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mac80211: station state transition error handling
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In the future, when we start notifying drivers,
state transitions could potentially fail. To make
it easier to distinguish between programming bugs
and driver failures:
 * rename sta_info_move_state() to
   sta_info_pre_move_state() which can only be
   called before the station is inserted (and
   check this with a new station flag).
 * rename sta_info_move_state_checked() to just
   plain sta_info_move_state(), as it will be
   the regular function that can fail for more
   than just one reason (bad transition or an
   error from the driver)

This makes the programming model easier -- one of
the functions can only be called before insertion
and can't fail, the other can fail.

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 Jan 30, 2012
1 parent c037b83 commit 83d5cc0
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Showing 8 changed files with 59 additions and 39 deletions.
22 changes: 8 additions & 14 deletions net/mac80211/cfg.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -776,24 +776,20 @@ static int sta_apply_parameters(struct ieee80211_local *local,

if (set & BIT(NL80211_STA_FLAG_AUTHENTICATED) &&
!test_sta_flag(sta, WLAN_STA_AUTH)) {
ret = sta_info_move_state_checked(sta,
IEEE80211_STA_AUTH);
ret = sta_info_move_state(sta, IEEE80211_STA_AUTH);
if (ret)
return ret;
ret = sta_info_move_state_checked(sta,
IEEE80211_STA_ASSOC);
ret = sta_info_move_state(sta, IEEE80211_STA_ASSOC);
if (ret)
return ret;
}
}

if (mask & BIT(NL80211_STA_FLAG_AUTHORIZED)) {
if (set & BIT(NL80211_STA_FLAG_AUTHORIZED))
ret = sta_info_move_state_checked(sta,
IEEE80211_STA_AUTHORIZED);
ret = sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
else if (test_sta_flag(sta, WLAN_STA_AUTHORIZED))
ret = sta_info_move_state_checked(sta,
IEEE80211_STA_ASSOC);
ret = sta_info_move_state(sta, IEEE80211_STA_ASSOC);
if (ret)
return ret;
}
Expand All @@ -805,12 +801,10 @@ static int sta_apply_parameters(struct ieee80211_local *local,

if (!(set & BIT(NL80211_STA_FLAG_AUTHENTICATED)) &&
test_sta_flag(sta, WLAN_STA_AUTH)) {
ret = sta_info_move_state_checked(sta,
IEEE80211_STA_AUTH);
ret = sta_info_move_state(sta, IEEE80211_STA_AUTH);
if (ret)
return ret;
ret = sta_info_move_state_checked(sta,
IEEE80211_STA_NONE);
ret = sta_info_move_state(sta, IEEE80211_STA_NONE);
if (ret)
return ret;
}
Expand Down Expand Up @@ -944,8 +938,8 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev,
if (!sta)
return -ENOMEM;

sta_info_move_state(sta, IEEE80211_STA_AUTH);
sta_info_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);

err = sta_apply_parameters(local, sta, params);
if (err) {
Expand Down
5 changes: 3 additions & 2 deletions net/mac80211/debugfs_sta.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -63,14 +63,15 @@ static ssize_t sta_flags_read(struct file *file, char __user *userbuf,
test_sta_flag(sta, WLAN_STA_##flg) ? #flg "\n" : ""

int res = scnprintf(buf, sizeof(buf),
"%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
"%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
TEST(AUTH), TEST(ASSOC), TEST(PS_STA),
TEST(PS_DRIVER), TEST(AUTHORIZED),
TEST(SHORT_PREAMBLE),
TEST(WME), TEST(WDS), TEST(CLEAR_PS_FILT),
TEST(MFP), TEST(BLOCK_BA), TEST(PSPOLL),
TEST(UAPSD), TEST(SP), TEST(TDLS_PEER),
TEST(TDLS_PEER_AUTH));
TEST(TDLS_PEER_AUTH), TEST(4ADDR_EVENT),
TEST(INSERTED));
#undef TEST
return simple_read_from_buffer(userbuf, count, ppos, buf, res);
}
Expand Down
6 changes: 3 additions & 3 deletions net/mac80211/ibss.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -265,9 +265,9 @@ static struct sta_info *ieee80211_ibss_finish_sta(struct sta_info *sta,
addr, sdata->name);
#endif

sta_info_move_state(sta, IEEE80211_STA_AUTH);
sta_info_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);

rate_control_rate_init(sta);

Expand Down
6 changes: 3 additions & 3 deletions net/mac80211/iface.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -318,9 +318,9 @@ static int ieee80211_do_open(struct net_device *dev, bool coming_up)
goto err_del_interface;
}

sta_info_move_state(sta, IEEE80211_STA_AUTH);
sta_info_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);

res = sta_info_insert(sta);
if (res) {
Expand Down
6 changes: 3 additions & 3 deletions net/mac80211/mesh_plink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -96,9 +96,9 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
if (!sta)
return NULL;

sta_info_move_state(sta, IEEE80211_STA_AUTH);
sta_info_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);

set_sta_flag(sta, WLAN_STA_WME);

