net: dsa: felix: check the 32-bit PSFP stats against overflow
The Felix PSFP counters suffer from the same problem as the ocelot ndo_get_stats64 ones - they are 32-bit, so they can easily overflow and this can easily go undetected. Add a custom hook in ocelot_check_stats_work() through which driver specific actions can be taken, and update the stats for the existing PSFP filters from that hook. Previously, vsc9959_psfp_filter_add() and vsc9959_psfp_filter_del() were serialized with respect to each other via rtnl_lock(). However, with the new entry point into &psfp->sfi_list coming from the periodic worker, we now need an explicit mutex to serialize access to these lists. We used to keep a struct felix_stream_filter_counters on stack, through which vsc9959_psfp_stats_get() - a FLOW_CLS_STATS callback - would retrieve data from vsc9959_psfp_counters_get(). We need to become smarter about that in 3 ways: - we need to keep a persistent set of counters for each stream instead of keeping them on stack - we need to promote those counters from u32 to u64, and create a procedure that properly keeps 64-bit counters. Since we clear the hardware counters anyway, and we poll every 2 seconds, a simple increment of a u64 counter with a u32 value will perfectly do the job. - FLOW_CLS_STATS also expect incremental counters, so we also need to zeroize our u64 counters every time sch_flower calls us Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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