On 5/24/24 6:19 PM, Dan Williams wrote:
> Alex reports a new vfio-pci lockdep warning resulting from the
> cfg_access_lock lock_map added recently.
>
> Add the missing annotation to pci_cfg_access_trylock() and adjust the
> lock_map acquisition to be symmetrical relative to pci_lock.
>
> Fixes: 7e89efc6e9e4 ("PCI: Lock upstream bridge for pci_reset_function()")
> Reported-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Closes: http://lore.kernel.org/r/20240523131005.5578e3de.alex.williamson@xxxxxxxxxx
> Tested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> ---
> drivers/pci/access.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> index 30f031de9cfe..3595130ff719 100644
> --- a/drivers/pci/access.c
> +++ b/drivers/pci/access.c
> @@ -289,11 +289,10 @@ void pci_cfg_access_lock(struct pci_dev *dev)
> {
> might_sleep();
>
> - lock_map_acquire(&dev->cfg_access_lock);
> -
> raw_spin_lock_irq(&pci_lock);
> if (dev->block_cfg_access)
> pci_wait_cfg(dev);
> + lock_map_acquire(&dev->cfg_access_lock);
> dev->block_cfg_access = 1;
> raw_spin_unlock_irq(&pci_lock);
> }
> @@ -315,8 +314,10 @@ bool pci_cfg_access_trylock(struct pci_dev *dev)
> raw_spin_lock_irqsave(&pci_lock, flags);
> if (dev->block_cfg_access)
> locked = false;
> - else
> + else {
> + lock_map_acquire(&dev->cfg_access_lock);
> dev->block_cfg_access = 1;
> + }
> raw_spin_unlock_irqrestore(&pci_lock, flags);
>
> return locked;
> @@ -342,11 +343,10 @@ void pci_cfg_access_unlock(struct pci_dev *dev)
> WARN_ON(!dev->block_cfg_access);
>
> dev->block_cfg_access = 0;
> + lock_map_release(&dev->cfg_access_lock);
> raw_spin_unlock_irqrestore(&pci_lock, flags);
>
> wake_up_all(&pci_cfg_wait);
> -
> - lock_map_release(&dev->cfg_access_lock);
> }
> EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);
>
>
