Commit 53ed3080 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

net: protect napi->irq with netdev_lock() 



Take netdev_lock() in netif_napi_set_irq(). All NAPI "control fields"
are now protected by that lock (most of the other ones are set during
napi add/del). The napi_hash_node is fully protected by the hash
spin lock, but close enough for the kdoc...

Reviewed-by: default avatarJoe Damato <jdamato@fastly.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250115035319.559603-10-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1bb86cf8

include/linux/netdevice.h

+9 −1
Original line number Diff line number Diff line
@@ -388,6 +388,7 @@ struct napi_struct { 
	unsigned long		gro_flush_timeout;

	unsigned long		irq_suspend_timeout;

	u32			defer_hard_irqs;

	/* all fields past this point are write-protected by netdev_lock */

	/* control-path-only fields follow */

	struct list_head	dev_list;

	struct hlist_node	napi_hash_node;
@@ -2706,11 +2707,18 @@ static inline void netdev_assert_locked_or_invisible(struct net_device *dev) 
		netdev_assert_locked(dev);

}



static inline void netif_napi_set_irq(struct napi_struct *napi, int irq)

static inline void netif_napi_set_irq_locked(struct napi_struct *napi, int irq)

{

	napi->irq = irq;

}



static inline void netif_napi_set_irq(struct napi_struct *napi, int irq)

{

	netdev_lock(napi->dev);

	netif_napi_set_irq_locked(napi, irq);

	netdev_unlock(napi->dev);

}



/* Default NAPI poll() weight

 * Device drivers are strongly advised to not use bigger value

 */

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -6957,7 +6957,7 @@ void netif_napi_add_weight_locked(struct net_device *dev, 
	 */

	if (dev->threaded && napi_kthread_create(napi))

		dev->threaded = false;

	netif_napi_set_irq(napi, -1);

	netif_napi_set_irq_locked(napi, -1);

}

EXPORT_SYMBOL(netif_napi_add_weight_locked);