linux-kernel - [PATCH 3/5] wilc: wifi: do not realloc workqueue everytime an interface is added

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Message-Id: <20240115-wilc_1000_fixes-v1-3-54d29463a738@bootlin.com>
Date: Mon, 15 Jan 2024 15:56:32 +0100
From: Alexis Lothoré <alexis.lothore@...tlin.com>
To: linux-wireless@...r.kernel.org
Cc: Ajay Singh <ajay.kathat@...rochip.com>, 
 Claudiu Beznea <claudiu.beznea@...on.dev>, Kalle Valo <kvalo@...nel.org>, 
 David Mosberger-Tang <davidm@...uge.net>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 linux-kernel@...r.kernel.org, 
 Alexis Lothoré <alexis.lothore@...tlin.com>
Subject: [PATCH 3/5] wilc: wifi: do not realloc workqueue everytime an
 interface is added

From: Ajay Singh <ajay.kathat@...rochip.com>

Commit 09ed8bfc5215 ("wilc1000: Rename workqueue from "WILC_wq" to
"NETDEV-wq"") moved workqueue creation in wilc_netdev_ifc_init in order to
set the interface name in the workqueue name. However, while the driver
needs only one workqueue, the wilc_netdev_ifc_init is called each time we
add an interface over a phy, which in turns overwrite the workqueue with a
new one. This can be observed with the following commands:

for i in $(seq 0 10)
do
  iw phy phy0 interface add wlan1 type managed
  iw dev wlan1 del
done
ps -eo pid,comm|grep wlan

 39 kworker/R-wlan0
 98 kworker/R-wlan1
102 kworker/R-wlan1
105 kworker/R-wlan1
108 kworker/R-wlan1
111 kworker/R-wlan1
114 kworker/R-wlan1
117 kworker/R-wlan1
120 kworker/R-wlan1
123 kworker/R-wlan1
126 kworker/R-wlan1
129 kworker/R-wlan1

Fix this leakage by putting back hif_workqueue allocation in
wilc_cfg80211_init. Regarding the workqueue name, it is indeed relevant to
set it lowercase, however it is not  attached to a specific netdev, so
enforcing netdev name in the name is not so relevant. Still, enrich the
name with the wiphy name to make it clear which phy is using the workqueue.

Fixes: 09ed8bfc5215 ("wilc1000: Rename workqueue from "WILC_wq" to "NETDEV-wq"")
Signed-off-by: Ajay Singh <ajay.kathat@...rochip.com>
Co-developed-by: Alexis Lothoré <alexis.lothore@...tlin.com>
Signed-off-by: Alexis Lothoré <alexis.lothore@...tlin.com>
---
This patch has initially been done by Ajay, and I slightly reworked it

09ed8bfc5215 ("wilc1000: Rename workqueue from "WILC_wq" to "NETDEV-wq"")
also mentions that this workqueue allocation move has also been done to
make wq alloc/dealloc symmetric: the revert set back the assymetry, and that
remains something to be fixed. Deallocation should likely be moved from
netdev.c to cfg80211, but that would be a dedicated rework topic
---
 drivers/net/wireless/microchip/wilc1000/cfg80211.c | 11 ++++++++++-
 drivers/net/wireless/microchip/wilc1000/netdev.c   | 10 +---------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/microchip/wilc1000/cfg80211.c b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
index ad2509d8c99a..2d0474e6404e 100644
--- a/drivers/net/wireless/microchip/wilc1000/cfg80211.c
+++ b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
@@ -1804,15 +1804,24 @@ int wilc_cfg80211_init(struct wilc **wilc, struct device *dev, int io_type,
 	INIT_LIST_HEAD(&wl->rxq_head.list);
 	INIT_LIST_HEAD(&wl->vif_list);
 
+	wl->hif_workqueue = alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM,
+						    wiphy_name(wl->wiphy));
+	if (!wl->hif_workqueue) {
+		ret = -ENOMEM;
+		goto free_cfg;
+	}
 	vif = wilc_netdev_ifc_init(wl, "wlan%d", WILC_STATION_MODE,
 				   NL80211_IFTYPE_STATION, false);
 	if (IS_ERR(vif)) {
 		ret = PTR_ERR(vif);
-		goto free_cfg;
+		goto free_hq;
 	}
 
 	return 0;
 
+free_hq:
+	destroy_workqueue(wl->hif_workqueue);
+
 free_cfg:
 	wilc_wlan_cfg_deinit(wl);
 
diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.c b/drivers/net/wireless/microchip/wilc1000/netdev.c
index f3b9709f8730..da52f4a9c1fe 100644
--- a/drivers/net/wireless/microchip/wilc1000/netdev.c
+++ b/drivers/net/wireless/microchip/wilc1000/netdev.c
@@ -989,13 +989,6 @@ struct wilc_vif *wilc_netdev_ifc_init(struct wilc *wl, const char *name,
 		goto error;
 	}
 
-	wl->hif_workqueue = alloc_ordered_workqueue("%s-wq", WQ_MEM_RECLAIM,
-						    ndev->name);
-	if (!wl->hif_workqueue) {
-		ret = -ENOMEM;
-		goto unregister_netdev;
-	}
-
 	ndev->needs_free_netdev = true;
 	vif->iftype = vif_type;
 	vif->idx = wilc_get_available_idx(wl);
@@ -1008,12 +1001,11 @@ struct wilc_vif *wilc_netdev_ifc_init(struct wilc *wl, const char *name,
 
 	return vif;
 
-unregister_netdev:
+error:
 	if (rtnl_locked)
 		cfg80211_unregister_netdevice(ndev);
 	else
 		unregister_netdev(ndev);
-  error:
 	free_netdev(ndev);
 	return ERR_PTR(ret);
 }

-- 
2.42.1