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From:   Johannes Berg <johannes@sipsolutions.net>
To:     linux-wireless@vger.kernel.org
Cc:     Johannes Berg <johannes.berg@intel.com>,
        Solomon Peachy <pizza@shaftnet.org>
Subject: [PATCH 10/12] wifi: cw1200: remove RCU STA pointer handling in TX
Date:   Sun,  4 Sep 2022 21:29:10 +0200
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From: Johannes Berg <johannes.berg@intel.com>

We can call this in one of two ways: through mac80211, where
we're already in an RCU read-side critical section, or from
some other code in the driver where this pointer can only be
NULL. In any case, we get a 'free' already protected pointer
to the sta through info->control.sta, so we can use it on
the stack without any further protection.

Remove the rcu_dereference() and critical section.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
Cc: Solomon Peachy <pizza@shaftnet.org>
---
 drivers/net/wireless/st/cw1200/txrx.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/wireless/st/cw1200/txrx.c b/drivers/net/wireless/st/cw1200/txrx.c
index fde21fca6c5e..ab19e0403dc2 100644
--- a/drivers/net/wireless/st/cw1200/txrx.c
+++ b/drivers/net/wireless/st/cw1200/txrx.c
@@ -762,8 +762,7 @@ void cw1200_tx(struct ieee80211_hw *dev,
 	if (ret)
 		goto drop;
 
-	rcu_read_lock();
-	sta = rcu_dereference(t.sta);
+	sta = t.sta;
 
 	spin_lock_bh(&priv->ps_state_lock);
 	{
@@ -776,8 +775,6 @@ void cw1200_tx(struct ieee80211_hw *dev,
 	if (tid_update && sta)
 		ieee80211_sta_set_buffered(sta, t.txpriv.tid, true);
 
-	rcu_read_unlock();
-
 	cw1200_bh_wakeup(priv);
 
 	return;
-- 
2.37.2