Re: [PATCH v4 11/25] dmaengine: sdxi: Start functions on probe, stop on remove

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] dmaengine: sdxi: PF stopped before pci_disable_sriov() in sdxi_pci_remove()
--

commit 44d5d7973859c1db8741ba90d53413150ded9a60
Author: Nathan Lynch <nathan.lynch@amd.com>

dmaengine: sdxi: Start functions on probe, stop on remove

This commit activates the SDXI function during device registration by
setting MMIO_CTL0.fn_gsr to GSRV_ACTIVE and polling for GSV_ACTIVE or
GSV_ERROR, and stops the function via sdxi_unregister() on PCI removal.

> diff --git a/drivers/dma/sdxi/pci.c b/drivers/dma/sdxi/pci.c
> index 6a293db69199f..d196ab5cf6f1c 100644
> --- a/drivers/dma/sdxi/pci.c
> +++ b/drivers/dma/sdxi/pci.c
> @@ -99,6 +99,7 @@ static int sdxi_pci_probe(struct pci_dev *pdev,
>  
>  static void sdxi_pci_remove(struct pci_dev *pdev)
>  {
> +	sdxi_unregister(&pdev->dev);
>  	pci_disable_sriov(pdev);
>  }

[Severity: High]
Should pci_disable_sriov(pdev) be called before sdxi_unregister(&pdev->dev)
in sdxi_pci_remove()?

When SR-IOV virtual functions have been enabled via sriov_configure after PF
registration, calling sdxi_unregister() first invokes sdxi_dev_stop() on the
PF while the child VFs are still active and bound to their driver instances:

sdxi_pci_remove()
  sdxi_unregister()
    sdxi_dev_stop()
      sdxi->bus_ops->reset() -> sdxi_pci_reset()
        pci_reset_function_locked()

If the native MMIO stop sequence fails or times out, sdxi_dev_stop() falls
back to sdxi_pci_reset() and issues a PF function-level reset (or clears bus
mastering). A PF FLR clears PCI_SRIOV_CTRL_VFE in hardware and resets all VFs
underneath their bound drivers, and pci_dev_restore() -> sriov_restore_state()
then re-enables PCI_SRIOV_CTRL_VFE with uninitialized post-reset VFs before
pci_disable_sriov(pdev) runs to unbind and remove them.

Calling pci_disable_sriov(pdev) before sdxi_unregister(&pdev->dev) would
ensure all child VFs are unbound, stopped, and disabled before the PF itself
is stopped or reset.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261103-sdxi-base-v4-0-3668ccc7aab8@amd.com?part=11