[PATCH 4.16 51/55] net/mlx5: Fix mlx5_get_vector_affinity function

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Israel Rukshin <israelr@mellanox.com>

[ Upstream commit 6082d9c9c94a408d7409b5f2e4e42ac9e8b16d0d ]

Adding the vector offset when calling to mlx5_vector2eqn() is wrong.
This is because mlx5_vector2eqn() checks if EQ index is equal to vector number
and the fact that the internal completion vectors that mlx5 allocates
don't get an EQ index.

The second problem here is that using effective_affinity_mask gives the same
CPU for different vectors.
This leads to unmapped queues when calling it from blk_mq_rdma_map_queues().
This doesn't happen when using affinity_hint mask.

Fixes: 2572cf57d75a ("mlx5: fix mlx5_get_vector_affinity to start from completion vector 0")
Fixes: 05e0cc84e00c ("net/mlx5: Fix get vector affinity helper function")
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/infiniband/hw/mlx5/main.c |    2 +-
 include/linux/mlx5/driver.h       |   12 +++---------
 2 files changed, 4 insertions(+), 10 deletions(-)

--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -4303,7 +4303,7 @@ mlx5_ib_get_vector_affinity(struct ib_de
 {
 	struct mlx5_ib_dev *dev = to_mdev(ibdev);
 
-	return mlx5_get_vector_affinity(dev->mdev, comp_vector);
+	return mlx5_get_vector_affinity_hint(dev->mdev, comp_vector);
 }
 
 /* The mlx5_ib_multiport_mutex should be held when calling this function */
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -1269,25 +1269,19 @@ enum {
 };
 
 static inline const struct cpumask *
-mlx5_get_vector_affinity(struct mlx5_core_dev *dev, int vector)
+mlx5_get_vector_affinity_hint(struct mlx5_core_dev *dev, int vector)
 {
-	const struct cpumask *mask;
 	struct irq_desc *desc;
 	unsigned int irq;
 	int eqn;
 	int err;
 
-	err = mlx5_vector2eqn(dev, MLX5_EQ_VEC_COMP_BASE + vector, &eqn, &irq);
+	err = mlx5_vector2eqn(dev, vector, &eqn, &irq);
 	if (err)
 		return NULL;
 
 	desc = irq_to_desc(irq);
-#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
-	mask = irq_data_get_effective_affinity_mask(&desc->irq_data);
-#else
-	mask = desc->irq_common_data.affinity;
-#endif
-	return mask;
+	return desc->affinity_hint;
 }
 
 #endif /* MLX5_DRIVER_H */