[PATCH 1/4] mac80211: fix 'reset' debugfs locking

[PATCH 1/4] mac80211: fix 'reset' debugfs locking

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

cfg80211 now calls suspend/resume with the wiphy lock
held, and while there's a problem with that needing
to be fixed, we should do the same in debugfs.

Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/debugfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 9245c0421bda..b5ff61b6448a 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -4,7 +4,7 @@
  *
  * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
- * Copyright (C) 2018 - 2019 Intel Corporation
+ * Copyright (C) 2018 - 2019, 2021 Intel Corporation
  */
 
 #include <linux/debugfs.h>
@@ -389,8 +389,10 @@ static ssize_t reset_write(struct file *file, const char __user *user_buf,
 	struct ieee80211_local *local = file->private_data;
 
 	rtnl_lock();
+	wiphy_lock(local->hw.wiphy);
 	__ieee80211_suspend(&local->hw, NULL);
 	__ieee80211_resume(&local->hw);
+	wiphy_unlock(local->hw.wiphy);
 	rtnl_unlock();
 
 	return count;
-- 
2.31.1

[PATCH 2/4] cfg80211: fix phy80211 symlink creation

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

When I moved around the code here, I neglected that we could still
call register_netdev() or similar without the wiphy mutex held,
which then calls cfg80211_register_wdev() - that's also done from
cfg80211_register_netdevice(), but the phy80211 symlink creation
was only there. Now, the symlink isn't needed for a *pure* wdev,
but a netdev not registered via cfg80211_register_wdev() should
still have the symlink, so move the creation to the right place.

Fixes: 2fe8ef106238 ("cfg80211: change netdev registration/unregistration semantics")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/wireless/core.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/net/wireless/core.c b/net/wireless/core.c
index 6fbf7537faf5..8d0883e81093 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -1340,6 +1340,11 @@ void cfg80211_register_wdev(struct cfg80211_registered_device *rdev,
 	rdev->devlist_generation++;
 	wdev->registered = true;
 
+	if (wdev->netdev &&
+	    sysfs_create_link(&wdev->netdev->dev.kobj, &rdev->wiphy.dev.kobj,
+			      "phy80211"))
+		pr_err("failed to add phy80211 symlink to netdev!\n");
+
 	nl80211_notify_iface(rdev, wdev, NL80211_CMD_NEW_INTERFACE);
 }
 
@@ -1365,14 +1370,6 @@ int cfg80211_register_netdevice(struct net_device *dev)
 	if (ret)
 		goto out;
 
-	if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
-			      "phy80211")) {
-		pr_err("failed to add phy80211 symlink to netdev!\n");
-		unregister_netdevice(dev);
-		ret = -EINVAL;
-		goto out;
-	}
-
 	cfg80211_register_wdev(rdev, wdev);
 	ret = 0;
 out:
-- 
2.31.1

[PATCH 3/4] cfg80211: shut down interfaces on failed resume

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

If resume fails, we should shut down all interfaces as the
hardware is probably dead. This was/is already done now in
mac80211, but we need to change that due to locking issues,
so move it here and do it without the wiphy lock held.

Fixes: 2fe8ef106238 ("cfg80211: change netdev registration/unregistration semantics")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/wireless/sysfs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/wireless/sysfs.c b/net/wireless/sysfs.c
index 9b959e3b09c6..0c3f05c9be27 100644
--- a/net/wireless/sysfs.c
+++ b/net/wireless/sysfs.c
@@ -133,6 +133,10 @@ static int wiphy_resume(struct device *dev)
 	if (rdev->wiphy.registered && rdev->ops->resume)
 		ret = rdev_resume(rdev);
 	wiphy_unlock(&rdev->wiphy);
+
+	if (ret)
+		cfg80211_shutdown_all_interfaces(&rdev->wiphy);
+
 	rtnl_unlock();
 
 	return ret;
-- 
2.31.1

[PATCH 4/4] mac80211: move interface shutdown out of wiphy lock

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

When reconfiguration fails, we shut down everything, but we
cannot call cfg80211_shutdown_all_interfaces() with the wiphy
mutex held. Since cfg80211 now calls it on resume errors, we
only need to do likewise for where we call reconfig (whether
directly or indirectly), but not under the wiphy lock.

Fixes: 2fe8ef106238 ("cfg80211: change netdev registration/unregistration semantics")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/debugfs.c | 7 ++++++-
 net/mac80211/main.c    | 7 ++++++-
 net/mac80211/util.c    | 2 --
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index b5ff61b6448a..fc34ae2b604c 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -387,12 +387,17 @@ static ssize_t reset_write(struct file *file, const char __user *user_buf,
 			   size_t count, loff_t *ppos)
 {
 	struct ieee80211_local *local = file->private_data;
+	int ret;
 
 	rtnl_lock();
 	wiphy_lock(local->hw.wiphy);
 	__ieee80211_suspend(&local->hw, NULL);
-	__ieee80211_resume(&local->hw);
+	ret = __ieee80211_resume(&local->hw);
 	wiphy_unlock(local->hw.wiphy);
+
+	if (ret)
+		cfg80211_shutdown_all_interfaces(local->hw.wiphy);
+
 	rtnl_unlock();
 
 	return count;
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 62145e5f9628..f33a3acd7f96 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -252,6 +252,7 @@ static void ieee80211_restart_work(struct work_struct *work)
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, restart_work);
 	struct ieee80211_sub_if_data *sdata;
+	int ret;
 
 	/* wait for scan work complete */
 	flush_workqueue(local->workqueue);
@@ -301,8 +302,12 @@ static void ieee80211_restart_work(struct work_struct *work)
 	/* wait for all packet processing to be done */
 	synchronize_net();
 
-	ieee80211_reconfig(local);
+	ret = ieee80211_reconfig(local);
 	wiphy_unlock(local->hw.wiphy);
+
+	if (ret)
+		cfg80211_shutdown_all_interfaces(local->hw.wiphy);
+
 	rtnl_unlock();
 }
 
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 0a0481f5af48..93d96a4f9c3e 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2178,8 +2178,6 @@ static void ieee80211_handle_reconfig_failure(struct ieee80211_local *local)
 	list_for_each_entry(ctx, &local->chanctx_list, list)
 		ctx->driver_present = false;
 	mutex_unlock(&local->chanctx_mtx);
-
-	cfg80211_shutdown_all_interfaces(local->hw.wiphy);
 }
 
 static void ieee80211_assign_chanctx(struct ieee80211_local *local,
-- 
2.31.1