From 53ed30800d3fd36e1e9f7ba8014b150632f714b1 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 14 Jan 2025 19:53:17 -0800 Subject: [PATCH] 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: Joe Damato Reviewed-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250115035319.559603-10-kuba@kernel.org Signed-off-by: Jakub Kicinski --- include/linux/netdevice.h | 10 +++++++++- net/core/dev.c | 2 +- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 20e773bbd1819..a47ff20365f92 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 34db90f345d54..b6722ed9767a9 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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);