From fb0e76abe34bd67756dbdf4d5982b7dc54afa1d8 Mon Sep 17 00:00:00 2001
From: Erik Stromdahl <erik.stromdahl@gmail.com>
Date: Mon, 17 Jun 2019 22:01:39 +0200
Subject: [PATCH] mac80211: add tx dequeue function for process context
Git-commit: fb0e76abe34bd67756dbdf4d5982b7dc54afa1d8
Patch-mainline: v5.4-rc1
References: jsc#SLE-13430
Since ieee80211_tx_dequeue() must not be called with softirqs enabled
(i.e. from process context without proper disable of bottom halves),
we add a wrapper that disables bottom halves before calling
ieee80211_tx_dequeue()
The new function is named ieee80211_tx_dequeue_ni() just as all other
from-process-context versions found in mac80211.
The documentation of ieee80211_tx_dequeue() is also updated so it
mentions that the function should not be called from process context.
Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
Link: https://lore.kernel.org/r/20190617200140.6189-1-erik.stromdahl@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
include/net/mac80211.h | 26 ++++++++++++++++++++++++++
net/mac80211/tx.c | 2 ++
2 files changed, 28 insertions(+)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 6cc5b25edf9d..fbe1c29e3349 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -6234,10 +6234,36 @@ void ieee80211_unreserve_tid(struct ieee80211_sta *sta, u8 tid);
* but for the duration of the frame handling.
* However, also note that while in the wake_tx_queue() method,
* rcu_read_lock() is already held.
+ *
+ * softirqs must also be disabled when this function is called.
+ * In process context, use ieee80211_tx_dequeue_ni() instead.
*/
struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
struct ieee80211_txq *txq);
+/**
+ * ieee80211_tx_dequeue_ni - dequeue a packet from a software tx queue
+ * (in process context)
+ *
+ * Like ieee80211_tx_dequeue() but can be called in process context
+ * (internally disables bottom halves).
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @txq: pointer obtained from station or virtual interface, or from
+ * ieee80211_next_txq()
+ */
+static inline struct sk_buff *ieee80211_tx_dequeue_ni(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq)
+{
+ struct sk_buff *skb;
+
+ local_bh_disable();
+ skb = ieee80211_tx_dequeue(hw, txq);
+ local_bh_enable();
+
+ return skb;
+}
+
/**
* ieee80211_next_txq - get next tx queue to pull packets from
*
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index f13eb2f61ccf..fb8870d9eba3 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3546,6 +3546,8 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
ieee80211_tx_result r;
struct ieee80211_vif *vif = txq->vif;
+ WARN_ON_ONCE(softirq_count() == 0);
+
begin:
spin_lock_bh(&fq->lock);
--
2.16.4