[PATCH net] net/mlx5: Fix setting of irq->map.index for static IRQ case

From: Niklas Schnelle
Date: Tue May 30 2023 - 10:14:14 EST

When dynamic IRQ allocation is not supported all IRQs are allocated up
front in mlx5_irq_table_create() instead of dynamically as part of
mlx5_irq_alloc(). In the latter dynamic case irq->map.index is set
via the mapping returned by pci_msix_alloc_irq_at(). In the static case
and prior to commit 1da438c0ae02 ("net/mlx5: Fix indexing of mlx5_irq")
irq->map.index was set in mlx4_irq_alloc() twice once initially to 0 and
then to the requested index before storing in the xarray. After this
commit it is only set to 0 which breaks all other IRQ mappins.

Fix this by setting irq->map.index to the requested index together with
irq->map.virq and improve the related comment to make it clearer which
cases it deals with.

Fixes: 1da438c0ae02 ("net/mlx5: Fix indexing of mlx5_irq")
Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
index db5687d9fec9..fd5b43e8f3bb 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
@@ -232,12 +232,13 @@ struct mlx5_irq *mlx5_irq_alloc(struct mlx5_irq_pool *pool, int i,
if (!irq)
return ERR_PTR(-ENOMEM);
if (!i || !pci_msix_can_alloc_dyn(dev->pdev)) {
- /* The vector at index 0 was already allocated.
- * Just get the irq number. If dynamic irq is not supported
- * vectors have also been allocated.
+ /* The vector at index 0 is always statically allocated. If
+ * dynamic irq is not supported all vectors are statically
+ * allocated. In both cases just get the irq number and set
+ * the index.
irq->map.virq = pci_irq_vector(dev->pdev, i);
- irq->map.index = 0;
+ irq->map.index = i;
} else {
irq->map = pci_msix_alloc_irq_at(dev->pdev, MSI_ANY_INDEX, af_desc);
if (!irq->map.virq) {