Re: [PATCH v2 10/15] net: rnpgbe: Add netdev irq in open

[Simon Horman <horms@kernel.org>]

On Mon, Jul 21, 2025 at 07:32:33PM +0800, Dong Yibo wrote:
> Initialize irq for tx/rx in open func.
> 
> Signed-off-by: Dong Yibo <dong100@mucse.com>

...

> diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c

...

> +/**
> + * rnpgbe_set_mac_hw_ops_n500 - Setup mac address to hw
> + * @hw: pointer to hw structure
> + * @mac: pointer to mac addr
> + *
> + * Setup a mac address to hw.
> + **/
> +static void rnpgbe_set_mac_hw_ops_n500(struct mucse_hw *hw, u8 *mac)
> +{
> +	struct mucse_eth_info *eth = &hw->eth;
> +	struct mucse_mac_info *mac_info = &hw->mac;

Reverse xmas tree here please.

> +
> +	/* use idx 0 */
> +	eth->ops.set_rar(eth, 0, mac);
> +	mac_info->ops.set_mac(mac_info, mac, 0);
> +}

...

> diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c

...

> +/**
> + * rnpgbe_msix_clean_rings - msix irq handler for ring irq
> + * @irq: irq num
> + * @data: private data
> + *
> + * rnpgbe_msix_clean_rings handle irq from ring, start napi

Please also document the return value of this function.
Likewise for rnpgbe_request_msix_irqs(), rnpgbe_intr() and
rnpgbe_request_irq().

> + **/
> +static irqreturn_t rnpgbe_msix_clean_rings(int irq, void *data)
> +{
> +	return IRQ_HANDLED;
> +}

...

> +/**
> + * rnpgbe_request_msix_irqs - Initialize MSI-X interrupts
> + * @mucse: pointer to private structure
> + *
> + * rnpgbe_request_msix_irqs allocates MSI-X vectors and requests
> + * interrupts from the kernel.
> + **/
> +static int rnpgbe_request_msix_irqs(struct mucse *mucse)
> +{
> +	struct net_device *netdev = mucse->netdev;
> +	int q_off = mucse->q_vector_off;
> +	struct msix_entry *entry;
> +	int i = 0;
> +	int err;
> +
> +	for (i = 0; i < mucse->num_q_vectors; i++) {
> +		struct mucse_q_vector *q_vector = mucse->q_vector[i];
> +
> +		entry = &mucse->msix_entries[i + q_off];
> +		if (q_vector->tx.ring && q_vector->rx.ring) {
> +			snprintf(q_vector->name, sizeof(q_vector->name) - 1,
> +				 "%s-%s-%d", netdev->name, "TxRx", i);

Probably the full range of i is not used, in particular I assume
it is never negative, and thus i and mucse->num_q_vectors
could be unsigned int rather than int.

But as it stands q_vector->name is once character too short to
fit the maximum possible string formatted by snprintf().

I was able to address the warning flagged by GCC 15.0.0 about this by
increasing the size of q_vector->name by one byte.

  .../rnpgbe_lib.c: In function 'rnpgbe_request_irq':
  .../rnpgbe_lib.c:1015:43: warning: 'snprintf' output may be truncated before the last format character [-Wformat-truncation=]
   1015 |                                  "%s-%s-%d", netdev->name, "TxRx", i);
        |                                           ^
  In function 'rnpgbe_request_msix_irqs',
      inlined from 'rnpgbe_request_irq' at drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c:1069:9:
  .../rnpgbe_lib.c:1014:25: note: 'snprintf' output between 8 and 33 bytes into a destination of size 32
   1014 |                         snprintf(q_vector->name, sizeof(q_vector->name) - 1,
        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1015 |                                  "%s-%s-%d", netdev->name, "TxRx", i);
        |                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


> +		} else {
> +			/* skip this unused q_vector */
> +			continue;
> +		}
> +		err = request_irq(entry->vector, &rnpgbe_msix_clean_rings, 0,
> +				  q_vector->name, q_vector);
> +		if (err)
> +			goto free_queue_irqs;
> +		/* register for affinity change notifications */
> +		q_vector->affinity_notify.notify = rnpgbe_irq_affinity_notify;
> +		q_vector->affinity_notify.release = rnpgbe_irq_affinity_release;
> +		irq_set_affinity_notifier(entry->vector,
> +					  &q_vector->affinity_notify);
> +		irq_set_affinity_hint(entry->vector, &q_vector->affinity_mask);
> +	}
> +
> +	return 0;
> +
> +free_queue_irqs:
> +	while (i) {
> +		i--;
> +		entry = &mucse->msix_entries[i + q_off];
> +		irq_set_affinity_hint(entry->vector, NULL);
> +		free_irq(entry->vector, mucse->q_vector[i]);
> +		irq_set_affinity_notifier(entry->vector, NULL);
> +		irq_set_affinity_hint(entry->vector, NULL);
> +	}
> +	return err;
> +}

...