net/mlx5e: xsk: Use queue indices starting from 0 for XSK queues

In the initial implementation of XSK in mlx5e, XSK RQs coexisted with
regular RQs in the same channel. The main idea was to allow RSS work the
same for regular traffic, without need to reconfigure RSS to exclude XSK
queues.

However, this scheme didn't prove to be beneficial, mainly because of
incompatibility with other vendors. Some tools don't properly support
using higher indices for XSK queues, some tools get confused with the
double amount of RQs exposed in sysfs. Some use cases are purely XSK,
and allocating the same amount of unused regular RQs is a waste of
resources.

This commit changes the queuing scheme to the standard one, where XSK
RQs replace regular RQs on the channels where XSK sockets are open. Two
RQs still exist in the channel to allow failsafe disable of XSK, but
only one is exposed at a time. The next commit will achieve the desired
memory save by flushing the buffers when the regular RQ is unused.

As the result of this transition:

1. It's possible to use RSS contexts over XSK RQs.

2. It's possible to dedicate all queues to XSK.

3. When XSK RQs coexist with regular RQs, the admin should make sure no
unwanted traffic goes into XSK RQs by either excluding them from RSS or
settings up the XDP program to return XDP_PASS for non-XSK traffic.

4. When using a mixed fleet of mlx5e devices and other netdevs, the same
configuration can be applied. If the application supports the fallback
to copy mode on unsupported drivers, it will work too.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 15 insertions, 103 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/rx_res.c b/drivers/net/ethernet/mellanox/mlx5/core/en/rx_res.c
index 3436ecfcbc2f..e1095bc36543 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rx_res.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rx_res.c
@@ -24,8 +24,6 @@ struct mlx5e_rx_res {
 	struct {
 		struct mlx5e_rqt direct_rqt;
 		struct mlx5e_tir direct_tir;
-		struct mlx5e_rqt xsk_rqt;
-		struct mlx5e_tir xsk_tir;
 	} *channels;
 
 	struct {
@@ -320,48 +318,8 @@ static int mlx5e_rx_res_channels_init(struct mlx5e_rx_res *res)
 		mlx5e_tir_builder_clear(builder);
 	}
 
-	if (!(res->features & MLX5E_RX_RES_FEATURE_XSK))
-		goto out;
-
-	for (ix = 0; ix < res->max_nch; ix++) {
-		err = mlx5e_rqt_init_direct(&res->channels[ix].xsk_rqt,
-					    res->mdev, false, res->drop_rqn);
-		if (err) {
-			mlx5_core_warn(res->mdev, "Failed to create an XSK RQT: err = %d, ix = %u\n",
-				       err, ix);
-			goto err_destroy_xsk_rqts;
-		}
-	}
-
-	for (ix = 0; ix < res->max_nch; ix++) {
-		mlx5e_tir_builder_build_rqt(builder, res->mdev->mlx5e_res.hw_objs.td.tdn,
-					    mlx5e_rqt_get_rqtn(&res->channels[ix].xsk_rqt),
-					    inner_ft_support);
-		mlx5e_tir_builder_build_packet_merge(builder, &res->pkt_merge_param);
-		mlx5e_tir_builder_build_direct(builder);
-
-		err = mlx5e_tir_init(&res->channels[ix].xsk_tir, builder, res->mdev, true);
-		if (err) {
-			mlx5_core_warn(res->mdev, "Failed to create an XSK TIR: err = %d, ix = %u\n",
-				       err, ix);
-			goto err_destroy_xsk_tirs;
-		}
-
-		mlx5e_tir_builder_clear(builder);
-	}
-
 	goto out;
 
-err_destroy_xsk_tirs:
-	while (--ix >= 0)
-		mlx5e_tir_destroy(&res->channels[ix].xsk_tir);
-
-	ix = res->max_nch;
-err_destroy_xsk_rqts:
-	while (--ix >= 0)
-		mlx5e_rqt_destroy(&res->channels[ix].xsk_rqt);
-
-	ix = res->max_nch;
 err_destroy_direct_tirs:
 	while (--ix >= 0)
 		mlx5e_tir_destroy(&res->channels[ix].direct_tir);
@@ -420,12 +378,6 @@ static void mlx5e_rx_res_channels_destroy(struct mlx5e_rx_res *res)
 	for (ix = 0; ix < res->max_nch; ix++) {
 		mlx5e_tir_destroy(&res->channels[ix].direct_tir);
 		mlx5e_rqt_destroy(&res->channels[ix].direct_rqt);
-
-		if (!(res->features & MLX5E_RX_RES_FEATURE_XSK))
-			continue;
-
-		mlx5e_tir_destroy(&res->channels[ix].xsk_tir);
-		mlx5e_rqt_destroy(&res->channels[ix].xsk_rqt);
 	}
 
 	kvfree(res->channels);
@@ -491,13 +443,6 @@ u32 mlx5e_rx_res_get_tirn_direct(struct mlx5e_rx_res *res, unsigned int ix)
 	return mlx5e_tir_get_tirn(&res->channels[ix].direct_tir);
 }
 
-u32 mlx5e_rx_res_get_tirn_xsk(struct mlx5e_rx_res *res, unsigned int ix)
-{
-	WARN_ON(!(res->features & MLX5E_RX_RES_FEATURE_XSK));
-
-	return mlx5e_tir_get_tirn(&res->channels[ix].xsk_tir);
-}
-
 u32 mlx5e_rx_res_get_tirn_rss(struct mlx5e_rx_res *res, enum mlx5_traffic_types tt)
 {
 	struct mlx5e_rss *rss = res->rss[0];
@@ -527,26 +472,14 @@ static void mlx5e_rx_res_channel_activate_direct(struct mlx5e_rx_res *res,
 						 struct mlx5e_channels *chs,
 						 unsigned int ix)
 {
-	u32 rqn;
+	u32 rqn = res->rss_rqns[ix];
 	int err;
 
