mlxsw: spectrum_span: Use 'refcount_t' for reference counting

'refcount_t' is very useful for catching over/under flows. Convert the
SPAN agent objects to use it instead of 'int' for their reference count.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c
index 14c5edc71239d8fab64649da67965cc883ad93f6..235556be58f5fc9dc3de4bb14e9f6d67262aa354 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c
@@ -3,6 +3,7 @@
 
 #include <linux/if_bridge.h>
 #include <linux/list.h>
+#include <linux/refcount.h>
 #include <linux/rtnetlink.h>
 #include <linux/workqueue.h>
 #include <net/arp.h>
@@ -664,7 +665,7 @@ mlxsw_sp_span_entry_create(struct mlxsw_sp *mlxsw_sp,
 
        /* find a free entry to use */
        for (i = 0; i < mlxsw_sp->span->entries_count; i++) {
-               if (!mlxsw_sp->span->entries[i].ref_count) {
+               if (!refcount_read(&mlxsw_sp->span->entries[i].ref_count)) {
                        span_entry = &mlxsw_sp->span->entries[i];
                        break;
                }
@@ -674,7 +675,7 @@ mlxsw_sp_span_entry_create(struct mlxsw_sp *mlxsw_sp,
 
        atomic_inc(&mlxsw_sp->span->active_entries_count);
        span_entry->ops = ops;
-       span_entry->ref_count = 1;
+       refcount_set(&span_entry->ref_count, 1);
        span_entry->to_dev = to_dev;
        mlxsw_sp_span_entry_configure(mlxsw_sp, span_entry, sparms);
 
@@ -697,7 +698,7 @@ mlxsw_sp_span_entry_find_by_port(struct mlxsw_sp *mlxsw_sp,
        for (i = 0; i < mlxsw_sp->span->entries_count; i++) {
                struct mlxsw_sp_span_entry *curr = &mlxsw_sp->span->entries[i];
 
-               if (curr->ref_count && curr->to_dev == to_dev)
+               if (refcount_read(&curr->ref_count) && curr->to_dev == to_dev)
                        return curr;
        }
        return NULL;
@@ -718,7 +719,7 @@ mlxsw_sp_span_entry_find_by_id(struct mlxsw_sp *mlxsw_sp, int span_id)
        for (i = 0; i < mlxsw_sp->span->entries_count; i++) {
                struct mlxsw_sp_span_entry *curr = &mlxsw_sp->span->entries[i];
 
-               if (curr->ref_count && curr->id == span_id)
+               if (refcount_read(&curr->ref_count) && curr->id == span_id)
                        return curr;
        }
        return NULL;
@@ -735,7 +736,7 @@ mlxsw_sp_span_entry_get(struct mlxsw_sp *mlxsw_sp,
        span_entry = mlxsw_sp_span_entry_find_by_port(mlxsw_sp, to_dev);
        if (span_entry) {
                /* Already exists, just take a reference */
-               span_entry->ref_count++;
+               refcount_inc(&span_entry->ref_count);
                return span_entry;
        }
 
@@ -745,8 +746,7 @@ mlxsw_sp_span_entry_get(struct mlxsw_sp *mlxsw_sp,
 static int mlxsw_sp_span_entry_put(struct mlxsw_sp *mlxsw_sp,
                                   struct mlxsw_sp_span_entry *span_entry)
 {
-       WARN_ON(!span_entry->ref_count);
-       if (--span_entry->ref_count == 0)
+       if (refcount_dec_and_test(&span_entry->ref_count))
                mlxsw_sp_span_entry_destroy(mlxsw_sp, span_entry);
        return 0;
 }
@@ -1018,7 +1018,7 @@ static void mlxsw_sp_span_respin_work(struct work_struct *work)
                struct mlxsw_sp_span_entry *curr = &mlxsw_sp->span->entries[i];
                struct mlxsw_sp_span_parms sparms = {NULL};
 
-               if (!curr->ref_count)
+               if (!refcount_read(&curr->ref_count))
                        continue;
 
                err = curr->ops->parms_set(curr->to_dev, &sparms);

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.h b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.h
index 01273e54ba2062501f58e0c86749455d6b337a2e..d23abdf957fa221c7d177b1d4f99ff3c228e267b 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_span.h
@@ -6,6 +6,7 @@
 
 #include <linux/types.h>
 #include <linux/if_ether.h>
+#include <linux/refcount.h>
 
 #include "spectrum_router.h"
 
@@ -43,7 +44,7 @@ struct mlxsw_sp_span_entry {
        const struct mlxsw_sp_span_entry_ops *ops;
        struct mlxsw_sp_span_parms parms;
        struct list_head bound_ports_list;
-       int ref_count;
+       refcount_t ref_count;
        int id;
 };