From d4c22ec680c8db832ffc0b964c6008e65436cba8 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 5 Mar 2025 08:37:19 -0800 Subject: [PATCH] net: hold netdev instance lock during ndo_open/ndo_stop For the drivers that use shaper API, switch to the mode where core stack holds the netdev lock. This affects two drivers: * iavf - already grabs netdev lock in ndo_open/ndo_stop, so mostly remove these * netdevsim - switch to _locked APIs to avoid deadlock iavf_close diff is a bit confusing, the existing call looks like this: iavf_close() { netdev_lock() .. netdev_unlock() wait_event_timeout(down_waitqueue) } I change it to the following: netdev_lock() iavf_close() { .. netdev_unlock() wait_event_timeout(down_waitqueue) netdev_lock() // reusing this lock call } netdev_unlock() Since I'm reusing existing netdev_lock call, so it looks like I only add netdev_unlock. Cc: Saeed Mahameed Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250305163732.2766420-2-sdf@fomichev.me Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/intel/iavf/iavf_main.c | 14 ++++++------- drivers/net/netdevsim/netdev.c | 14 ++++++++----- include/linux/netdevice.h | 23 +++++++++++++++++++++ net/core/dev.c | 12 +++++++++++ net/core/dev.h | 6 ++++-- 5 files changed, 54 insertions(+), 15 deletions(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c index 71f11f64b13d..9f4d223dffcf 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_main.c +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c @@ -4562,22 +4562,21 @@ static int iavf_open(struct net_device *netdev) struct iavf_adapter *adapter = netdev_priv(netdev); int err; + netdev_assert_locked(netdev); + if (adapter->flags & IAVF_FLAG_PF_COMMS_FAILED) { dev_err(&adapter->pdev->dev, "Unable to open device due to PF driver failure.\n"); return -EIO; } - netdev_lock(netdev); while (!mutex_trylock(&adapter->crit_lock)) { /* If we are in __IAVF_INIT_CONFIG_ADAPTER state the crit_lock * is already taken and iavf_open is called from an upper * device's notifier reacting on NETDEV_REGISTER event. * We have to leave here to avoid dead lock. */ - if (adapter->state == __IAVF_INIT_CONFIG_ADAPTER) { - netdev_unlock(netdev); + if (adapter->state == __IAVF_INIT_CONFIG_ADAPTER) return -EBUSY; - } usleep_range(500, 1000); } @@ -4626,7 +4625,6 @@ static int iavf_open(struct net_device *netdev) iavf_irq_enable(adapter, true); mutex_unlock(&adapter->crit_lock); - netdev_unlock(netdev); return 0; @@ -4639,7 +4637,6 @@ static int iavf_open(struct net_device *netdev) iavf_free_all_tx_resources(adapter); err_unlock: mutex_unlock(&adapter->crit_lock); - netdev_unlock(netdev); return err; } @@ -4661,12 +4658,12 @@ static int iavf_close(struct net_device *netdev) u64 aq_to_restore; int status; - netdev_lock(netdev); + netdev_assert_locked(netdev); + mutex_lock(&adapter->crit_lock); if (adapter->state <= __IAVF_DOWN_PENDING) { mutex_unlock(&adapter->crit_lock); - netdev_unlock(netdev); return 0; } @@ -4719,6 +4716,7 @@ static int iavf_close(struct net_device *netdev) if (!status) netdev_warn(netdev, "Device resources not yet released\n"); + netdev_lock(netdev); mutex_lock(&adapter->crit_lock); adapter->aq_required |= aq_to_restore; mutex_unlock(&adapter->crit_lock); diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index a41dc79e9c2e..aaa3b58e2e3e 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -402,7 +402,7 @@ static int nsim_init_napi(struct netdevsim *ns) for (i = 0; i < dev->num_rx_queues; i++) { rq = ns->rq[i]; - netif_napi_add_config(dev, &rq->napi, nsim_poll, i); + netif_napi_add_config_locked(dev, &rq->napi, nsim_poll, i); } for (i = 0; i < dev->num_rx_queues; i++) { @@ -422,7 +422,7 @@ static int nsim_init_napi(struct netdevsim *ns) } for (i = 0; i < dev->num_rx_queues; i++) - __netif_napi_del(&ns->rq[i]->napi); + __netif_napi_del_locked(&ns->rq[i]->napi); return err; } @@ -452,7 +452,7 @@ static void nsim_enable_napi(struct netdevsim *ns) struct nsim_rq *rq = ns->rq[i]; netif_queue_set_napi(dev, i, NETDEV_QUEUE_TYPE_RX, &rq->napi); - napi_enable(&rq->napi); + napi_enable_locked(&rq->napi); } } @@ -461,6 +461,8 @@ static int nsim_open(struct net_device *dev) struct netdevsim *ns = netdev_priv(dev); int err; + netdev_assert_locked(dev); + err = nsim_init_napi(ns); if (err) return err; @@ -478,8 +480,8 @@ static void nsim_del_napi(struct netdevsim *ns) for (i = 0; i < dev->num_rx_queues; i++) { struct nsim_rq *rq = ns->rq[i]; - napi_disable(&rq->napi); - __netif_napi_del(&rq->napi); + napi_disable_locked(&rq->napi); + __netif_napi_del_locked(&rq->napi); } synchronize_net(); @@ -494,6 +496,8 @@ static int nsim_stop(struct net_device *dev) struct netdevsim *ns = netdev_priv(dev); struct netdevsim *peer; + netdev_assert_locked(dev); + netif_carrier_off(dev); peer = rtnl_dereference(ns->peer); if (peer) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 7ab86ec228b7..33066b155c84 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2753,6 +2753,29 @@ static inline void netdev_assert_locked_or_invisible(struct net_device *dev) netdev_assert_locked(dev); } +static inline bool netdev_need_ops_lock(struct net_device *dev) +{ + bool ret = false; + +#if IS_ENABLED(CONFIG_NET_SHAPER) + ret |= !!dev->netdev_ops->net_shaper_ops; +#endif + + return ret; +} + +static inline void netdev_lock_ops(struct net_device *dev) +{ + if (netdev_need_ops_lock(dev)) + netdev_lock(dev); +} + +static inline void netdev_unlock_ops(struct net_device *dev) +{ + if (netdev_need_ops_lock(dev)) + netdev_unlock(dev); +} + void netif_napi_set_irq_locked(struct napi_struct *napi, int irq); static inline void netif_napi_set_irq(struct napi_struct *napi, int irq) diff --git a/net/core/dev.c b/net/core/dev.c index 2dc705604509..7a327c782ea4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1627,6 +1627,8 @@ static int __dev_open(struct net_device *dev, struct netlink_ext_ack *extack) if (ret) return ret; + netdev_lock_ops(dev); + set_bit(__LINK_STATE_START, &dev->state); if (ops->ndo_validate_addr) @@ -1646,6 +1648,8 @@ static int __dev_open(struct net_device *dev, struct netlink_ext_ack *extack) add_device_randomness(dev->dev_addr, dev->addr_len); } + netdev_unlock_ops(dev); + return ret; } @@ -1716,11 +1720,19 @@ static void __dev_close_many(struct list_head *head) * We allow it to be called even after a DETACH hot-plug * event. */ + + /* TODO: move the lock up before clearing __LINK_STATE_START. + * Generates spurious lockdep warning. + */ + netdev_lock_ops(dev); + if (ops->ndo_stop) ops->ndo_stop(dev); netif_set_up(dev, false); netpoll_poll_enable(dev); + + netdev_unlock_ops(dev); } } diff --git a/net/core/dev.h b/net/core/dev.h index caa13e431a6b..25bb9d6afbce 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -134,9 +134,11 @@ static inline void netif_set_up(struct net_device *dev, bool value) else dev->flags &= ~IFF_UP; - netdev_lock(dev); + if (!netdev_need_ops_lock(dev)) + netdev_lock(dev); dev->up = value; - netdev_unlock(dev); + if (!netdev_need_ops_lock(dev)) + netdev_unlock(dev); } static inline void netif_set_gso_max_size(struct net_device *dev,