-	mlx5e_channels_get_regular_rqn(chs, ix, &rqn);
 	err = mlx5e_rqt_redirect_direct(&res->channels[ix].direct_rqt, rqn);
 	if (err)
 		mlx5_core_warn(res->mdev, "Failed to redirect direct RQT %#x to RQ %#x (channel %u): err = %d\n",
 			       mlx5e_rqt_get_rqtn(&res->channels[ix].direct_rqt),
 			       rqn, ix, err);
-
-	if (!(res->features & MLX5E_RX_RES_FEATURE_XSK))
-		return;
-
-	if (!mlx5e_channels_get_xsk_rqn(chs, ix, &rqn))
-		rqn = res->drop_rqn;
-	err = mlx5e_rqt_redirect_direct(&res->channels[ix].xsk_rqt, rqn);
-	if (err)
-		mlx5_core_warn(res->mdev, "Failed to redirect XSK RQT %#x to RQ %#x (channel %u): err = %d\n",
-			       mlx5e_rqt_get_rqtn(&res->channels[ix].xsk_rqt),
-			       rqn, ix, err);
 }
 
 static void mlx5e_rx_res_channel_deactivate_direct(struct mlx5e_rx_res *res,
@@ -559,15 +492,6 @@ static void mlx5e_rx_res_channel_deactivate_direct(struct mlx5e_rx_res *res,
 		mlx5_core_warn(res->mdev, "Failed to redirect direct RQT %#x to drop RQ %#x (channel %u): err = %d\n",
 			       mlx5e_rqt_get_rqtn(&res->channels[ix].direct_rqt),
 			       res->drop_rqn, ix, err);
-
-	if (!(res->features & MLX5E_RX_RES_FEATURE_XSK))
-		return;
-
-	err = mlx5e_rqt_redirect_direct(&res->channels[ix].xsk_rqt, res->drop_rqn);
-	if (err)
-		mlx5_core_warn(res->mdev, "Failed to redirect XSK RQT %#x to drop RQ %#x (channel %u): err = %d\n",
-			       mlx5e_rqt_get_rqtn(&res->channels[ix].xsk_rqt),
-			       res->drop_rqn, ix, err);
 }
 
 void mlx5e_rx_res_channels_activate(struct mlx5e_rx_res *res, struct mlx5e_channels *chs)
@@ -577,8 +501,12 @@ void mlx5e_rx_res_channels_activate(struct mlx5e_rx_res *res, struct mlx5e_chann
 
 	nch = mlx5e_channels_get_num(chs);
 
-	for (ix = 0; ix < chs->num; ix++)
-		mlx5e_channels_get_regular_rqn(chs, ix, &res->rss_rqns[ix]);
+	for (ix = 0; ix < chs->num; ix++) {
+		if (mlx5e_channels_is_xsk(chs, ix))
+			mlx5e_channels_get_xsk_rqn(chs, ix, &res->rss_rqns[ix]);
+		else
+			mlx5e_channels_get_regular_rqn(chs, ix, &res->rss_rqns[ix]);
+	}
 	res->rss_nch = chs->num;
 
 	mlx5e_rx_res_rss_enable(res);
@@ -621,33 +549,17 @@ void mlx5e_rx_res_channels_deactivate(struct mlx5e_rx_res *res)
 	}
 }
 
-int mlx5e_rx_res_xsk_activate(struct mlx5e_rx_res *res, struct mlx5e_channels *chs,
-			      unsigned int ix)
+void mlx5e_rx_res_xsk_update(struct mlx5e_rx_res *res, struct mlx5e_channels *chs,
+			     unsigned int ix, bool xsk)
 {
-	u32 rqn;
-	int err;
-
-	if (!mlx5e_channels_get_xsk_rqn(chs, ix, &rqn))
-		return -EINVAL;
-
-	err = mlx5e_rqt_redirect_direct(&res->channels[ix].xsk_rqt, rqn);
-	if (err)
-		mlx5_core_warn(res->mdev, "Failed to redirect XSK RQT %#x to XSK RQ %#x (channel %u): err = %d\n",
-			       mlx5e_rqt_get_rqtn(&res->channels[ix].xsk_rqt),
-			       rqn, ix, err);
-	return err;
-}
+	if (xsk)
+		mlx5e_channels_get_xsk_rqn(chs, ix, &res->rss_rqns[ix]);
+	else
+		mlx5e_channels_get_regular_rqn(chs, ix, &res->rss_rqns[ix]);
 
-int mlx5e_rx_res_xsk_deactivate(struct mlx5e_rx_res *res, unsigned int ix)
-{
-	int err;
+	mlx5e_rx_res_rss_enable(res);
 
-	err = mlx5e_rqt_redirect_direct(&res->channels[ix].xsk_rqt, res->drop_rqn);
-	if (err)
-		mlx5_core_warn(res->mdev, "Failed to redirect XSK RQT %#x to drop RQ %#x (channel %u): err = %d\n",
-			       mlx5e_rqt_get_rqtn(&res->channels[ix].xsk_rqt),
-			       res->drop_rqn, ix, err);
-	return err;
+	mlx5e_rx_res_channel_activate_direct(res, chs, ix);
 }
 
 int mlx5e_rx_res_packet_merge_set_param(struct mlx5e_rx_res *res,