This is a note to let you know that I've just added the patch titled net/mlx5: DR, No need for atomic refcount for internal SW steering resources to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-mlx5-dr-no-need-for-atomic-refcount-for-internal-sw-steering-resources.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat 11 Jan 2020 09:13:20 AM CET From: Yevgeny Kliteynik <kliteyn@xxxxxxxxxxxx> Date: Mon, 23 Dec 2019 16:16:31 +0200 Subject: net/mlx5: DR, No need for atomic refcount for internal SW steering resources From: Yevgeny Kliteynik <kliteyn@xxxxxxxxxxxx> [ Upstream commit 4ce380ca477507e2f413584cdd99e1698d6682d6 ] 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@xxxxxxxxxxxx> Reviewed-by: Alex Vesker <valex@xxxxxxxxxxxx> Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -340,7 +340,7 @@ 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); @@ -557,7 +557,7 @@ 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 */ @@ -681,14 +681,14 @@ 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); @@ -705,7 +705,7 @@ 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 @@ -117,7 +117,7 @@ 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; @@ -149,7 +149,7 @@ 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; @@ -200,13 +200,14 @@ 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 */ @@ -248,14 +249,15 @@ 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, Patches currently in stable-queue which might be from kliteyn@xxxxxxxxxxxx are queue-5.4/net-mlx5-dr-no-need-for-atomic-refcount-for-internal-sw-steering-resources.patch