Re: [PATCH] drm/xe/pf: Take pci_rescan_remove_lock mutex when disabling VFs

["Piotr Piórkowski" <piotr.piorkowski@intel.com>]

Michal Wajdeczko <michal.wajdeczko@intel.com> wrote on pią [2026-lut-27 22:40:47 +0100]:
> Since recent commit a5338e365c45 ("PCI/IOV: Fix race between SR-IOV
> enable/disable and hotplug") the driver pci_driver.sriov_configure
> hook is called with the mutex pci_rescan_remove_lock already taken.
> 
> As we are using this hook as-is during driver removal, we get:
> 
>  [ ] xe 0000:4d:00.0: [drm:xe_pci_sriov_configure [xe]] PF: disabling 1 VF
>  [ ] ------------[ cut here ]------------
>  [ ] debug_locks && !(lock_is_held(&(&pci_rescan_remove_lock)->dep_map) != 0)
>  [ ] WARNING: drivers/pci/remove.c:130 at pci_stop_and_remove_bus_device+0x4c/0x50, CPU#32: rmmod/6476
>  [ ] RIP: 0010:pci_stop_and_remove_bus_device+0x4c/0x50
>  [ ] Call Trace:
>  [ ]  <TASK>
>  [ ]  pci_iov_remove_virtfn+0xd1/0x140
>  [ ]  sriov_disable+0x42/0x100
>  [ ]  pci_disable_sriov+0x34/0x50
>  [ ]  xe_pci_sriov_configure+0x2d0/0x1150 [xe]
>  [ ]  xe_pci_remove+0x7c/0x190 [xe]
>  [ ]  pci_device_remove+0x41/0xb0
>  [ ]  device_remove+0x43/0x80
>  [ ]  device_release_driver_internal+0x215/0x280
>  [ ]  driver_detach+0x50/0xb0
>  [ ]  bus_remove_driver+0x86/0x120
>  [ ]  driver_unregister+0x2f/0x60
>  [ ]  pci_unregister_driver+0x22/0xc0
>  [ ]  xe_unregister_pci_driver+0x15/0x20 [xe]
>  [ ]  xe_exit+0x1f/0x34 [xe]
> 
> Fix that by taking a pci_rescan_remove_lock as it is now expected.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_pci.c       |  2 +-
>  drivers/gpu/drm/xe/xe_pci_sriov.c | 20 ++++++++++++++++++++
>  2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 3ac99472d6dd..fb0abd768e67 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -1010,7 +1010,7 @@ static void xe_pci_remove(struct pci_dev *pdev)
>  	struct xe_device *xe = pdev_to_xe_device(pdev);
>  
>  	if (IS_SRIOV_PF(xe))
> -		xe_pci_sriov_configure(pdev, 0);
> +		xe_pci_sriov_disable_vfs(pdev);
>  
>  	if (xe_survivability_mode_is_boot_enabled(xe))
>  		return;
> diff --git a/drivers/gpu/drm/xe/xe_pci_sriov.c b/drivers/gpu/drm/xe/xe_pci_sriov.c
> index 3fd22034f03e..2a3fd3578ef2 100644
> --- a/drivers/gpu/drm/xe/xe_pci_sriov.c
> +++ b/drivers/gpu/drm/xe/xe_pci_sriov.c
> @@ -239,6 +239,26 @@ int xe_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
>  		return pf_disable_vfs(xe);
>  }
>  
> +/**
> + * xe_pci_sriov_disable_vfs() - Disable all VFs.
> + * @pdev: the PF's &pci_dev
> + *
> + * This is a simple wrapper around our function that implements the
> + * pci_driver.sriov_configure hook but also takes a required mutex.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
> +int xe_pci_sriov_disable_vfs(struct pci_dev *pdev)
> +{
> +	int ret;
> +
> +	pci_lock_rescan_remove();
> +	ret = xe_pci_sriov_configure(pdev, 0);
> +	pci_unlock_rescan_remove();
> +
> +	return ret;
> +}
> +
LGTM:
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>


>  /**
>   * xe_pci_sriov_get_vf_pdev() - Lookup the VF's PCI device using the VF identifier.
>   * @pdev: the PF's &pci_dev
> -- 
> 2.47.1
> 

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