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From: Saeed Mahameed <saeedm@mellanox.com>
To: "David S. Miller" <davem@davemloft.net>, kuba@kernel.org
Cc: netdev@vger.kernel.org, Jiri Pirko <jiri@mellanox.com>,
	Eli Cohen <eli@mellanox.com>, Mark Bloch <markb@mellanox.com>,
	Saeed Mahameed <saeedm@mellanox.com>
Subject: [net-next 10/16] net/mlx5: Avoid group version scan when not necessary
Date: Wed, 25 Mar 2020 23:38:03 -0700
Message-ID: <20200326063809.139919-11-saeedm@mellanox.com> (raw)
In-Reply-To: <20200326063809.139919-1-saeedm@mellanox.com>

From: Eli Cohen <eli@mellanox.com>

Group version is used when modifying a rule is allowed
(FLOW_ACT_NO_APPEND is clear) to detect a case where the rule was found
but while the groups where unlocked a new FTE was added. In this case,
the added FTE could be one with identical match value so we need to
attempt again with group lock held.

Change the code so version is retrieved only when FLOW_ACT_NO_APPEND is
cleared. As result, later compare can also be avoided if FLOW_ACT_NO_APPEND
is cleared.

Also improve comments text.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
---
 .../net/ethernet/mellanox/mlx5/core/fs_core.c    | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 44ed42e0e1c7..62ce2b9417ab 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1680,7 +1680,7 @@ try_add_to_existing_fg(struct mlx5_flow_table *ft,
 	struct match_list *iter;
 	bool take_write = false;
 	struct fs_fte *fte;
-	u64  version;
+	u64  version = 0;
 	int err;
 
 	fte = alloc_fte(ft, spec, flow_act);
@@ -1688,10 +1688,12 @@ try_add_to_existing_fg(struct mlx5_flow_table *ft,
 		return  ERR_PTR(-ENOMEM);
 
 search_again_locked:
-	version = matched_fgs_get_version(match_head);
 	if (flow_act->flags & FLOW_ACT_NO_APPEND)
 		goto skip_search;
-	/* Try to find a fg that already contains a matching fte */
+	version = matched_fgs_get_version(match_head);
+	/* Try to find an fte with identical match value and attempt update its
+	 * action.
+	 */
 	list_for_each_entry(iter, match_head, list) {
 		struct fs_fte *fte_tmp;
 
@@ -1719,10 +1721,12 @@ try_add_to_existing_fg(struct mlx5_flow_table *ft,
 		goto out;
 	}
 
-	/* Check the fgs version, for case the new FTE with the
-	 * same values was added while the fgs weren't locked
+	/* Check the fgs version. If version have changed it could be that an
+	 * FTE with the same match value was added while the fgs weren't
+	 * locked.
 	 */
-	if (version != matched_fgs_get_version(match_head)) {
+	if (!(flow_act->flags & FLOW_ACT_NO_APPEND) &&
+	    version != matched_fgs_get_version(match_head)) {
 		take_write = true;
 		goto search_again_locked;
 	}
-- 
2.25.1


  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26  6:37 [pull request][net-next 00/16] Mellanox, mlx5 updates 2020-03-25 Saeed Mahameed
2020-03-26  6:37 ` [net-next 01/16] net/mlx5e: Fix actions_match_supported() return Saeed Mahameed
2020-03-26  6:37 ` [net-next 02/16] net/mlx5e: remove duplicated check chain_index in mlx5e_rep_setup_ft_cb Saeed Mahameed
2020-03-26  6:37 ` [net-next 03/16] net/mlx5: E-Switch, Enable restore table only if reg_c1 is supported Saeed Mahameed
2020-03-26  6:37 ` [net-next 04/16] net/mlx5: E-Switch, Enable chains only if regs loopback is enabled Saeed Mahameed
2020-03-26  6:37 ` [net-next 05/16] net/mlx5: E-Switch, free flow_group_in after creating the restore table Saeed Mahameed
2020-03-26  6:37 ` [net-next 06/16] net/mlx5: E-Switch, Use correct type for chain, prio and level values Saeed Mahameed
2020-03-26  6:38 ` [net-next 07/16] net/mlx5: Simplify matching group searches Saeed Mahameed
2020-03-26  6:38 ` [net-next 08/16] net/mlx5: Fix group version management Saeed Mahameed
2020-03-26  6:38 ` [net-next 09/16] net/mlx5: Avoid incrementing FTE version Saeed Mahameed
2020-03-26  6:38 ` Saeed Mahameed [this message]
2020-03-26  6:38 ` [net-next 11/16] net/mlx5: Simplify mlx5_register_device to return void Saeed Mahameed
2020-03-26  6:38 ` [net-next 12/16] net/mlx5: Simplify mlx5_unload_one() and its callers Saeed Mahameed
2020-03-26  6:38 ` [net-next 13/16] devlink: Rely on driver eswitch thread safety instead of devlink Saeed Mahameed
2020-03-26  6:38 ` [net-next 14/16] net/mlx5: Split eswitch mode check to different helper function Saeed Mahameed
2020-03-26  6:38 ` [net-next 15/16] net/mlx5: E-switch, Extend eswitch enable to handle num_vfs change Saeed Mahameed
2020-03-26  6:38 ` [net-next 16/16] net/mlx5: E-switch, Protect eswitch mode changes Saeed Mahameed
2020-03-26 18:39 ` [pull request][net-next 00/16] Mellanox, mlx5 updates 2020-03-25 David Miller

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