From: Yevgeny Kliteynik <kliteyn@mellanox.com>
Date: Mon, 23 Dec 2019 16:16:31 +0200
Subject: net/mlx5: DR, No need for atomic refcount for internal SW steering
 resources
Patch-mainline: v5.5-rc6
Git-commit: 4ce380ca477507e2f413584cdd99e1698d6682d6
References: jsc#SLE-8464

No need for an atomic refcounter for the STE and hashtables.
These are internal SW steering resources and they are always
under domain mutex.

This also fixes the following refcount error:
  refcount_t: addition on 0; use-after-free.
  WARNING: CPU: 9 PID: 3527 at lib/refcount.c:25 refcount_warn_saturate+0x81/0xe0
  Call Trace:
   dr_table_init_nic+0x10d/0x110 [mlx5_core]
   mlx5dr_table_create+0xb4/0x230 [mlx5_core]
   mlx5_cmd_dr_create_flow_table+0x39/0x120 [mlx5_core]
   __mlx5_create_flow_table+0x221/0x5f0 [mlx5_core]
   esw_create_offloads_fdb_tables+0x180/0x5a0 [mlx5_core]
   ...

Fixes: 26d688e33f88 ("net/mlx5: DR, Add Steering entry (STE) utilities")
Signed-off-by: Yevgeny Kliteynik <kliteyn@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c  |    2 -
 drivers/net/ethernet/mellanox/mlx5/core/steering/dr_ste.c   |   10 ++++----
 drivers/net/ethernet/mellanox/mlx5/core/steering/dr_types.h |   14 ++++++------
 3 files changed, 14 insertions(+), 12 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
@@ -209,7 +209,7 @@ static void dr_rule_rehash_copy_ste_ctrl
 	/* We need to copy the refcount since this ste
 	 * may have been traversed several times
 	 */
-	refcount_set(&new_ste->refcount, refcount_read(&cur_ste->refcount));
+	new_ste->refcount = cur_ste->refcount;
 
 	/* Link old STEs rule_mem list to the new ste */
 	mlx5dr_rule_update_rule_member(cur_ste, new_ste);
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_ste.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_ste.c
@@ -348,7 +348,7 @@ static void dr_ste_replace(struct mlx5dr
 	if (dst->next_htbl)
 		dst->next_htbl->pointing_ste = dst;
 
-	refcount_set(&dst->refcount, refcount_read(&src->refcount));
+	dst->refcount = src->refcount;
 
 	INIT_LIST_HEAD(&dst->rule_list);
 	list_splice_tail_init(&src->rule_list, &dst->rule_list);
@@ -565,7 +565,7 @@ bool mlx5dr_ste_is_not_valid_entry(u8 *p
 
 bool mlx5dr_ste_not_used_ste(struct mlx5dr_ste *ste)
 {
-	return !refcount_read(&ste->refcount);
+	return !ste->refcount;
 }
 
 /* Init one ste as a pattern for ste data array */
@@ -689,14 +689,14 @@ struct mlx5dr_ste_htbl *mlx5dr_ste_htbl_
 	htbl->ste_arr = chunk->ste_arr;
 	htbl->hw_ste_arr = chunk->hw_ste_arr;
 	htbl->miss_list = chunk->miss_list;
-	refcount_set(&htbl->refcount, 0);
+	htbl->refcount = 0;
 
 	for (i = 0; i < chunk->num_of_entries; i++) {
 		struct mlx5dr_ste *ste = &htbl->ste_arr[i];
 
 		ste->hw_ste = htbl->hw_ste_arr + i * DR_STE_SIZE_REDUCED;
 		ste->htbl = htbl;
-		refcount_set(&ste->refcount, 0);
+		ste->refcount = 0;
 		INIT_LIST_HEAD(&ste->miss_list_node);
 		INIT_LIST_HEAD(&htbl->miss_list[i]);
 		INIT_LIST_HEAD(&ste->rule_list);
@@ -713,7 +713,7 @@ out_free_htbl:
 
 int mlx5dr_ste_htbl_free(struct mlx5dr_ste_htbl *htbl)
 {
-	if (refcount_read(&htbl->refcount))
+	if (htbl->refcount)
 		return -EBUSY;
 
 	mlx5dr_icm_free_chunk(htbl->chunk);
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_types.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_types.h
@@ -123,7 +123,7 @@ struct mlx5dr_matcher_rx_tx;
 struct mlx5dr_ste {
 	u8 *hw_ste;
 	/* refcount: indicates the num of rules that using this ste */
-	refcount_t refcount;
+	u32 refcount;
 
 	/* attached to the miss_list head at each htbl entry */
 	struct list_head miss_list_node;
@@ -155,7 +155,7 @@ struct mlx5dr_ste_htbl_ctrl {
 struct mlx5dr_ste_htbl {
 	u8 lu_type;
 	u16 byte_mask;
-	refcount_t refcount;
+	u32 refcount;
 	struct mlx5dr_icm_chunk *chunk;
 	struct mlx5dr_ste *ste_arr;
 	u8 *hw_ste_arr;
@@ -206,13 +206,14 @@ int mlx5dr_ste_htbl_free(struct mlx5dr_s
 
 static inline void mlx5dr_htbl_put(struct mlx5dr_ste_htbl *htbl)
 {
-	if (refcount_dec_and_test(&htbl->refcount))
+	htbl->refcount--;
+	if (!htbl->refcount)
 		mlx5dr_ste_htbl_free(htbl);
 }
 
 static inline void mlx5dr_htbl_get(struct mlx5dr_ste_htbl *htbl)
 {
-	refcount_inc(&htbl->refcount);
+	htbl->refcount++;
 }
 
 /* STE utils */
@@ -254,14 +255,15 @@ static inline void mlx5dr_ste_put(struct
 				  struct mlx5dr_matcher *matcher,
 				  struct mlx5dr_matcher_rx_tx *nic_matcher)
 {
-	if (refcount_dec_and_test(&ste->refcount))
+	ste->refcount--;
+	if (!ste->refcount)
 		mlx5dr_ste_free(ste, matcher, nic_matcher);
 }
 
 /* initial as 0, increased only when ste appears in a new rule */
 static inline void mlx5dr_ste_get(struct mlx5dr_ste *ste)
 {
-	refcount_inc(&ste->refcount);
+	ste->refcount++;
 }
 
 void mlx5dr_ste_set_hit_addr_by_next_htbl(u8 *hw_ste,