Re: [PATCH v1 14/14] net/mlx4: Use irq_update_affinity_hint

On Mon, Jun 21, 2021 at 4:02 AM Leon Romanovsky [off-list ref] wrote:

On Thu, Jun 17, 2021 at 02:22:42PM -0400, Nitesh Narayan Lal wrote:

quoted

The driver uses irq_set_affinity_hint() to update the affinity_hint mask
that is consumed by the userspace to distribute the interrupts. However,
under the hood irq_set_affinity_hint() also applies the provided cpumask
(if not NULL) as the affinity for the given interrupt which is an
undocumented side effect.

To remove this side effect irq_set_affinity_hint() has been marked
as deprecated and new interfaces have been introduced. Hence, replace the
irq_set_affinity_hint() with the new interface irq_update_affinity_hint()
that only updates the affinity_hint pointer.

Signed-off-by: Nitesh Narayan Lal <redacted>
---
 drivers/net/ethernet/mellanox/mlx4/eq.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/eq.c b/drivers/net/ethernet/mellanox/mlx4/eq.c
index 9e48509ed3b2..f549d697ca95 100644
--- a/drivers/net/ethernet/mellanox/mlx4/eq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/eq.c

@@ -244,9 +244,9 @@ static void mlx4_set_eq_affinity_hint(struct mlx4_priv *priv, int vec)
          cpumask_empty(eq->affinity_mask))
              return;

-     hint_err = irq_set_affinity_hint(eq->irq, eq->affinity_mask);
+     hint_err = irq_update_affinity_hint(eq->irq, eq->affinity_mask);
      if (hint_err)
-             mlx4_warn(dev, "irq_set_affinity_hint failed, err %d\n", hint_err);
+             mlx4_warn(dev, "irq_update_affinity_hint failed, err %d\n", hint_err);
 }
 #endif

@@ -1124,7 +1124,7 @@ static void mlx4_free_irqs(struct mlx4_dev *dev)
              if (eq_table->eq[i].have_irq) {
                      free_cpumask_var(eq_table->eq[i].affinity_mask);
 #if defined(CONFIG_SMP)
-                     irq_set_affinity_hint(eq_table->eq[i].irq, NULL);
+                     irq_update_affinity_hint(eq_table->eq[i].irq, NULL);
 #endif

This #if/endif can be deleted.

I think we also can get rid of the other #if/endif CONFIG_SMP
occurrences that are present around mlx4_set_eq_affinity_hint()
definition and call, isn't it?
There is already a check-in interrupt.h so doing it again in the
driver looks like an unwanted repetition IMHO.

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

-- 
Thanks
Nitesh