net: lan966x: don't disable hardirqs in fdma tx clear path

lan966x_fdma_tx_clear_buf() runs from the NAPI poll and frees the
buffers of completed tx DCBs with napi_consume_skb(),
page_pool_recycle_direct() and xdp_return_frame_bulk(), under
lan966x->tx_lock.

Before this patch, the lock is taken with spin_lock_irqsave(), so the
buffers are freed with hardirqs disabled. RX skbs are marked for
page_pool recycling, so when such an skb is forwarded back out and its
tx completion frees it here, the free path reaches __page_pool_put_page(),
which warns via lockdep_assert_no_hardirq().

Take tx_lock with a plain spin_lock(), as the other tx_lock users,
lan966x_port_xmit() and lan966x_fdma_xmit_xdpf(), already do.
tx_clear_buf() runs from the NAPI poll, so disabling hardirqs there is
not needed.

Found with lockdep enabled (CONFIG_PROVE_LOCKING), which the assert
depends on. Reproduced on a lan9668 board by redirecting received frames
out of another port with tc mirred.

Fixes: 11871aba1974 ("net: lan96x: Use page_pool API")
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://patch.msgid.link/20261026-lan966x-fdma-tx-clear-hardirq-v1-1-5f70f026a2e4@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions