(&min_def);
if (cfg80211_chandef_identical(&ctx->conf.min_def, &min_def))
return;
ctx->conf.min_def = min_def;
if (!ctx->driver_present)
return;
drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_MIN_WIDTH);
}
static void ieee80211_change_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx,
const struct cfg80211_chan_def *chandef)
{
if (cfg80211_chandef_identical(&ctx->conf.def, chandef))
return;
WARN_ON(!cfg80211_chandef_compatible(&ctx->conf.def, chandef));
ctx->conf.def = *chandef;
drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_WIDTH);
ieee80211_recalc_chanctx_min_def(local, ctx);
if (!local->use_chanctx) {
local->_oper_chandef = *chandef;
ieee80211_hw_config(local, 0);
}
}
static struct ieee80211_chanctx *
ieee80211_find_chanctx(struct ieee80211_local *local,
const struct cfg80211_chan_def *chandef,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_chanctx *ctx;
lockdep_assert_held(&local->chanctx_mtx);
if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
return NULL;
list_for_each_entry(ctx, &local->chanctx_list, list) {
const struct cfg80211_chan_def *compat;
if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
continue;
compat = cfg80211_chandef_compatible(&ctx->conf.def, chandef);
if (!compat)
continue;
ieee80211_change_chanctx(local, ctx, compat);
return ctx;
}
return NULL;
}
static bool ieee80211_is_radar_required(struct ieee80211_local *local)
{
struct ieee80211_sub_if_data *sdata;
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (sdata->radar_required) {
rcu_read_unlock();
return true;
}
}
rcu_read_unlock();
return false;
}
static struct ieee80211_chanctx *
ieee80211_new_chanctx(struct ieee80211_local *local,
const struct cfg80211_chan_def *chandef,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_chanctx *ctx;
u32 changed;
int err;
lockdep_assert_held(&local->chanctx_mtx);
ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->conf.def = *chandef;
ctx->conf.rx_chains_static = 1;
ctx->conf.rx_chains_dynamic = 1;
ctx->mode = mode;
ctx->conf.radar_enabled = ieee80211_is_radar_required(local);
ieee80211_recalc_chanctx_min_def(local, ctx);
if (!local->use_chanctx)
local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
/* we hold the mutex to prevent idle from changing */
lockdep_assert_held(&local->mtx);
/* turn idle off *before* setting channel -- some drivers need that */
changed = ieee80211_idle_off(local);
if (changed)
ieee80211_hw_config(local, changed);
if (!local->use_chanctx) {
local->_oper_chandef = *chandef;
ieee80211_hw_config(local, 0);
} else {
err = drv_add_chanctx(local, ctx);
if (err) {
kfree(ctx);
ieee80211_recalc_idle(local);
return ERR_PTR(err);
}
}
/* and keep the mutex held until the new chanctx is on the list */
list_add_rcu(&ctx->list, &local->chanctx_list);
return ctx;
}
static void ieee80211_free_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *ctx)
{
bool check_single_channel = false;
lockdep_assert_held(&local->chanctx_mtx);
WARN_ON_ONCE(ctx->refcount != 0);
if (!local->use_chanctx) {
struct cfg80211_chan_def *chandef = &local->_oper_chandef;
chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
chandef->center_freq1 = chandef->chan->center_freq;
chandef->center_freq2 = 0;
/* NOTE: Disabling radar is only valid here for
* single channel context. To be sure, check it ...
