net: dsa: mv88e6xxx: Fix PCS link check on CMODE read error

mv88e6352_pcs_link_check() ignores errors returned by
port_get_cmode(). If the port status register read fails,
mv88e6352_port_get_cmode() returns without setting cmode. The link check
then compares an uninitialized value and may incorrectly treat the PCS
as active.

Save the return value and fail the link check after releasing the
register lock. marvell_c22_pcs_get_state() initializes the reported link
state to down before calling the check, so a read failure is handled
safely until a later poll succeeds.

This issue was found by a static analysis checker and confirmed by manual
source review.

Fixes: 85764555442f ("net: dsa: mv88e6xxx: convert 88e6352 to phylink_pcs")
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/20260813153131.3952970-1-ruoyuw560@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions