net: mac802154: Introduce a helper to disable the queue

Sometimes calling the stop queue helper is not enough because it does
not hold any lock. In order to be safe and avoid racy situations when
trying to (soon) sync the Tx queue, for instance before sending an MLME
frame, let's now introduce an helper which actually hold the necessary
locks when doing so.

Suggested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220519150516.443078-8-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index 0c7ff9e0b6321a2348444b5dcbe9999bc7be94dc..e34db1d49ef4343bb014ff83947876caf9f0e6d5 100644 (file)
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -149,6 +149,18 @@ void ieee802154_hold_queue(struct ieee802154_local *local);
  */
 void ieee802154_release_queue(struct ieee802154_local *local);
 
+/**
+ * ieee802154_disable_queue - disable ieee802154 queue
+ * @local: main mac object
+ *
+ * When trying to sync the Tx queue, we cannot just stop the queue
+ * (which is basically a bit being set without proper lock handling)
+ * because it would be racy. We actually need to call netif_tx_disable()
+ * instead, which is done by this helper. Restarting the queue can
+ * however still be done with a regular wake call.
+ */
+void ieee802154_disable_queue(struct ieee802154_local *local);
+
 /* MIB callbacks */
 void mac802154_dev_set_page_channel(struct net_device *dev, u8 page, u8 chan);
 

diff --git a/net/mac802154/util.c b/net/mac802154/util.c
index 0ed8b5bcbe8a77ca55e101f27595c8450dfba9a5..999534f644854b229ecd2ac2d5b8208c597239b2 100644 (file)
--- a/net/mac802154/util.c
+++ b/net/mac802154/util.c
@@ -83,6 +83,20 @@ void ieee802154_release_queue(struct ieee802154_local *local)
        spin_unlock_irqrestore(&local->phy->queue_lock, flags);
 }
 
+void ieee802154_disable_queue(struct ieee802154_local *local)
+{
+       struct ieee802154_sub_if_data *sdata;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+               if (!sdata->dev)
+                       continue;
+
+               netif_tx_disable(sdata->dev);
+       }
+       rcu_read_unlock();
+}
+
 enum hrtimer_restart ieee802154_xmit_ifs_timer(struct hrtimer *timer)
 {
        struct ieee802154_local *local =