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mac80211: support runtime interface type changes
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Add support to mac80211 for changing the interface
type even when the interface is UP, if the driver
supports it.

To achieve this
 * add a new driver callback for switching,
 * split some of the interface up/down code out
   into new functions (do_open/do_stop), and
 * maintain an own __SDATA_RUNNING bit that will
   not be set during interface type, so that any
   other code doesn't use the interface.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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@jmberg-intel @linvjw
jmberg-intel authored and linvjw committed Aug 27, 2010
1 parent 87490f6 commit 34d4bc4
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Showing 6 changed files with 185 additions and 37 deletions.
9 changes: 9 additions & 0 deletions include/net/mac80211.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1537,6 +1537,12 @@ enum ieee80211_ampdu_mlme_action {
* negative error code (which will be seen in userspace.)
* Must be implemented and can sleep.
*
* @change_interface: Called when a netdevice changes type. This callback
* is optional, but only if it is supported can interface types be
* switched while the interface is UP. The callback may sleep.
* Note that while an interface is being switched, it will not be
* found by the interface iteration callbacks.
*
* @remove_interface: Notifies a driver that an interface is going down.
* The @stop callback is called after this if it is the last interface
* and no monitor interfaces are present.
Expand Down Expand Up @@ -1693,6 +1699,9 @@ struct ieee80211_ops {
void (*stop)(struct ieee80211_hw *hw);
int (*add_interface)(struct ieee80211_hw *hw,
struct ieee80211_vif *vif);
int (*change_interface)(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
enum nl80211_iftype new_type);
void (*remove_interface)(struct ieee80211_hw *hw,
struct ieee80211_vif *vif);
int (*config)(struct ieee80211_hw *hw, u32 changed);
Expand Down
3 changes: 0 additions & 3 deletions net/mac80211/cfg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,9 +52,6 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
int ret;

if (ieee80211_sdata_running(sdata))
return -EBUSY;

ret = ieee80211_if_change_type(sdata, type);
if (ret)
return ret;
Expand Down
14 changes: 14 additions & 0 deletions net/mac80211/driver-ops.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,20 @@ static inline int drv_add_interface(struct ieee80211_local *local,
return ret;
}

static inline int drv_change_interface(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
enum nl80211_iftype type)
{
int ret;

might_sleep();

trace_drv_change_interface(local, sdata, type);
ret = local->ops->change_interface(&local->hw, &sdata->vif, type);
trace_drv_return_int(local, ret);
return ret;
}

static inline void drv_remove_interface(struct ieee80211_local *local,
struct ieee80211_vif *vif)
{
Expand Down
25 changes: 25 additions & 0 deletions net/mac80211/driver-trace.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,31 @@ TRACE_EVENT(drv_add_interface,
)
);

TRACE_EVENT(drv_change_interface,
TP_PROTO(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
enum nl80211_iftype type),

TP_ARGS(local, sdata, type),

TP_STRUCT__entry(
LOCAL_ENTRY
VIF_ENTRY
__field(u32, new_type)
),

TP_fast_assign(
LOCAL_ASSIGN;
VIF_ASSIGN;
__entry->new_type = type;
),

TP_printk(
LOCAL_PR_FMT VIF_PR_FMT " new type:%d",
LOCAL_PR_ARG, VIF_PR_ARG, __entry->new_type
)
);

TRACE_EVENT(drv_remove_interface,
TP_PROTO(struct ieee80211_local *local, struct ieee80211_sub_if_data *sdata),

Expand Down
14 changes: 13 additions & 1 deletion net/mac80211/ieee80211_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -472,6 +472,16 @@ enum ieee80211_sub_if_data_flags {
IEEE80211_SDATA_DONT_BRIDGE_PACKETS = BIT(3),
};

/**
* enum ieee80211_sdata_state_bits - virtual interface state bits
* @SDATA_STATE_RUNNING: virtual interface is up & running; this
* mirrors netif_running() but is separate for interface type
* change handling while the interface is up
*/
enum ieee80211_sdata_state_bits {
SDATA_STATE_RUNNING,
};

struct ieee80211_sub_if_data {
struct list_head list;

