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>

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index 858ccf1..b815bc4 100644 (file)
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -2046,7 +2046,15 @@ struct felix_stream {
        u32 ssid;
 };
 
+struct felix_stream_filter_counters {
+       u64 match;
+       u64 not_pass_gate;
+       u64 not_pass_sdu;
+       u64 red;
+};
+
 struct felix_stream_filter {
+       struct felix_stream_filter_counters stats;
        struct list_head list;
        refcount_t refcount;
        u32 index;
@@ -2061,13 +2069,6 @@ struct felix_stream_filter {
        u32 maxsdu;
 };
 
-struct felix_stream_filter_counters {
-       u32 match;
-       u32 not_pass_gate;
-       u32 not_pass_sdu;
-       u32 red;
-};
-
 struct felix_stream_gate {
        u32 index;
        u8 enable;
@@ -2571,31 +2572,6 @@ 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->stat_view_lock);
-
-       ocelot_rmw(ocelot, SYS_STAT_CFG_STAT_VIEW(index),
-                  SYS_STAT_CFG_STAT_VIEW_M,
-                  SYS_STAT_CFG);
-
-       counters->match = ocelot_read(ocelot, SYS_COUNT_SF_MATCHING_FRAMES);
-       counters->not_pass_gate = ocelot_read(ocelot,
-                                             SYS_COUNT_SF_NOT_PASSING_FRAMES);
-       counters->not_pass_sdu = ocelot_read(ocelot,
-                                            SYS_COUNT_SF_NOT_PASSING_SDU);
-       counters->red = ocelot_read(ocelot, SYS_COUNT_SF_RED_FRAMES);
-
-       /* Clear the PSFP counter. */
-       ocelot_write(ocelot,
-                    SYS_STAT_CFG_STAT_VIEW(index) |
-                    SYS_STAT_CFG_STAT_CLEAR_SHOT(0x10),
-                    SYS_STAT_CFG);
-
-       mutex_unlock(&ocelot->stat_view_lock);
-}
-
 static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,
                                   struct flow_cls_offload *f)
 {
@@ -2620,6 +2596,8 @@ static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,
                return ret;
        }
 
+       mutex_lock(&psfp->lock);
+
        flow_action_for_each(i, a, &f->rule->action) {
                switch (a->id) {
                case FLOW_ACTION_GATE:
@@ -2661,6 +2639,7 @@ static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,
                        sfi.maxsdu = a->police.mtu;
                        break;
                default:
+                       mutex_unlock(&psfp->lock);
                        return -EOPNOTSUPP;
                }
        }
@@ -2730,6 +2709,8 @@ static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,
                goto err;
        }
 
+       mutex_unlock(&psfp->lock);
+
        return 0;
 
 err:
@@ -2739,6 +2720,8 @@ err:
        if (sfi.fm_valid)
                ocelot_vcap_policer_del(ocelot, sfi.fmid);
 
+       mutex_unlock(&psfp->lock);
+
        return ret;
 }
 
@@ -2746,18 +2729,22 @@ static int vsc9959_psfp_filter_del(struct ocelot *ocelot,
                                   struct flow_cls_offload *f)
 {
        struct felix_stream *stream, tmp, *stream_entry;
+       struct ocelot_psfp_list *psfp = &ocelot->psfp;
        static struct felix_stream_filter *sfi;
-       struct ocelot_psfp_list *psfp;
 
-       psfp = &ocelot->psfp;
+       mutex_lock(&psfp->lock);
 
        stream = vsc9959_stream_table_get(&psfp->stream_list, f->cookie);
-       if (!stream)
+       if (!stream) {
+               mutex_unlock(&psfp->lock);
                return -ENOMEM;
+       }
 
        sfi = vsc9959_psfp_sfi_table_get(&psfp->sfi_list, stream->sfid);
-       if (!sfi)
+       if (!sfi) {
+               mutex_unlock(&psfp->lock);
                return -ENOMEM;
+       }
 
        if (sfi->sg_valid)
                vsc9959_psfp_sgi_table_del(ocelot, sfi->sgid);
@@ -2783,27 +2770,83 @@ static int vsc9959_psfp_filter_del(struct ocelot *ocelot,
                                          stream_entry->ports);
        }
 
