From 97834eba7c194659a72c5bb0f8c19c7055bb69ea Mon Sep 17 00:00:00 2001 From: Erez Shitrit Date: Wed, 7 Jun 2017 12:14:24 +0300 Subject: [PATCH] net/mlx5: Delay events till ib registration ends When mlx5_ib registers itself to mlx5_core as an interface, it will call mlx5_add_device which will call mlx5_ib interface add callback, in case the latter successfully returns, only then mlx5_core will add it to the interface list and async events will be forwarded to mlx5_ib. Between mlx5_ib interface add callback and mlx5_core adding the mlx5_ib interface to its devices list, arriving mlx5_core events can be missed by the new mlx5_ib registering interface. In other words: thread 1: mlx5_ib: mlx5_register_interface(dev) thread 1: mlx5_core: mlx5_add_device(dev) thread 1: mlx5_core: ctx = dev->add => (mlx5_ib)->mlx5_ib_add thread 2: mlx5_core_event: **new event arrives, forward to dev_list thread 1: mlx5_core: add_ctx_to_dev_list(ctx) /* previous event was missed by the new interface.*/ It is ok to miss events before dev->add (mlx5_ib)->mlx5_ib_add_device but not after. We fix this race by accumulating the events that come between the ib_register_device (inside mlx5_add_device->(dev->add)) till the adding to the list completes and fire them to the new registering interface after that. Fixes: f1ee87fe55c8 ("net/mlx5: Organize device list API in one place") Signed-off-by: Erez Shitrit Signed-off-by: Saeed Mahameed --- drivers/net/ethernet/mellanox/mlx5/core/dev.c | 73 +++++++++++++++++++ .../net/ethernet/mellanox/mlx5/core/main.c | 3 + include/linux/mlx5/driver.h | 3 + 3 files changed, 79 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/dev.c b/drivers/net/ethernet/mellanox/mlx5/core/dev.c index a62f4b6a21a50f..ff60cf7342ca5a 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/dev.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/dev.c @@ -45,11 +45,70 @@ struct mlx5_device_context { unsigned long state; }; +struct mlx5_delayed_event { + struct list_head list; + struct mlx5_core_dev *dev; + enum mlx5_dev_event event; + unsigned long param; +}; + enum { MLX5_INTERFACE_ADDED, MLX5_INTERFACE_ATTACHED, }; +static void add_delayed_event(struct mlx5_priv *priv, + struct mlx5_core_dev *dev, + enum mlx5_dev_event event, + unsigned long param) +{ + struct mlx5_delayed_event *delayed_event; + + delayed_event = kzalloc(sizeof(*delayed_event), GFP_ATOMIC); + if (!delayed_event) { + mlx5_core_err(dev, "event %d is missed\n", event); + return; + } + + mlx5_core_dbg(dev, "Accumulating event %d\n", event); + delayed_event->dev = dev; + delayed_event->event = event; + delayed_event->param = param; + list_add_tail(&delayed_event->list, &priv->waiting_events_list); +} + +static void fire_delayed_event_locked(struct mlx5_device_context *dev_ctx, + struct mlx5_core_dev *dev, + struct mlx5_priv *priv) +{ + struct mlx5_delayed_event *de; + struct mlx5_delayed_event *n; + + /* stop delaying events */ + priv->is_accum_events = false; + + /* fire all accumulated events before new event comes */ + list_for_each_entry_safe(de, n, &priv->waiting_events_list, list) { + dev_ctx->intf->event(dev, dev_ctx->context, de->event, de->param); + list_del(&de->list); + kfree(de); + } +} + +static void cleanup_delayed_evets(struct mlx5_priv *priv) +{ + struct mlx5_delayed_event *de; + struct mlx5_delayed_event *n; + + spin_lock_irq(&priv->ctx_lock); + priv->is_accum_events = false; + list_for_each_entry_safe(de, n, &priv->waiting_events_list, list) { + list_del(&de->list); + kfree(de); + } + spin_unlock_irq(&priv->ctx_lock); +} + void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv) { struct mlx5_device_context *dev_ctx; @@ -63,6 +122,12 @@ void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv) return; dev_ctx->intf = intf; + /* accumulating events that can come after mlx5_ib calls to + * ib_register_device, till adding that interface to the events list. + */ + + priv->is_accum_events = true; + dev_ctx->context = intf->add(dev); set_bit(MLX5_INTERFACE_ADDED, &dev_ctx->state); if (intf->attach) @@ -71,6 +136,9 @@ void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv) if (dev_ctx->context) { spin_lock_irq(&priv->ctx_lock); list_add_tail(&dev_ctx->list, &priv->ctx_list); + + fire_delayed_event_locked(dev_ctx, dev, priv); + #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING if (dev_ctx->intf->pfault) { if (priv->pfault) { @@ -84,6 +152,8 @@ void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv) spin_unlock_irq(&priv->ctx_lock); } else { kfree(dev_ctx); + /* delete all accumulated events */ + cleanup_delayed_evets(priv); } } @@ -341,6 +411,9 @@ void mlx5_core_event(struct mlx5_core_dev *dev, enum mlx5_dev_event event, spin_lock_irqsave(&priv->ctx_lock, flags); + if (priv->is_accum_events) + add_delayed_event(priv, dev, event, param); + list_for_each_entry(dev_ctx, &priv->ctx_list, list) if (dev_ctx->intf->event) dev_ctx->intf->event(dev, dev_ctx->context, event, param); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c index 124c7c3c3a0002..6dbd637b4e665f 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c @@ -1343,6 +1343,9 @@ static int init_one(struct pci_dev *pdev, mutex_init(&dev->pci_status_mutex); mutex_init(&dev->intf_state_mutex); + INIT_LIST_HEAD(&priv->waiting_events_list); + priv->is_accum_events = false; + #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING err = init_srcu_struct(&priv->pfault_srcu); if (err) { diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index 88d6eb5b3a7613..d26f18b39c4ad1 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -647,6 +647,9 @@ struct mlx5_priv { struct list_head ctx_list; spinlock_t ctx_lock; + struct list_head waiting_events_list; + bool is_accum_events; + struct mlx5_flow_steering *steering; struct mlx5_mpfs *mpfs; struct mlx5_eswitch *eswitch;