From: Erez Shitrit <erezsh@xxxxxxxxxxxx>
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 <erezsh@xxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx5/core/dev.c | 73 ++++++++++++++++++++++++++
drivers/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 a62f4b6a21a5..ff60cf7342ca 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 124c7c3c3a00..6dbd637b4e66 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 88d6eb5b3a76..d26f18b39c4a 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;
--
2.13.0
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
