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From:   Niklas Schnelle <schnelle@linux.ibm.com>
To:     Shay Drory <shayd@nvidia.com>, Saeed Mahameed <saeedm@nvidia.com>,
        Eli Cohen <elic@nvidia.com>, Leon Romanovsky <leon@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org
Subject: [PATCH net] net/mlx5: Fix setting of irq->map.index for static IRQ case
Date:   Tue, 30 May 2023 16:13:04 +0200
Message-Id: <20230530141304.1850195-1-schnelle@linux.ibm.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@linux.ibm.com>
---
 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) {
-- 
2.39.2