netdev - [PATCH net 1/8] net/mlx5: HWS, removed wrong access to a number of rules variable

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Message-ID: <20241015093208.197603-2-tariqt@nvidia.com>
Date: Tue, 15 Oct 2024 12:32:01 +0300
From: Tariq Toukan <tariqt@...dia.com>
To: "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>, Eric Dumazet <edumazet@...gle.com>
CC: <netdev@...r.kernel.org>, Saeed Mahameed <saeedm@...dia.com>, Gal Pressman
	<gal@...dia.com>, Leon Romanovsky <leonro@...dia.com>, Yevgeny Kliteynik
	<kliteyn@...dia.com>, kernel test robot <lkp@...el.com>, Itamar Gozlan
	<igozlan@...dia.com>, Tariq Toukan <tariqt@...dia.com>
Subject: [PATCH net 1/8] net/mlx5: HWS, removed wrong access to a number of rules variable

From: Yevgeny Kliteynik <kliteyn@...dia.com>

Removed wrong access to the num_of_rules field of the matcher.
This is a usual u32 variable, but the access was as if it was atomic.

This fixes the following CI warnings:
  mlx5hws_bwc.c:708:17: warning: large atomic operation may incur significant performance penalty;
  the access size (4 bytes) exceeds the max lock-free size (0 bytes) [-Watomic-alignment]

Fixes: 510f9f61a112 ("net/mlx5: HWS, added API and enabled HWS support")
Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202409291101.6NdtMFVC-lkp@intel.com/
Signed-off-by: Yevgeny Kliteynik <kliteyn@...dia.com>
Reviewed-by: Itamar Gozlan <igozlan@...dia.com>
Signed-off-by: Tariq Toukan <tariqt@...dia.com>
---
 .../ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c    | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c
index bd52b05db367..8f3a6f9d703d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c
@@ -691,7 +691,6 @@ static int hws_bwc_matcher_move(struct mlx5hws_bwc_matcher *bwc_matcher)
 static int
 hws_bwc_matcher_rehash_size(struct mlx5hws_bwc_matcher *bwc_matcher)
 {
-	u32 num_of_rules;
 	int ret;
 
 	/* If the current matcher size is already at its max size, we can't
@@ -705,8 +704,7 @@ hws_bwc_matcher_rehash_size(struct mlx5hws_bwc_matcher *bwc_matcher)
 	 * Need to check again if we really need rehash.
 	 * If the reason for rehash was size, but not any more - skip rehash.
 	 */
-	num_of_rules = __atomic_load_n(&bwc_matcher->num_of_rules, __ATOMIC_RELAXED);
-	if (!hws_bwc_matcher_rehash_size_needed(bwc_matcher, num_of_rules))
+	if (!hws_bwc_matcher_rehash_size_needed(bwc_matcher, bwc_matcher->num_of_rules))
 		return 0;
 
 	/* Now we're done all the checking - do the rehash:
-- 
2.44.0