*/
if (local->hw.conf.radar_enabled)
check_single_channel = true;
local->hw.conf.radar_enabled = false;
ieee80211_hw_config(local, 0);
} else {
drv_remove_chanctx(local, ctx);
}
list_del_rcu(&ctx->list);
kfree_rcu(ctx, rcu_head);
/* throw a warning if this wasn't the only channel context. */
WARN_ON(check_single_channel && !list_empty(&local->chanctx_list));
ieee80211_recalc_idle(local);
}
static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
struct ieee80211_chanctx *ctx)
{
struct ieee80211_local *local = sdata->local;
int ret;
lockdep_assert_held(&local->chanctx_mtx);
ret = drv_assign_vif_chanctx(local, sdata, ctx);
if (ret)
return ret;
rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
ctx->refcount++;
ieee80211_recalc_txpower(sdata);
ieee80211_recalc_chanctx_min_def(local, ctx);
sdata->vif.bss_conf.idle = false;
if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
sdata->vif.type != NL80211_IFTYPE_MONITOR)
ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
return 0;
}
static 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;
lockdep_assert_held(&local->chanctx_mtx);
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
continue;
if (!compat)
compat = &sdata->vif.bss_conf.chandef;
compat = cfg80211_chandef_compatible(
&sdata->vif.bss_conf.chandef, compat);
if (!compat)
break;
}
rcu_read_unlock();
if (WARN_ON_ONCE(!compat))
return;
ieee80211_change_chanctx(local, ctx, compat);
}
static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *chanctx)
{
bool radar_enabled;
lockdep_assert_held(&local->chanctx_mtx);
/* for setting local->radar_detect_enabled */
lockdep_assert_held(&local->mtx);
radar_enabled = ieee80211_is_radar_required(local);
if (radar_enabled == chanctx->conf.radar_enabled)
return;
chanctx->conf.radar_enabled = radar_enabled;
local->radar_detect_enabled = chanctx->conf.radar_enabled;
if (!local->use_chanctx) {
local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
}
drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
}
static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
struct ieee80211_chanctx *ctx)
{
struct ieee80211_local *local = sdata->local;
lockdep_assert_held(&local->chanctx_mtx);
ctx->refcount--;
rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
sdata->vif.bss_conf.idle = true;
if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
sdata->vif.type != NL80211_IFTYPE_MONITOR)
ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
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);
}
}
static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx_conf *conf;
struct ieee80211_chanctx *ctx;
lockdep_assert_held(&local->chanctx_mtx);
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf)
return;
ctx = container_of(conf, struct ieee80211_chanctx, conf);
ieee80211_unassign_vif_chanctx(sdata, ctx);
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
}
void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
struct ieee80211_chanctx *chanctx)
{
struct ieee80211_sub_if_data *sdata;
u8 rx_chains_static, rx_chains_dynamic;
lockdep_assert_held(&local->chanctx_mtx);
rx_chains_static = 1;
rx_chains_dynamic = 1;
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
u8 needed_static, needed_dynamic;
if (!ieee80211_sdata_running(sdata))
continue;
if (rcu_access_pointer(sdata->vif.chanctx_conf) !=
&chanctx->conf)
continue;
switch (sdata->vif.type) {
case NL80211_IFTYPE_P2P_DEVICE:
continue;
case NL80211_IFTYPE_STATION:
if (!sdata->u.mgd.associated)
continue;
break;
case NL80211_IFTYPE_AP_VLAN:
continue;
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_ADHOC:
case NL80211_IFTYPE_WDS:
case NL80211_IFTYPE_MESH_POINT:
break;
default:
WARN_ON_ONCE(1);
}
switch (sdata->smps_mode) {
default:
WARN_ONCE(1, "Invalid SMPS mode %d\n",
sdata->smps_mode);
/* fall through */
case IEEE80211_SMPS_OFF:
needed_static = sdata->needed_rx_chains;
needed_dynamic = sdata->needed_rx_chains;
break;
case IEEE80211_SMPS_DYNAMIC:
needed_static = 1;
needed_dynamic = sdata->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);
}
rcu_read_unlock();
if (!local->use_chanctx) {
if (rx_chains_static > 1)
local->smps_mode = IEEE80211_SMPS_OFF;
else if (rx_chains_dynamic > 1)
local->smps_mode = IEEE80211_SMPS_DYNAMIC;
else
local->smps_mode = IEEE80211_SMPS_STATIC;
ieee80211_hw_config(local, 0);
}
if (rx_chains_static == chanctx->conf.rx_chains_static &&
rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
return;
chanctx->conf.rx_chains_static = rx_chains_static;
chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
}
int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
enum ieee80211_chanctx_mode mode)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx *ctx;
int ret;
lockdep_assert_held(&local->mtx);
WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
mutex_lock(&local->chanctx_mtx);
