diff mbox series

[net-next,v2,09/11] net: protect napi->irq with netdev_lock()

Message ID 20250115035319.559603-10-kuba@kernel.org (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series net: use netdev->lock to protect NAPI | expand

Commit Message

Jakub Kicinski Jan. 15, 2025, 3:53 a.m. UTC 
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: Joe Damato <jdamato@fastly.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/linux/netdevice.h | 10 +++++++++-
 net/core/dev.c            |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

Comments

Kuniyuki Iwashima Jan. 15, 2025, 9:12 a.m. UTC | #1 
From: Jakub Kicinski <kuba@kernel.org>
Date: Tue, 14 Jan 2025 19:53:17 -0800
> 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: Joe Damato <jdamato@fastly.com>
> Reviewed-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
diff mbox series

Patch

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index bf3da95c9350..390fb70667bf 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -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
  */
diff --git a/net/core/dev.c b/net/core/dev.c
index d90bb100285d..495ceefcdc34 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6956,7 +6956,7 @@  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);