+       mutex_unlock(&psfp->lock);
+
        return 0;
 }
 
+static void vsc9959_update_sfid_stats(struct ocelot *ocelot,
+                                     struct felix_stream_filter *sfi)
+{
+       struct felix_stream_filter_counters *s = &sfi->stats;
+       u32 match, not_pass_gate, not_pass_sdu, red;
+       u32 sfid = sfi->index;
+
+       lockdep_assert_held(&ocelot->stat_view_lock);
+
+       ocelot_rmw(ocelot, SYS_STAT_CFG_STAT_VIEW(sfid),
+                  SYS_STAT_CFG_STAT_VIEW_M,
+                  SYS_STAT_CFG);
+
+       match = ocelot_read(ocelot, SYS_COUNT_SF_MATCHING_FRAMES);
+       not_pass_gate = ocelot_read(ocelot, SYS_COUNT_SF_NOT_PASSING_FRAMES);
+       not_pass_sdu = ocelot_read(ocelot, SYS_COUNT_SF_NOT_PASSING_SDU);
+       red = ocelot_read(ocelot, SYS_COUNT_SF_RED_FRAMES);
+
+       /* Clear the PSFP counter. */
+       ocelot_write(ocelot,
+                    SYS_STAT_CFG_STAT_VIEW(sfid) |
+                    SYS_STAT_CFG_STAT_CLEAR_SHOT(0x10),
+                    SYS_STAT_CFG);
+
+       s->match += match;
+       s->not_pass_gate += not_pass_gate;
+       s->not_pass_sdu += not_pass_sdu;
+       s->red += red;
+}
+
+/* Caller must hold &ocelot->stat_view_lock */
+static void vsc9959_update_stats(struct ocelot *ocelot)
+{
+       struct ocelot_psfp_list *psfp = &ocelot->psfp;
+       struct felix_stream_filter *sfi;
+
+       mutex_lock(&psfp->lock);
+
+       list_for_each_entry(sfi, &psfp->sfi_list, list)
+               vsc9959_update_sfid_stats(ocelot, sfi);
+
+       mutex_unlock(&psfp->lock);
+}
+
 static int vsc9959_psfp_stats_get(struct ocelot *ocelot,
                                  struct flow_cls_offload *f,
                                  struct flow_stats *stats)
 {
-       struct felix_stream_filter_counters counters;
-       struct ocelot_psfp_list *psfp;
+       struct ocelot_psfp_list *psfp = &ocelot->psfp;
+       struct felix_stream_filter_counters *s;
+       static struct felix_stream_filter *sfi;
        struct felix_stream *stream;
 
-       psfp = &ocelot->psfp;
        stream = vsc9959_stream_table_get(&psfp->stream_list, f->cookie);
        if (!stream)
                return -ENOMEM;
 
-       vsc9959_psfp_counters_get(ocelot, stream->sfid, &counters);
+       sfi = vsc9959_psfp_sfi_table_get(&psfp->sfi_list, stream->sfid);
+       if (!sfi)
+               return -EINVAL;
+
+       mutex_lock(&ocelot->stat_view_lock);
+
+       vsc9959_update_sfid_stats(ocelot, sfi);
+
+       s = &sfi->stats;
+       stats->pkts = s->match;
+       stats->drops = s->not_pass_gate + s->not_pass_sdu + s->red;
 
-       stats->pkts = counters.match;
-       stats->drops = counters.not_pass_gate + counters.not_pass_sdu +
-                      counters.red;
+       memset(s, 0, sizeof(*s));
+
+       mutex_unlock(&ocelot->stat_view_lock);
 
        return 0;
 }
@@ -2815,6 +2858,7 @@ static void vsc9959_psfp_init(struct ocelot *ocelot)
        INIT_LIST_HEAD(&psfp->stream_list);
        INIT_LIST_HEAD(&psfp->sfi_list);
        INIT_LIST_HEAD(&psfp->sgi_list);
+       mutex_init(&psfp->lock);
 }
 
 /* When using cut-through forwarding and the egress port runs at a higher data
@@ -2913,6 +2957,7 @@ static const struct ocelot_ops vsc9959_ops = {
        .psfp_stats_get         = vsc9959_psfp_stats_get,
        .cut_through_fwd        = vsc9959_cut_through_fwd,
        .tas_clock_adjust       = vsc9959_tas_clock_adjust,
+       .update_stats           = vsc9959_update_stats,
 };
 
 static const struct felix_info felix_info_vsc9959 = {

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index a677a18..8e06332 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1934,6 +1934,9 @@ static void ocelot_check_stats_work(struct work_struct *work)
                spin_unlock(&ocelot->stats_lock);
        }
 
+       if (!err && ocelot->ops->update_stats)
+               ocelot->ops->update_stats(ocelot);
+
        mutex_unlock(&ocelot->stat_view_lock);
 
        if (err)

diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index e85fb3b..bc6ca1b 100644 (file)
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -729,6 +729,7 @@ struct ocelot_ops {
                              struct flow_stats *stats);
        void (*cut_through_fwd)(struct ocelot *ocelot);
        void (*tas_clock_adjust)(struct ocelot *ocelot);
+       void (*update_stats)(struct ocelot *ocelot);
 };
 
 struct ocelot_vcap_policer {
@@ -766,6 +767,8 @@ struct ocelot_psfp_list {
        struct list_head stream_list;
        struct list_head sfi_list;
        struct list_head sgi_list;
+       /* Serialize access to the lists */
+       struct mutex lock;
 };
 
 enum ocelot_sb {