net: mscc: ocelot: turn stats_lock into a spinlock

ocelot_get_stats64() currently runs unlocked and therefore may collide
with ocelot_port_update_stats() which indirectly accesses the same
counters. However, ocelot_get_stats64() runs in atomic context, and we
cannot simply take the sleepable ocelot->stats_lock mutex. We need to
convert it to an atomic spinlock first. Do that as a preparatory change.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index e1ebe21cad0078752a5de94ccff11f78224df61a..46fd6cd0d8f3df1e9c852979f659b72309de97d2 100644 (file)
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -2171,7 +2171,7 @@ 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);
+       spin_lock(&ocelot->stats_lock);
 
        ocelot_rmw(ocelot, SYS_STAT_CFG_STAT_VIEW(index),
                   SYS_STAT_CFG_STAT_VIEW_M,
@@ -2188,7 +2188,7 @@ static void vsc9959_psfp_counters_get(struct ocelot *ocelot, u32 index,
                     SYS_STAT_CFG_STAT_CLEAR_SHOT(0x10),
                     SYS_STAT_CFG);
 
-       mutex_unlock(&ocelot->stats_lock);
+       spin_unlock(&ocelot->stats_lock);
 }
 
 static int vsc9959_psfp_filter_add(struct ocelot *ocelot, int port,

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index d4649e4ee0e7ff4a58d435bd18fed0887f43fdc7..c67f162f8ab5e0169e995c51c7cfe1c611fdff6c 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1906,13 +1906,13 @@ static void ocelot_check_stats_work(struct work_struct *work)
                                             stats_work);
        int i, err;
 
-       mutex_lock(&ocelot->stats_lock);
+       spin_lock(&ocelot->stats_lock);
        for (i = 0; i < ocelot->num_phys_ports; i++) {
                err = ocelot_port_update_stats(ocelot, i);
                if (err)
                        break;
        }
-       mutex_unlock(&ocelot->stats_lock);
+       spin_unlock(&ocelot->stats_lock);
 
        if (err)
                dev_err(ocelot->dev, "Error %d updating ethtool stats\n",  err);
@@ -1925,7 +1925,7 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data)
 {
        int i, err;
 
-       mutex_lock(&ocelot->stats_lock);
+       spin_lock(&ocelot->stats_lock);
 
        /* check and update now */
        err = ocelot_port_update_stats(ocelot, port);
@@ -1934,7 +1934,7 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data)
        for (i = 0; i < ocelot->num_stats; i++)
                *data++ = ocelot->stats[port * ocelot->num_stats + i];
 
-       mutex_unlock(&ocelot->stats_lock);
+       spin_unlock(&ocelot->stats_lock);
 
        if (err)
                dev_err(ocelot->dev, "Error %d updating ethtool stats\n", err);
@@ -3363,7 +3363,7 @@ int ocelot_init(struct ocelot *ocelot)
        if (!ocelot->stats)
                return -ENOMEM;
 
-       mutex_init(&ocelot->stats_lock);
+       spin_lock_init(&ocelot->stats_lock);
        mutex_init(&ocelot->ptp_lock);
        mutex_init(&ocelot->mact_lock);
        mutex_init(&ocelot->fwd_domain_lock);
@@ -3511,7 +3511,6 @@ void ocelot_deinit(struct ocelot *ocelot)
        cancel_delayed_work(&ocelot->stats_work);
        destroy_workqueue(ocelot->stats_queue);
        destroy_workqueue(ocelot->owq);
-       mutex_destroy(&ocelot->stats_lock);
 }
 EXPORT_SYMBOL(ocelot_deinit);
 

diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index e7e5b06deb2d84f72726feda518728338ca5553e..72b9474391da3783a99ed1ae77139ae20eaebd0e 100644 (file)
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -752,7 +752,7 @@ struct ocelot {
        struct ocelot_psfp_list         psfp;
 
        /* Workqueue to check statistics for overflow with its lock */
-       struct mutex                    stats_lock;
+       spinlock_t                      stats_lock;
        u64                             *stats;
        struct delayed_work             stats_work;
        struct workqueue_struct         *stats_queue;