net: dsa: felix: fix race between reading PSFP stats and port stats

Both PSFP stats and the port stats read by ocelot_check_stats_work() are
indirectly read through the same mechanism - write to STAT_CFG:STAT_VIEW,
read from SYS:STAT:CNT[n].

It's just that for port stats, we write STAT_VIEW with the index of the
port, and for PSFP stats, we write STAT_VIEW with the filter index.

So if we allow them to run concurrently, ocelot_check_stats_work() may
change the view from vsc9959_psfp_counters_get(), and vice versa.

Fixes: 7d4b564d6a ("net: dsa: felix: support psfp filter on vsc9959")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220629183007.3808130-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean 2022-06-29 21:30:07 +03:00 committed by Jakub Kicinski
parent 839b92fede
commit 58bf4db695

View file

@ -1886,6 +1886,8 @@ static void vsc9959_psfp_sgi_table_del(struct ocelot *ocelot,
static void vsc9959_psfp_counters_get(struct ocelot *ocelot, u32 index,
struct felix_stream_filter_counters *counters)
{
mutex_lock(&ocelot->stats_lock);
ocelot_rmw(ocelot, SYS_STAT_CFG_STAT_VIEW(index),
SYS_STAT_CFG_STAT_VIEW_M,
SYS_STAT_CFG);
@ -1900,6 +1902,8 @@ static void vsc9959_psfp_counters_get(struct ocelot *ocelot, u32 index,
SYS_STAT_CFG_STAT_VIEW(index) |
SYS_STAT_CFG_STAT_CLEAR_SHOT(0x10),
SYS_STAT_CFG);
mutex_unlock(&ocelot->stats_lock);
}
static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,