Re: [PATCH net-next 3/3] net/mlx4_core: Use msi_x module param to limit num of MSI-X irqs

[Ajaykumar Hotchandani]

Thanks Tariq.

Reviewed-by: Ajaykumar Hotchandani <ajaykumar.hotchand...@oracle.com>

On 05/09/2018 08:29 AM, Tariq Toukan wrote:

Extend the boolean interpretation of msi_x module parameter
to numerical, as follows:

0   - Don't use MSI-X.
1   - Use MSI-X, driver decides the num of MSI-X irqs.

=2 - Use MSI-X, limit number of MSI-X irqs to msi_x.

       In SRIOV, this limits the number of MSI-X irqs per VF.

Signed-off-by: Tariq Toukan <tar...@mellanox.com>
Cc: Ajaykumar Hotchandani <ajaykumar.hotchand...@oracle.com>
---
  drivers/net/ethernet/mellanox/mlx4/main.c | 10 +++++++++-
  1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c 
b/drivers/net/ethernet/mellanox/mlx4/main.c
index b6aaf34d6648..80a75c80a463 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -73,7 +73,7 @@

static int msi_x = 1;

  module_param(msi_x, int, 0444);
-MODULE_PARM_DESC(msi_x, "attempt to use MSI-X if nonzero");
+MODULE_PARM_DESC(msi_x, "0 - don't use MSI-X, 1 - use MSI-X, >1 - limit number of 
MSI-X irqs to msi_x");

#else /* CONFIG_PCI_MSI */ @@ -2815,6 +2815,9 @@ static void mlx4_enable_msi_x(struct mlx4_dev *dev)

                                dev->caps.num_eqs - dev->caps.reserved_eqs,
                                MAX_MSIX);

+ if (msi_x > 1)

+                       nreq = min_t(int, nreq, msi_x);
+
                entries = kcalloc(nreq, sizeof(*entries), GFP_KERNEL);
                if (!entries)
                        goto no_msi;
@@ -4182,6 +4185,11 @@ static int mlx4_resume(struct pci_dev *pdev)

static int __init mlx4_verify_params(void)

  {
+       if (msi_x < 0) {
+               pr_warn("mlx4_core: bad msi_x: %d\n", msi_x);
+               return -1;
+       }
+
        if ((log_num_mac < 0) || (log_num_mac > 7)) {
                pr_warn("mlx4_core: bad num_mac: %d\n", log_num_mac);
                return -1;