net: enetc: preserve TX ring priority across reconfiguration
In the blamed commit, a rudimentary reallocation procedure for RX buffer descriptors was implemented, for the situation when their format changes between normal (no PTP) and extended (PTP). enetc_hwtstamp_set() calls enetc_close() and enetc_open() in a sequence, and this sequence loses information which was previously configured in the TX BDR Mode Register, specifically via the enetc_set_bdr_prio() call. The TX ring priority is configured by tc-mqprio and tc-taprio, and affects important things for TSN such as the TX time of packets. The issue manifests itself most visibly by the fact that isochron --txtime reports premature packet transmissions when PTP is first enabled on an enetc interface. Save the TX ring priority in a new field in struct enetc_bdr (occupies a 2 byte hole on arm64) in order to make this survive a ring reconfiguration. Fixes: 434cebab ("enetc: Add dynamic allocation of extended Rx BD rings") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com> Link: https://lore.kernel.org/r/20221122130936.1704151-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>
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