Subject: [PATCH net-next 6/7] eth: via-rhine: fix calling napi_enable() in atomic context

From: Jakub Kicinski <[email-masked]>
Date: Tue, 21 Jan 2025 14:15:18 -0800

napi_enable() may sleep now, take netdev_lock() before rp->lock.
napi_enable() is hidden inside init_registers().

Note that this patch orders netdev_lock after rp->task_lock,
to avoid having to take the netdev_lock() around disable path.

Fixes: 413f0271f396 ("net: protect NAPI enablement with netdev_lock()")
Reported-by: Dan Carpenter <[email-masked]>
Link: https://lore.kernel.org/[email-masked]
Signed-off-by: Jakub Kicinski <[email-masked]>
---
CC: [email-masked]
CC: [email-masked]
CC: [email-masked]
---
 drivers/net/ethernet/via/via-rhine.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/ethernet/via/via-rhine.c b/drivers/net/ethernet/via/via-rhine.c
index 894911f3d560..f27157561082 100644
--- a/drivers/net/ethernet/via/via-rhine.c
+++ b/drivers/net/ethernet/via/via-rhine.c
@@ -1696,7 +1696,10 @@ static int rhine_open(struct net_device *dev)
 	rhine_power_init(dev);
 	rhine_chip_reset(dev);
 	rhine_task_enable(rp);
+
+	netdev_lock(dev);
 	init_registers(dev);
+	netdev_unlock(dev);
 
 	netif_dbg(rp, ifup, dev, "%s() Done - status %04x MII status: %04x\n",
 		  __func__, ioread16(ioaddr + ChipCmd),
@@ -1727,6 +1730,8 @@ static void rhine_reset_task(struct work_struct *work)
 
 	napi_disable(&rp->napi);
 	netif_tx_disable(dev);
+
+	netdev_lock(dev);
 	spin_lock_bh(&rp->lock);
 
 	/* clear all descriptors */
@@ -1740,6 +1745,7 @@ static void rhine_reset_task(struct work_struct *work)
 	init_registers(dev);
 
 	spin_unlock_bh(&rp->lock);
+	netdev_unlock(dev);
 
 	netif_trans_update(dev); /* prevent tx timeout */
 	dev->stats.tx_errors++;
@@ -2541,9 +2547,12 @@ static int rhine_resume(struct device *device)
 	alloc_tbufs(dev);
 	rhine_reset_rbufs(rp);
 	rhine_task_enable(rp);
+
+	netdev_lock(dev);
 	spin_lock_bh(&rp->lock);
 	init_registers(dev);
 	spin_unlock_bh(&rp->lock);
+	netdev_unlock(dev);
 
 	netif_device_attach(dev);
 
-- 
2.48.1