__ieee80211_vif_release_channel(sdata);
ctx = ieee80211_find_chanctx(local, chandef, mode);
if (!ctx)
ctx = ieee80211_new_chanctx(local, chandef, mode);
if (IS_ERR(ctx)) {
ret = PTR_ERR(ctx);
goto out;
}
sdata->vif.bss_conf.chandef = *chandef;
ret = ieee80211_assign_vif_chanctx(sdata, ctx);
if (ret) {
/* if assign fails refcount stays the same */
if (ctx->refcount == 0)
ieee80211_free_chanctx(local, ctx);
goto out;
}
ieee80211_recalc_smps_chanctx(local, ctx);
ieee80211_recalc_radar_chanctx(local, ctx);
out:
mutex_unlock(&local->chanctx_mtx);
return ret;
}
int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
u32 *changed)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx_conf *conf;
struct ieee80211_chanctx *ctx;
const struct cfg80211_chan_def *chandef = &sdata->csa_chandef;
int ret;
u32 chanctx_changed = 0;
lockdep_assert_held(&local->mtx);
/* should never be called if not performing a channel switch. */
if (WARN_ON(!sdata->vif.csa_active))
return -EINVAL;
if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
IEEE80211_CHAN_DISABLED))
return -EINVAL;
mutex_lock(&local->chanctx_mtx);
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf) {
ret = -EINVAL;
goto out;
}
ctx = container_of(conf, struct ieee80211_chanctx, conf);
if (ctx->refcount != 1) {
ret = -EINVAL;
goto out;
}
if (sdata->vif.bss_conf.chandef.width != chandef->width) {
chanctx_changed = IEEE80211_CHANCTX_CHANGE_WIDTH;
*changed |= BSS_CHANGED_BANDWIDTH;
}
sdata->vif.bss_conf.chandef = *chandef;
ctx->conf.def = *chandef;
chanctx_changed |= IEEE80211_CHANCTX_CHANGE_CHANNEL;
drv_change_chanctx(local, ctx, chanctx_changed);
ieee80211_recalc_chanctx_chantype(local, ctx);
ieee80211_recalc_smps_chanctx(local, ctx);
ieee80211_recalc_radar_chanctx(local, ctx);
ieee80211_recalc_chanctx_min_def(local, ctx);
ret = 0;
out:
mutex_unlock(&local->chanctx_mtx);
return ret;
}
int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
const struct cfg80211_chan_def *chandef,
u32 *changed)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_chanctx_conf *conf;
struct ieee80211_chanctx *ctx;
int ret;
if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
IEEE80211_CHAN_DISABLED))
return -EINVAL;
mutex_lock(&local->chanctx_mtx);
if (cfg80211_chandef_identical(chandef, &sdata->vif.bss_conf.chandef)) {
ret = 0;
goto out;
}
if (chandef->width == NL80211_CHAN_WIDTH_20_NOHT ||
sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT) {
ret = -EINVAL;
goto out;
}
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
if (!conf) {
ret = -EINVAL;
goto out;
}
ctx = container_of(conf, struct ieee80211_chanctx, conf);
if (!cfg80211_chandef_compatible(&conf->def, chandef)) {
ret = -EINVAL;
goto out;
}
sdata->vif.bss_conf.chandef = *chandef;
ieee80211_recalc_chanctx_chantype(local, ctx);
*changed |= BSS_CHANGED_BANDWIDTH;
ret = 0;
out:
mutex_unlock(&local->chanctx_mtx);
return ret;
}
void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
{
WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
lockdep_assert_held(&sdata->local->mtx);
mutex_lock(&sdata->local->chanctx_mtx);
__ieee80211_vif_release_channel(sdata);
mutex_unlock(&sdata->local->chanctx_mtx);
}
void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_sub_if_data *ap;
struct ieee80211_chanctx_conf *conf;
if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
return;
ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
mutex_lock(&local->chanctx_mtx);
conf = rcu_dereference_protected(ap->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
mutex_unlock(&local->chanctx_mtx);
}
void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
bool clear)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_sub_if_data *vlan;
struct ieee80211_chanctx_conf *conf;
ASSERT_RTNL();
if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
return;
mutex_lock(&local->chanctx_mtx);
/*
* Check that conf exists, even when clearing this function
* must be called with the AP's channel context still there
* as it would otherwise cause VLANs to have an invalid
* channel context pointer for a while, possibly pointing
* to a channel context that has already been freed.
*/
conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
lockdep_is_held(&local->chanctx_mtx));
WARN_ON(!conf);
if (clear)
conf = NULL;
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
mutex_unlock(&local->chanctx_mtx);
}
void ieee80211_iter_chan_contexts_atomic(
struct ieee80211_hw *hw,
void (*iter)(struct ieee80211_hw *hw,
struct ieee80211_chanctx_conf *chanctx_conf,
void *data),
void *iter_data)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_chanctx *ctx;
rcu_read_lock();
list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
if (ctx->driver_present)
iter(hw, &ctx->conf, iter_data);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);
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