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Commit 97834eba authored by Erez Shitrit's avatar Erez Shitrit Committed by Saeed Mahameed
Browse files

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: f1ee87fe ("net/mlx5: Organize device list API in one place")
Signed-off-by: default avatarErez Shitrit <erezsh@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
parent e80541ec

drivers/net/ethernet/mellanox/mlx5/core/dev.c

+73 −0
Original line number Original line Diff line number Diff line
@@ -45,11 +45,70 @@ struct mlx5_device_context { 
	unsigned long		state;

	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 {

enum {

	MLX5_INTERFACE_ADDED,

	MLX5_INTERFACE_ADDED,

	MLX5_INTERFACE_ATTACHED,

	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)

void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv)

{

{

	struct mlx5_device_context *dev_ctx;

	struct mlx5_device_context *dev_ctx;
@@ -63,6 +122,12 @@ void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv) 
		return;

		return;





	dev_ctx->intf = intf;

	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);

	dev_ctx->context = intf->add(dev);

	set_bit(MLX5_INTERFACE_ADDED, &dev_ctx->state);

	set_bit(MLX5_INTERFACE_ADDED, &dev_ctx->state);

	if (intf->attach)

	if (intf->attach)
@@ -71,6 +136,9 @@ void mlx5_add_device(struct mlx5_interface *intf, struct mlx5_priv *priv) 
	if (dev_ctx->context) {

	if (dev_ctx->context) {

		spin_lock_irq(&priv->ctx_lock);

		spin_lock_irq(&priv->ctx_lock);

		list_add_tail(&dev_ctx->list, &priv->ctx_list);

		list_add_tail(&dev_ctx->list, &priv->ctx_list);



		fire_delayed_event_locked(dev_ctx, dev, priv);



#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING

#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING

		if (dev_ctx->intf->pfault) {

		if (dev_ctx->intf->pfault) {

			if (priv->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);

		spin_unlock_irq(&priv->ctx_lock);

	} else {

	} else {

		kfree(dev_ctx);

		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);

	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)

	list_for_each_entry(dev_ctx, &priv->ctx_list, list)

		if (dev_ctx->intf->event)

		if (dev_ctx->intf->event)

			dev_ctx->intf->event(dev, dev_ctx->context, event, param);

			dev_ctx->intf->event(dev, dev_ctx->context, event, param);

drivers/net/ethernet/mellanox/mlx5/core/main.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -1343,6 +1343,9 @@ static int init_one(struct pci_dev *pdev, 
	mutex_init(&dev->pci_status_mutex);

	mutex_init(&dev->pci_status_mutex);

	mutex_init(&dev->intf_state_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

#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING

	err = init_srcu_struct(&priv->pfault_srcu);

	err = init_srcu_struct(&priv->pfault_srcu);

	if (err) {

	if (err) {

include/linux/mlx5/driver.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -647,6 +647,9 @@ struct mlx5_priv { 
	struct list_head        ctx_list;

	struct list_head        ctx_list;

	spinlock_t              ctx_lock;

	spinlock_t              ctx_lock;





	struct list_head	waiting_events_list;

	bool			is_accum_events;



	struct mlx5_flow_steering *steering;

	struct mlx5_flow_steering *steering;

	struct mlx5_mpfs        *mpfs;

	struct mlx5_mpfs        *mpfs;

	struct mlx5_eswitch     *eswitch;

	struct mlx5_eswitch     *eswitch;