[PATCH wpan-next 09/20] net: mac802154: Introduce a global device lock
From: Miquel Raynal <miquel.raynal@bootlin.com>
Date: 2022-07-01 14:36:20
Subsystem:
ieee 802.15.4 subsystem, networking [general], the rest · Maintainers:
Alexander Aring, Stefan Schmidt, Miquel Raynal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The purpose of this device lock is to prevent the removal of the device while an asynchronous MLME operation happens. The RTNL works well for that but in a later series having the RTNL taken here will be problematic and will cause lockdep to warn us about a circular dependency. We don't really need the RTNL here, just a serialization over this operation. Replace the RTNL calls with this new lock. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> --- net/mac802154/ieee802154_i.h | 2 ++ net/mac802154/iface.c | 4 ++++ net/mac802154/main.c | 1 + net/mac802154/tx.c | 12 ++++++------ 4 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index 010365a6364e..b8775bcc9003 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h@@ -29,7 +29,9 @@ struct ieee802154_local { /* ieee802154 phy */ struct wpan_phy *phy; + /* Open/close counter and lock */ int open_count; + struct mutex device_lock; /* As in mac80211 slaves list is modified: * 1) under the RTNL
diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
index 7ac0c5685d3f..7715e17d9ba1 100644
--- a/net/mac802154/iface.c
+++ b/net/mac802154/iface.c@@ -315,11 +315,15 @@ static int mac802154_slave_close(struct net_device *dev) ASSERT_RTNL(); + mutex_lock(&local->device_lock); + netif_stop_queue(dev); local->open_count--; clear_bit(SDATA_STATE_RUNNING, &sdata->state); + mutex_unlock(&local->device_lock); + if (!local->open_count) ieee802154_stop_device(local);
diff --git a/net/mac802154/main.c b/net/mac802154/main.c
index a2da9d4c5273..e5fb7ed73663 100644
--- a/net/mac802154/main.c
+++ b/net/mac802154/main.c@@ -90,6 +90,7 @@ ieee802154_alloc_hw(size_t priv_data_len, const struct ieee802154_ops *ops) INIT_LIST_HEAD(&local->interfaces); mutex_init(&local->iflist_mtx); + mutex_init(&local->device_lock); tasklet_setup(&local->tasklet, ieee802154_tasklet_handler);
diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 9d8d43cf1e64..fb555797f326 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c@@ -143,14 +143,14 @@ int ieee802154_mlme_tx(struct ieee802154_local *local, { int ret; - /* Avoid possible calls to ->ndo_stop() when we asynchronously perform - * MLME transmissions. + /* Serialize possible calls to ->ndo_stop() when we asynchronously + * perform MLME transmissions. */ - rtnl_lock(); + mutex_lock(&local->device_lock); /* Ensure the device was not stopped, otherwise error out */ if (!local->open_count) { - rtnl_unlock(); + mutex_unlock(&local->device_lock); return -ENETDOWN; }
@@ -158,14 +158,14 @@ int ieee802154_mlme_tx(struct ieee802154_local *local, * net interface expects this cannot happen. */ if (WARN_ON_ONCE(!netif_running(sdata->dev))) { - rtnl_unlock(); + mutex_unlock(&local->device_lock); return -ENETDOWN; } ieee802154_tx(local, skb); ret = ieee802154_sync_queue(local); - rtnl_unlock(); + mutex_unlock(&local->device_lock); return ret; }
--
2.34.1