Expand Down
17 changes: 13 additions & 4 deletions net/mac80211/mlme.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1587,10 +1587,19 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
return false;
}

sta_info_move_state(sta, IEEE80211_STA_AUTH);
sta_info_move_state(sta, IEEE80211_STA_ASSOC);
if (!(ifmgd->flags & IEEE80211_STA_CONTROL_PORT))
sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
err = sta_info_move_state(sta, IEEE80211_STA_AUTH);
if (!err)
err = sta_info_move_state(sta, IEEE80211_STA_ASSOC);
if (!err && !(ifmgd->flags & IEEE80211_STA_CONTROL_PORT))
err = sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
if (err) {
printk(KERN_DEBUG
"%s: failed to move station %pM to desired state\n",
sdata->name, sta->sta.addr);
WARN_ON(__sta_info_destroy(sta));
mutex_unlock(&sdata->local->sta_mtx);
return false;
}

rates = 0;
basic_rates = 0;
Expand Down
19 changes: 14 additions & 5 deletions net/mac80211/sta_info.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -403,6 +403,8 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
sta_info_hash_add(local, sta);

list_add(&sta->list, &local->sta_list);

set_sta_flag(sta, WLAN_STA_INSERTED);
} else {
sta->dummy = false;
}
Expand Down Expand Up @@ -707,7 +709,7 @@ static bool sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
return have_buffered;
}

static int __must_check __sta_info_destroy(struct sta_info *sta)
int __must_check __sta_info_destroy(struct sta_info *sta)
{
struct ieee80211_local *local;
struct ieee80211_sub_if_data *sdata;
Expand All @@ -722,6 +724,8 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
local = sta->local;
sdata = sta->sdata;

lockdep_assert_held(&local->sta_mtx);

/*
* Before removing the station from the driver and
* rate control, it might still start new aggregation
Expand Down Expand Up @@ -763,8 +767,13 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
RCU_INIT_POINTER(sdata->u.vlan.sta, NULL);

while (sta->sta_state > IEEE80211_STA_NONE)
sta_info_move_state(sta, sta->sta_state - 1);
while (sta->sta_state > IEEE80211_STA_NONE) {
int err = sta_info_move_state(sta, sta->sta_state - 1);
if (err) {
WARN_ON_ONCE(1);
break;
}
}

if (sta->uploaded) {
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
Expand Down Expand Up @@ -1391,8 +1400,8 @@ void ieee80211_sta_set_buffered(struct ieee80211_sta *pubsta,
}
EXPORT_SYMBOL(ieee80211_sta_set_buffered);

int sta_info_move_state_checked(struct sta_info *sta,
enum ieee80211_sta_state new_state)
int sta_info_move_state(struct sta_info *sta,
enum ieee80211_sta_state new_state)
{
might_sleep();

Expand Down
17 changes: 12 additions & 5 deletions net/mac80211/sta_info.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,7 @@
* @WLAN_STA_SP: Station is in a service period, so don't try to
* reply to other uAPSD trigger frames or PS-Poll.
* @WLAN_STA_4ADDR_EVENT: 4-addr event was already sent for this frame.
* @WLAN_STA_INSERTED: This station is inserted into the hash table.
*/
enum ieee80211_sta_info_flags {
WLAN_STA_AUTH,
Expand All @@ -71,6 +72,7 @@ enum ieee80211_sta_info_flags {
WLAN_STA_UAPSD,
WLAN_STA_SP,
WLAN_STA_4ADDR_EVENT,
WLAN_STA_INSERTED,
};

enum ieee80211_sta_state {
Expand Down Expand Up @@ -427,13 +429,17 @@ static inline int test_and_set_sta_flag(struct sta_info *sta,
return test_and_set_bit(flag, &sta->_flags);
}

int sta_info_move_state_checked(struct sta_info *sta,
enum ieee80211_sta_state new_state);
int sta_info_move_state(struct sta_info *sta,
enum ieee80211_sta_state new_state);

static inline void sta_info_move_state(struct sta_info *sta,
enum ieee80211_sta_state new_state)
static inline void sta_info_pre_move_state(struct sta_info *sta,
enum ieee80211_sta_state new_state)
{
int ret = sta_info_move_state_checked(sta, new_state);
int ret;

WARN_ON_ONCE(test_sta_flag(sta, WLAN_STA_INSERTED));

ret = sta_info_move_state(sta, new_state);
WARN_ON_ONCE(ret);
}

Expand Down Expand Up @@ -544,6 +550,7 @@ int sta_info_insert(struct sta_info *sta);
int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU);
int sta_info_reinsert(struct sta_info *sta);

int __must_check __sta_info_destroy(struct sta_info *sta);
int sta_info_destroy_addr(struct ieee80211_sub_if_data *sdata,
const u8 *addr);
int sta_info_destroy_addr_bss(struct ieee80211_sub_if_data *sdata,
Expand Down

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