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can: rx-offload: can_rx_offload_threaded_irq_finish(): add new function to be called from threaded interrupt

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After reading all CAN frames from the controller in the IRQ handler
and storing them into a skb_queue, the driver calls napi_schedule().
In the napi poll function the skb from the skb_queue are then pushed
into the networking stack.

However if napi_schedule() is called from a threaded IRQ handler this
triggers the following error:

| NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!

To avoid this, create a new rx-offload
function (can_rx_offload_threaded_irq_finish()) with a call to
local_bh_disable()/local_bh_enable() around the napi_schedule() call.

Convert all drivers that call can_rx_offload_irq_finish() from
threaded IRQ context to can_rx_offload_threaded_irq_finish().

Link: https://lore.kernel.org/r/20210724204745.736053-4-mkl@pengutronix.de
Suggested-by: Daniel Glöckner <dg@emlix.com>
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Marc Kleine-Budde 2021-05-10 22:51:39 +02:00
parent 1e0d8e507e
commit 30bfec4fec
4 changed files with 27 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
drivers/net/can/dev/rx-offload.c
View file

@ -299,6 +299,29 @@ void can_rx_offload_irq_finish(struct can_rx_offload *offload)
}
EXPORT_SYMBOL_GPL(can_rx_offload_irq_finish);
void can_rx_offload_threaded_irq_finish(struct can_rx_offload *offload)
{
unsigned long flags;
int queue_len;
if (skb_queue_empty_lockless(&offload->skb_irq_queue))
return;
spin_lock_irqsave(&offload->skb_queue.lock, flags);
skb_queue_splice_tail_init(&offload->skb_irq_queue, &offload->skb_queue);
spin_unlock_irqrestore(&offload->skb_queue.lock, flags);
queue_len = skb_queue_len(&offload->skb_queue);
if (queue_len > offload->skb_queue_len_max / 8)
netdev_dbg(offload->dev, "%s: queue_len=%d\n",
__func__, queue_len);
local_bh_disable();
napi_schedule(&offload->napi);
local_bh_enable();
}
EXPORT_SYMBOL_GPL(can_rx_offload_threaded_irq_finish);
static int can_rx_offload_init_queue(struct net_device *dev,
struct can_rx_offload *offload,
unsigned int weight)

2
drivers/net/can/m_can/m_can.c
View file

@ -1059,7 +1059,7 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
}
if (cdev->is_peripheral)
can_rx_offload_irq_finish(&cdev->offload);
can_rx_offload_threaded_irq_finish(&cdev->offload);
return IRQ_HANDLED;
}

4
drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
View file

@ -2196,7 +2196,7 @@ static irqreturn_t mcp251xfd_irq(int irq, void *dev_id)
priv->regs_status.intf);
if (!(intf_pending)) {
can_rx_offload_irq_finish(&priv->offload);
can_rx_offload_threaded_irq_finish(&priv->offload);
return handled;
}
@ -2298,7 +2298,7 @@ static irqreturn_t mcp251xfd_irq(int irq, void *dev_id)
} while (1);
out_fail:
can_rx_offload_irq_finish(&priv->offload);
can_rx_offload_threaded_irq_finish(&priv->offload);
netdev_err(priv->ndev, "IRQ handler returned %d (intf=0x%08x).\n",
err, priv->regs_status.intf);

1
include/linux/can/rx-offload.h
View file

@ -50,6 +50,7 @@ unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
int can_rx_offload_queue_tail(struct can_rx_offload *offload,
struct sk_buff *skb);
void can_rx_offload_irq_finish(struct can_rx_offload *offload);
void can_rx_offload_threaded_irq_finish(struct can_rx_offload *offload);
void can_rx_offload_del(struct can_rx_offload *offload);
void can_rx_offload_enable(struct can_rx_offload *offload);