netdev - [net 7/9] net/mlx5: Don't request more than supported EQs

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Date:   Wed, 31 Mar 2021 13:14:22 -0700
From:   Saeed Mahameed <saeed@...nel.org>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, Tariq Toukan <tariqt@...dia.com>,
        Daniel Jurgens <danielj@...lanox.com>,
        Parav Pandit <parav@...dia.com>,
        Saeed Mahameed <saeedm@...dia.com>
Subject: [net 7/9] net/mlx5: Don't request more than supported EQs

From: Daniel Jurgens <danielj@...lanox.com>

Calculating the number of compeltion EQs based on the number of
available IRQ vectors doesn't work now that all async EQs share one IRQ.
Thus the max number of EQs can be exceeded on systems with more than
approximately 256 CPUs. Take this into account when calculating the
number of available completion EQs.

Fixes: 81bfa206032a ("net/mlx5: Use a single IRQ for all async EQs")
Signed-off-by: Daniel Jurgens <danielj@...lanox.com>
Reviewed-by: Parav Pandit <parav@...dia.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/eq.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eq.c b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
index 174dfbc996c6..1fa9c18563da 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
@@ -931,13 +931,24 @@ void mlx5_core_eq_free_irqs(struct mlx5_core_dev *dev)
 	mutex_unlock(&table->lock);
 }
 
+#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
+#define MLX5_MAX_ASYNC_EQS 4
+#else
+#define MLX5_MAX_ASYNC_EQS 3
+#endif
+
 int mlx5_eq_table_create(struct mlx5_core_dev *dev)
 {
 	struct mlx5_eq_table *eq_table = dev->priv.eq_table;
+	int num_eqs = MLX5_CAP_GEN(dev, max_num_eqs) ?
+		      MLX5_CAP_GEN(dev, max_num_eqs) :
+		      1 << MLX5_CAP_GEN(dev, log_max_eq);
 	int err;
 
 	eq_table->num_comp_eqs =
-		mlx5_irq_get_num_comp(eq_table->irq_table);
+		min_t(int,
+		      mlx5_irq_get_num_comp(eq_table->irq_table),
+		      num_eqs - MLX5_MAX_ASYNC_EQS);
 
 	err = create_async_eqs(dev);
 	if (err) {
-- 
2.30.2