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Commit 296fcba3 authored by Thomas Pedersen's avatar Thomas Pedersen Committed by Johannes Berg
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mac80211: clean up mesh sta allocation warning 



This refactoring fixes a "scheduling while atomic" warning
when allocating a mesh station entry while holding the RCU
read lock. Fix this by creating a new function
mesh_sta_info_get(), which correctly handles the locking
and returns under RCU.

Also move some unnecessarily #ifdefed mesh station init
code from sta_info_alloc() to __mesh_sta_info_alloc().

Signed-off-by: default avatarThomas Pedersen <thomas@cozybit.com>
[change code flow to make sparse happy]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent d437c86b

net/mac80211/mesh_plink.c

+95 −63
Original line number Diff line number Diff line
@@ -55,30 +55,6 @@ static inline void mesh_plink_fsm_restart(struct sta_info *sta) 
	sta->plink_retries = 0;

}



/*

 * Allocate mesh sta entry and insert into station table

 */

static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,

					 u8 *hw_addr)

{

	struct sta_info *sta;



	if (sdata->local->num_sta >= MESH_MAX_PLINKS)

		return NULL;



	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);

	if (!sta)

		return NULL;



	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);



	return sta;

}



/**

 * mesh_set_ht_prot_mode - set correct HT protection mode

 *
@@ -309,52 +285,24 @@ free: 
	return err;

}



/**

 * mesh_peer_init - initialize new mesh peer and return resulting sta_info

 *

 * @sdata: local meshif

 * @addr: peer's address

 * @elems: IEs from beacon or mesh peering frame

 *

 * call under RCU

 */

static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,

				       u8 *addr,

				       struct ieee802_11_elems *elems)

static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,

			       struct sta_info *sta,

			       struct ieee802_11_elems *elems, bool insert)

{

	struct ieee80211_local *local = sdata->local;

	enum ieee80211_band band = ieee80211_get_sdata_band(sdata);

	struct ieee80211_supported_band *sband;

	u32 rates, basic_rates = 0;

	struct sta_info *sta;

	bool insert = false;



	sband = local->hw.wiphy->bands[band];

	rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);



	sta = sta_info_get(sdata, addr);

	if (!sta) {

		/* Userspace handles peer allocation when security is enabled */

		if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {

			cfg80211_notify_new_peer_candidate(sdata->dev, addr,

							   elems->ie_start,

							   elems->total_len,

							   GFP_ATOMIC);

			return NULL;

		}



		sta = mesh_plink_alloc(sdata, addr);

		if (!sta)

			return NULL;

		insert = true;

	}



	spin_lock_bh(&sta->lock);

	sta->last_rx = jiffies;

	if (sta->plink_state == NL80211_PLINK_ESTAB) {

		spin_unlock_bh(&sta->lock);

		return sta;

	}



	/* rates and capabilities don't change during peering */

	if (sta->plink_state == NL80211_PLINK_ESTAB)

		goto out;



	sta->sta.supp_rates[band] = rates;

	if (elems->ht_cap_elem &&
@@ -379,22 +327,104 @@ static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata, 


	if (insert)

		rate_control_rate_init(sta);

out:

	spin_unlock_bh(&sta->lock);

}



static struct sta_info *

__mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)

{

	struct sta_info *sta;



	if (sdata->local->num_sta >= MESH_MAX_PLINKS)

		return NULL;



	if (insert && sta_info_insert(sta))

	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);

	if (!sta)

		return NULL;



	sta->plink_state = NL80211_PLINK_LISTEN;

	init_timer(&sta->plink_timer);



	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);



	return sta;

}



static struct sta_info *

mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,

		    struct ieee802_11_elems *elems)

{

	struct sta_info *sta = NULL;



	/* Userspace handles peer allocation when security is enabled */

	if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)

		cfg80211_notify_new_peer_candidate(sdata->dev, addr,

						   elems->ie_start,

						   elems->total_len,

						   GFP_KERNEL);

	else

		sta = __mesh_sta_info_alloc(sdata, addr);



	return sta;

}



/*

 * mesh_sta_info_get - return mesh sta info entry for @addr.

 *

 * @sdata: local meshif

 * @addr: peer's address

 * @elems: IEs from beacon or mesh peering frame.

 *

 * Return existing or newly allocated sta_info under RCU read lock.

 * (re)initialize with given IEs.

 */

static struct sta_info *

mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,

		  u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)

{

	struct sta_info *sta = NULL;



	rcu_read_lock();

	sta = sta_info_get(sdata, addr);

	if (sta) {

		mesh_sta_info_init(sdata, sta, elems, false);

	} else {

		rcu_read_unlock();

		/* can't run atomic */

		sta = mesh_sta_info_alloc(sdata, addr, elems);

		if (!sta) {

			rcu_read_lock();

			return NULL;

		}



		if (sta_info_insert_rcu(sta))

			return NULL;

	}



	return sta;

}



/*

 * mesh_neighbour_update - update or initialize new mesh neighbor.

 *

 * @sdata: local meshif

 * @addr: peer's address

 * @elems: IEs from beacon or mesh peering frame

 *

 * Initiates peering if appropriate.

 */

void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,

			   u8 *hw_addr,

			   struct ieee802_11_elems *elems)

{

	struct sta_info *sta;



	rcu_read_lock();

	sta = mesh_peer_init(sdata, hw_addr, elems);

	sta = mesh_sta_info_get(sdata, hw_addr, elems);

	if (!sta)

		goto out;
@@ -632,6 +662,7 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m 
	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))

		memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);



	/* WARNING: Only for sta pointer, is dropped & re-acquired */

	rcu_read_lock();



	sta = sta_info_get(sdata, mgmt->sa);
@@ -735,8 +766,9 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m 
	}



	if (event == OPN_ACPT) {

		rcu_read_unlock();

		/* allocate sta entry if necessary and update info */

		sta = mesh_peer_init(sdata, mgmt->sa, &elems);

		sta = mesh_sta_info_get(sdata, mgmt->sa, &elems);

		if (!sta) {

			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");

			rcu_read_unlock();

net/mac80211/sta_info.c

+0 −5
Original line number Diff line number Diff line
@@ -380,11 +380,6 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata, 


	sta_dbg(sdata, "Allocated STA %pM\n", sta->sta.addr);



#ifdef CONFIG_MAC80211_MESH

	sta->plink_state = NL80211_PLINK_LISTEN;

	init_timer(&sta->plink_timer);

#endif



	return sta;

}