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Commit 5a9f7b04 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

mac80211: use separate spinlock for sta flags 



David Ellingsworth posted a bug that was only noticable on UP/NO-PREEMPT
and Michael correctly analysed it to be a spin_lock_bh() section within
a spin_lock_irqsave() section. This adds a separate spinlock for the
sta_info flags to fix that issue and avoid having to take much care
about where the sta flag manipulation functions are called.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Reported-By: default avatarDavid Ellingsworth <david@identd.dyndns.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 135a2110

net/mac80211/sta_info.c

+1 −0
Original line number Diff line number Diff line
@@ -235,6 +235,7 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata, 
		return NULL;



	spin_lock_init(&sta->lock);

	spin_lock_init(&sta->flaglock);



	memcpy(sta->addr, addr, ETH_ALEN);

	sta->local = local;

net/mac80211/sta_info.h

+27 −13
Original line number Diff line number Diff line
@@ -164,6 +164,7 @@ struct sta_ampdu_mlme { 
 * @aid: STA's unique AID (1..2007, 0 = not assigned yet),

 *	only used in AP (and IBSS?) mode

 * @flags: STA flags, see &enum ieee80211_sta_info_flags

 * @flaglock: spinlock for flags accesses

 * @ps_tx_buf: buffer of frames to transmit to this station

 *	when it leaves power saving state

 * @tx_filtered: buffer of frames we already tried to transmit
@@ -186,6 +187,7 @@ struct sta_info { 
	struct rate_control_ref *rate_ctrl;

	void *rate_ctrl_priv;

	spinlock_t lock;

	spinlock_t flaglock;

	struct ieee80211_ht_info ht_info;

	u64 supp_rates[IEEE80211_NUM_BANDS];

	u8 addr[ETH_ALEN];
@@ -198,7 +200,10 @@ struct sta_info { 
	 */

	u8 pin_status;



	/* frequently updated information, locked with lock spinlock */

	/*

	 * frequently updated, locked with own spinlock (flaglock),

	 * use the accessors defined below

	 */

	u32 flags;



	/*
@@ -293,34 +298,41 @@ static inline enum plink_state sta_plink_state(struct sta_info *sta) 


static inline void set_sta_flags(struct sta_info *sta, const u32 flags)

{

	spin_lock_bh(&sta->lock);

	unsigned long irqfl;



	spin_lock_irqsave(&sta->flaglock, irqfl);

	sta->flags |= flags;

	spin_unlock_bh(&sta->lock);

	spin_unlock_irqrestore(&sta->flaglock, irqfl);

}



static inline void clear_sta_flags(struct sta_info *sta, const u32 flags)

{

	spin_lock_bh(&sta->lock);

	unsigned long irqfl;



	spin_lock_irqsave(&sta->flaglock, irqfl);

	sta->flags &= ~flags;

	spin_unlock_bh(&sta->lock);

	spin_unlock_irqrestore(&sta->flaglock, irqfl);

}



static inline void set_and_clear_sta_flags(struct sta_info *sta,

					   const u32 set, const u32 clear)

{

	spin_lock_bh(&sta->lock);

	unsigned long irqfl;



	spin_lock_irqsave(&sta->flaglock, irqfl);

	sta->flags |= set;

	sta->flags &= ~clear;

	spin_unlock_bh(&sta->lock);

	spin_unlock_irqrestore(&sta->flaglock, irqfl);

}



static inline u32 test_sta_flags(struct sta_info *sta, const u32 flags)

{

	u32 ret;

	unsigned long irqfl;



	spin_lock_bh(&sta->lock);

	spin_lock_irqsave(&sta->flaglock, irqfl);

	ret = sta->flags & flags;

	spin_unlock_bh(&sta->lock);

	spin_unlock_irqrestore(&sta->flaglock, irqfl);



	return ret;

}
@@ -329,11 +341,12 @@ static inline u32 test_and_clear_sta_flags(struct sta_info *sta, 
					   const u32 flags)

{

	u32 ret;

	unsigned long irqfl;



	spin_lock_bh(&sta->lock);

	spin_lock_irqsave(&sta->flaglock, irqfl);

	ret = sta->flags & flags;

	sta->flags &= ~flags;

	spin_unlock_bh(&sta->lock);

	spin_unlock_irqrestore(&sta->flaglock, irqfl);



	return ret;

}
@@ -341,10 +354,11 @@ static inline u32 test_and_clear_sta_flags(struct sta_info *sta, 
static inline u32 get_sta_flags(struct sta_info *sta)

{

	u32 ret;

	unsigned long irqfl;



	spin_lock_bh(&sta->lock);

	spin_lock_irqsave(&sta->flaglock, irqfl);

	ret = sta->flags;

	spin_unlock_bh(&sta->lock);

	spin_unlock_irqrestore(&sta->flaglock, irqfl);



	return ret;

}