net: usb: lan78xx: fix TX byte statistics for small packets

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commit 50988747c3 upstream.

Account for hardware auto-padding in TX byte counters to reflect actual
wire traffic.

The LAN7850 hardware automatically pads undersized frames to the minimum
Ethernet frame length (ETH_ZLEN, 60 bytes). However, the driver tracks
the network statistics based on the unpadded socket buffer length. This
results in the tx_bytes counter under-reporting the actual physical
bytes placed on the Ethernet wire for small packets (like short ARP or
ICMP requests).

Use max_t() to ensure the transmission statistics accurately account for
the hardware-generated padding.

Fixes: d383216a7e ("lan78xx: Introduce Tx URB processing improvements")
Cc: stable@vger.kernel.org
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20260305143429.530909-3-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Oleksij Rempel 2026-03-05 15:34:27 +01:00 • committed by Greg Kroah-Hartman

parent fa41007be6

commit f62ec1babb

1 changed files with 1 additions and 1 deletions

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drivers/net/usb/lan78xx.c

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