Subject: [PATCH net-next 5/7] eth: niu: fix calling napi_enable() in atomic context

From: Jakub Kicinski <[email-masked]>
Date: Tue, 21 Jan 2025 14:15:17 -0800

napi_enable() may sleep now, take netdev_lock() before np->lock.

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/sun/niu.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index d7459866d24c..72177fea1cfb 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -6086,7 +6086,7 @@ static void niu_enable_napi(struct niu *np)
 	int i;
 
 	for (i = 0; i < np->num_ldg; i++)
-		napi_enable(&np->ldg[i].napi);
+		napi_enable_locked(&np->ldg[i].napi);
 }
 
 static void niu_disable_napi(struct niu *np)
@@ -6116,7 +6116,9 @@ static int niu_open(struct net_device *dev)
 	if (err)
 		goto out_free_channels;
 
+	netdev_lock(dev);
 	niu_enable_napi(np);
+	netdev_unlock(dev);
 
 	spin_lock_irq(&np->lock);
 
@@ -6521,6 +6523,7 @@ static void niu_reset_task(struct work_struct *work)
 
 	niu_reset_buffers(np);
 
+	netdev_lock(np->dev);
 	spin_lock_irqsave(&np->lock, flags);
 
 	err = niu_init_hw(np);
@@ -6531,6 +6534,7 @@ static void niu_reset_task(struct work_struct *work)
 	}
 
 	spin_unlock_irqrestore(&np->lock, flags);
+	netdev_unlock(np->dev);
 }
 
 static void niu_tx_timeout(struct net_device *dev, unsigned int txqueue)
@@ -6761,7 +6765,9 @@ static int niu_change_mtu(struct net_device *dev, int new_mtu)
 
 	niu_free_channels(np);
 
+	netdev_lock(dev);
 	niu_enable_napi(np);
+	netdev_unlock(dev);
 
 	err = niu_alloc_channels(np);
 	if (err)
@@ -9937,6 +9943,7 @@ static int __maybe_unused niu_resume(struct device *dev_d)
 
 	spin_lock_irqsave(&np->lock, flags);
 
+	netdev_lock(dev);
 	err = niu_init_hw(np);
 	if (!err) {
 		np->timer.expires = jiffies + HZ;
@@ -9945,6 +9952,7 @@ static int __maybe_unused niu_resume(struct device *dev_d)
 	}
 
 	spin_unlock_irqrestore(&np->lock, flags);
+	netdev_unlock(dev);
 
 	return err;
 }
-- 
2.48.1