net: bcmgenet: hide status block before TX timestamping

stable inclusion
from stable-v5.10.114
commit e974c730f0afd3a5834aa7e42c9d1af9c28e5262
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5IY1V

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e974c730f0afd3a5834aa7e42c9d1af9c28e5262



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[ Upstream commit acac0541 ]

The hardware checksum offloading requires use of a transmit
status block inserted before the outgoing frame data, this was
updated in '9a9ba2a4 ("net: bcmgenet: always enable status blocks")'

However, skb_tx_timestamp() assumes that it is passed a raw frame
and PTP parsing chokes on this status block.

Fix this by calling __skb_pull(), which hides the TSB before calling
skb_tx_timestamp(), so an outgoing PTP packet is parsed correctly.

As the data in the skb has already been set up for DMA, and the
dma_unmap_* calls use a separately stored address, there is no
no effective change in the data transmission.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220424165307.591145-1-jonathan.lemon@gmail.com


Fixes: d03825fb ("net: bcmgenet: add skb_tx_timestamp call")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>