Expand All @@ -485,6 +495,8 @@ struct ieee80211_sub_if_data {

unsigned int flags;

unsigned long state;

int drop_unencrypted;

char name[IFNAMSIZ];
Expand Down Expand Up @@ -1087,7 +1099,7 @@ void ieee80211_recalc_idle(struct ieee80211_local *local);

static inline bool ieee80211_sdata_running(struct ieee80211_sub_if_data *sdata)
{
return netif_running(sdata->dev);
return test_bit(SDATA_STATE_RUNNING, &sdata->state);
}

/* tx handling */
Expand Down
157 changes: 124 additions & 33 deletions net/mac80211/iface.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -148,7 +148,12 @@ static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
return 0;
}

static int ieee80211_open(struct net_device *dev)
/*
* NOTE: Be very careful when changing this function, it must NOT return
* an error on interface type changes that have been pre-checked, so most
* checks should be in ieee80211_check_concurrent_iface.
*/
static int ieee80211_do_open(struct net_device *dev, bool coming_up)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_local *local = sdata->local;
Expand All @@ -157,15 +162,6 @@ static int ieee80211_open(struct net_device *dev)
int res;
u32 hw_reconf_flags = 0;

/* fail early if user set an invalid address */
if (!is_zero_ether_addr(dev->dev_addr) &&
!is_valid_ether_addr(dev->dev_addr))
return -EADDRNOTAVAIL;

res = ieee80211_check_concurrent_iface(sdata, sdata->vif.type);
if (res)
return res;

switch (sdata->vif.type) {
case NL80211_IFTYPE_WDS:
if (!is_valid_ether_addr(sdata->u.wds.remote_addr))
Expand Down Expand Up @@ -258,9 +254,11 @@ static int ieee80211_open(struct net_device *dev)
netif_carrier_on(dev);
break;
default:
res = drv_add_interface(local, &sdata->vif);
if (res)
goto err_stop;
if (coming_up) {
res = drv_add_interface(local, &sdata->vif);
if (res)
goto err_stop;
}

if (ieee80211_vif_is_mesh(&sdata->vif)) {
local->fif_other_bss++;
Expand Down Expand Up @@ -316,7 +314,9 @@ static int ieee80211_open(struct net_device *dev)
hw_reconf_flags |= __ieee80211_recalc_idle(local);
mutex_unlock(&local->mtx);

local->open_count++;
if (coming_up)
local->open_count++;

if (hw_reconf_flags) {
ieee80211_hw_config(local, hw_reconf_flags);
/*
Expand All @@ -331,6 +331,8 @@ static int ieee80211_open(struct net_device *dev)

netif_tx_start_all_queues(dev);

set_bit(SDATA_STATE_RUNNING, &sdata->state);

return 0;
err_del_interface:
drv_remove_interface(local, &sdata->vif);
Expand All @@ -344,19 +346,38 @@ static int ieee80211_open(struct net_device *dev)
return res;
}

static int ieee80211_stop(struct net_device *dev)
static int ieee80211_open(struct net_device *dev)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
int err;

/* fail early if user set an invalid address */
if (!is_zero_ether_addr(dev->dev_addr) &&
!is_valid_ether_addr(dev->dev_addr))
return -EADDRNOTAVAIL;

err = ieee80211_check_concurrent_iface(sdata, sdata->vif.type);
if (err)
return err;

return ieee80211_do_open(dev, true);
}

static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
bool going_down)
{
struct ieee80211_local *local = sdata->local;
unsigned long flags;
struct sk_buff *skb, *tmp;
u32 hw_reconf_flags = 0;
int i;

clear_bit(SDATA_STATE_RUNNING, &sdata->state);

/*
* Stop TX on this interface first.
*/
netif_tx_stop_all_queues(dev);
netif_tx_stop_all_queues(sdata->dev);

/*
* Purge work for this interface.
Expand Down Expand Up @@ -394,11 +415,12 @@ static int ieee80211_stop(struct net_device *dev)
if (sdata->vif.type == NL80211_IFTYPE_AP)
local->fif_pspoll--;

netif_addr_lock_bh(dev);
netif_addr_lock_bh(sdata->dev);
spin_lock_bh(&local->filter_lock);
__hw_addr_unsync(&local->mc_list, &dev->mc, dev->addr_len);
__hw_addr_unsync(&local->mc_list, &sdata->dev->mc,
sdata->dev->addr_len);
spin_unlock_bh(&local->filter_lock);
netif_addr_unlock_bh(dev);
netif_addr_unlock_bh(sdata->dev);

ieee80211_configure_filter(local);

Expand Down Expand Up @@ -432,7 +454,8 @@ static int ieee80211_stop(struct net_device *dev)
WARN_ON(!list_empty(&sdata->u.ap.vlans));
}

local->open_count--;
if (going_down)
local->open_count--;

switch (sdata->vif.type) {
case NL80211_IFTYPE_AP_VLAN:
Expand Down Expand Up @@ -504,7 +527,8 @@ static int ieee80211_stop(struct net_device *dev)
*/
ieee80211_free_keys(sdata);

drv_remove_interface(local, &sdata->vif);
if (going_down)
drv_remove_interface(local, &sdata->vif);
}

sdata->bss = NULL;
Expand Down Expand Up @@ -540,6 +564,13 @@ static int ieee80211_stop(struct net_device *dev)
}
}
spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
}

static int ieee80211_stop(struct net_device *dev)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

ieee80211_do_stop(sdata, true);

return 0;
}
Expand Down Expand Up @@ -857,9 +888,72 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
ieee80211_debugfs_add_netdev(sdata);
}

static int ieee80211_runtime_change_iftype(struct ieee80211_sub_if_data *sdata,
enum nl80211_iftype type)
{
struct ieee80211_local *local = sdata->local;
int ret, err;

ASSERT_RTNL();

if (!local->ops->change_interface)
return -EBUSY;

switch (sdata->vif.type) {
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_STATION:
case NL80211_IFTYPE_ADHOC:
/*
* Could maybe also all others here?
* Just not sure how that interacts
* with the RX/config path e.g. for
* mesh.
*/
break;
default:
return -EBUSY;
}

switch (type) {
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_STATION:
case NL80211_IFTYPE_ADHOC:
/*
* Could probably support everything
* but WDS here (WDS do_open can fail
* under memory pressure, which this
* code isn't prepared to handle).
*/
break;
default:
return -EBUSY;
}

ret = ieee80211_check_concurrent_iface(sdata, type);
if (ret)
return ret;

ieee80211_do_stop(sdata, false);

ieee80211_teardown_sdata(sdata->dev);

ret = drv_change_interface(local, sdata, type);
if (ret)
type = sdata->vif.type;

ieee80211_setup_sdata(sdata, type);

err = ieee80211_do_open(sdata->dev, false);
WARN(err, "type change: do_open returned %d", err);

return ret;
}

int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
enum nl80211_iftype type)
{
int ret;

ASSERT_RTNL();

if (type == sdata->vif.type)
Expand All @@ -870,18 +964,15 @@ int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
type == NL80211_IFTYPE_ADHOC)
return -EOPNOTSUPP;

/*
* We could, here, on changes between IBSS/STA/MESH modes,
* invoke an MLME function instead that disassociates etc.
* and goes into the requested mode.
*/

if (ieee80211_sdata_running(sdata))
return -EBUSY;

/* Purge and reset type-dependent state. */
ieee80211_teardown_sdata(sdata->dev);
ieee80211_setup_sdata(sdata, type);
if (ieee80211_sdata_running(sdata)) {
ret = ieee80211_runtime_change_iftype(sdata, type);
if (ret)
return ret;
} else {
/* Purge and reset type-dependent state. */
ieee80211_teardown_sdata(sdata->dev);
ieee80211_setup_sdata(sdata, type);
}

/* reset some values that shouldn't be kept across type changes */
sdata->vif.bss_conf.basic_rates =
Expand Down

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