[PATCH net] net: lan966x: do not warn on MAC entries that are not port destined

[PATCH net] net: lan966x: do not warn on MAC entries that are not port destined

[Daniel Machon]

lan966x_mac_irq_handler() scans the rows of the MAC table that the
analyzer reports as changed, reads back all four columns of each row and
treats ANA_MACACCESS.DEST_IDX as a port number.

Before this patch, a destination index above num_phys_ports hits a
WARN_ON(). The driver installs such entries itself:
lan966x_mac_cpu_learn() uses PGID_CPU, and L2 multicast entries use a
general-purpose PGID. A row holding one of them is read back whenever
another entry in the same row is learned or aged out, so the scan warns
in normal operation, repeatedly once the MAC table is busy.

Skipping such a column is already the right behaviour. Drop the
WARN_ON() and keep the bounds check as a plain filter.

Found by an AI code review agent. Reproduced on a lan9668 board by
bridging two ports with a 10 s ageing time and sending three rounds of
2048 new source MACs: the base kernel warned 42 times from
lan966x_mac_irq_process(), the fixed kernel did not warn.

Fixes: 5ccd66e01cbe ("net: lan966x: add support for interrupts from analyzer")
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
---
 drivers/net/ethernet/microchip/lan966x/lan966x_mac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 7a2294a0d099e..986c60ac23432 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
@@ -447,7 +447,7 @@ static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
 
 			lan966x_mac_process_raw_entry(&raw_entries[column],
 						      mac, &vid, &dest_idx);
-			if (WARN_ON(dest_idx >= lan966x->num_phys_ports))
+			if (dest_idx >= lan966x->num_phys_ports)
 				continue;
 
 			/* If the entry in SW is found, then there is nothing
@@ -501,7 +501,7 @@ static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
 
 		lan966x_mac_process_raw_entry(&raw_entries[column],
 					      mac, &vid, &dest_idx);
-		if (WARN_ON(dest_idx >= lan966x->num_phys_ports))
+		if (dest_idx >= lan966x->num_phys_ports)
 			continue;
 
 		spin_lock(&lan966x->mac_lock);

---
base-commit: 6430fb7f1cc4e329e386521b7b208df443de92f2
change-id: 20261023-lan966x-mac-warn-46547fea2e7e

Best regards,
-- 
Daniel Machon <daniel.machon@microchip.com>

Re: [PATCH net] net: lan966x: do not warn on MAC entries that are not port destined

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Mon, 26 Oct 2026 14:46:28 +0100 you wrote:
> lan966x_mac_irq_handler() scans the rows of the MAC table that the
> analyzer reports as changed, reads back all four columns of each row and
> treats ANA_MACACCESS.DEST_IDX as a port number.
> 
> Before this patch, a destination index above num_phys_ports hits a
> WARN_ON(). The driver installs such entries itself:
> lan966x_mac_cpu_learn() uses PGID_CPU, and L2 multicast entries use a
> general-purpose PGID. A row holding one of them is read back whenever
> another entry in the same row is learned or aged out, so the scan warns
> in normal operation, repeatedly once the MAC table is busy.
> 
> [...]

Here is the summary with links:
  - [net] net: lan966x: do not warn on MAC entries that are not port destined
    https://git.kernel.org/netdev/net/c/2cffcf1aeabb

You are awesome, thank you!
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