Re: [PATCH net-next] net/mlx5: Add reset_prepare and reset_done callbacks

[Narcisa Vasile <narcisav.kernel@gmail.com>]

On Sun, Oct 11, 2026 at 12:48:09PM +0300, Tariq Toukan wrote:
> From: Akiva Goldberger <agoldberger@nvidia.com>
> 
> Currently, the mlx5_core driver registers only the error_detected,
> slot_reset and resume PCI error handlers. Add the reset_prepare and
> reset_done callbacks, which are triggered by the PCI core before and
> after a PCI reset, respectively. These callbacks let mlx5 quiesce and
> restore device resources and commands around a PCI reset, so the driver
> no longer relies on the reset happening while the device is otherwise
> idle.
> 
> Additionally, add a device flag to indicate when a PCI reset is in
> progress to serialize PCI reset flows with other reset flows, namely FW
> reset. This flag also indicates to the reset_prepare and reset_done
> callbacks when to do a full unload/reload of the driver. When the
> callbacks are triggered by the hot-reset FW reset method, they leave the
> teardown and reload to the FW reset.
> 
> Signed-off-by: Akiva Goldberger <agoldberger@nvidia.com>
> Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---
>  
> +static void mlx5_pci_reset_prepare(struct pci_dev *pdev)
> +{
> +	mlx5_drain_health_wq(dev);
> +	mlx5_unload_one(dev, false);
> +	mlx5_pci_disable_device(dev);
This disables bus-mastering, after which pci_save_state snapshots it in
the disabled state. reset_done() re-enables it but the snapshot remains
stale.

If a FW error later triggers the sw recovery through mlx5_pci_slot_reset(),
the stale snapshot is re-applied with pci_restore_state().
Would this disable bus mastering again and block the driver recovery?
Should pci_set_master(pdev); and pci_restore_state(pdev); be reordered
in mlx5_pci_slot_reset()?
> +}
> +
> +static void mlx5_pci_reset_done(struct pci_dev *pdev)
> +{
> +	err = mlx5_pci_enable_device(dev);
> +	if (err) {
> +		mlx5_core_err(dev, "%s: mlx5_pci_enable_device failed, err = %d\n",
> +			      __func__, err);
nit: mlx5_core_err already prints __func__
> +		goto clear_pci_reset_flag;
> +	}