[+cc Alex, Krzysztof]
On Wed, Nov 11, 2020 at 06:22:03PM +0800, Yicong Yang wrote:
> Previosly we use pci_probe_reset_function() to probe whehter a function
> can be reset and use __pci_reset_function_locked() to perform a function
> reset. These two functions have lots of common lines.
s/Previosly/Previously/
s/we use/we used/
s/whehter/whether/
I'm not a big fan of dual-purpose functions that decide whether to
probe or to reset based on a parameter. Those two things just don't
seem semantically compatible. But I do see your point about common
lines, and the underlying functions (pci_dev_specific_reset(),
pci_af_flr(), etc) already have that structure.
Let me think about this some more.
> Factor the two functions and reduce the redundancy.
>
> Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
> ---
> drivers/pci/pci.c | 61 ++++++++++++++++-------------------------------------
> drivers/pci/pci.h | 2 +-
> drivers/pci/probe.c | 2 +-
> 3 files changed, 20 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index e39c549..e3e5f0f 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5006,9 +5006,11 @@ static void pci_dev_restore(struct pci_dev *dev)
> }
>
> /**
> - * __pci_reset_function_locked - reset a PCI device function while holding
> - * the @dev mutex lock.
> + * pci_probe_reset_function - check whether the device can be safely reset
> + * or reset a PCI device function while holding
> + * the @dev mutex lock.
> * @dev: PCI device to reset
> + * @probe: Probe or not whether the device can be reset.
> *
> * Some devices allow an individual function to be reset without affecting
> * other functions in the same device. The PCI device must be responsive
> @@ -5022,10 +5024,10 @@ static void pci_dev_restore(struct pci_dev *dev)
> * device including MSI, bus mastering, BARs, decoding IO and memory spaces,
> * etc.
> *
> - * Returns 0 if the device function was successfully reset or negative if the
> - * device doesn't support resetting a single function.
> + * Returns 0 if the device function can be reset or was successfully reset.
> + * negative if the device doesn't support resetting a single function.
> */
> -int __pci_reset_function_locked(struct pci_dev *dev)
> +int pci_probe_reset_function(struct pci_dev *dev, int probe)
> {
> int rc;
>
> @@ -5039,61 +5041,34 @@ int __pci_reset_function_locked(struct pci_dev *dev)
> * other error, we're also finished: this indicates that further
> * reset mechanisms might be broken on the device.
> */
> - rc = pci_dev_specific_reset(dev, 0);
> + rc = pci_dev_specific_reset(dev, probe);
> if (rc != -ENOTTY)
> return rc;
> if (pcie_has_flr(dev)) {
> + if (probe)
> + return 0;
> rc = pcie_flr(dev);
> if (rc != -ENOTTY)
> return rc;
> }
> - rc = pci_af_flr(dev, 0);
> + rc = pci_af_flr(dev, probe);
> if (rc != -ENOTTY)
> return rc;
> - rc = pci_pm_reset(dev, 0);
> + rc = pci_pm_reset(dev, probe);
> if (rc != -ENOTTY)
> return rc;
> - rc = pci_dev_reset_slot_function(dev, 0);
> + rc = pci_dev_reset_slot_function(dev, probe);
> if (rc != -ENOTTY)
> return rc;
> - return pci_parent_bus_reset(dev, 0);
> +
> + return pci_parent_bus_reset(dev, probe);
> }
> -EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
>
> -/**
> - * pci_probe_reset_function - check whether the device can be safely reset
> - * @dev: PCI device to reset
> - *
> - * Some devices allow an individual function to be reset without affecting
> - * other functions in the same device. The PCI device must be responsive
> - * to PCI config space in order to use this function.
> - *
> - * Returns 0 if the device function can be reset or negative if the
> - * device doesn't support resetting a single function.
> - */
> -int pci_probe_reset_function(struct pci_dev *dev)
> +int __pci_reset_function_locked(struct pci_dev *dev)
> {
> - int rc;
> -
> - might_sleep();
> -
> - rc = pci_dev_specific_reset(dev, 1);
> - if (rc != -ENOTTY)
> - return rc;
> - if (pcie_has_flr(dev))
> - return 0;
> - rc = pci_af_flr(dev, 1);
> - if (rc != -ENOTTY)
> - return rc;
> - rc = pci_pm_reset(dev, 1);
> - if (rc != -ENOTTY)
> - return rc;
> - rc = pci_dev_reset_slot_function(dev, 1);
> - if (rc != -ENOTTY)
> - return rc;
> -
> - return pci_parent_bus_reset(dev, 1);
> + return pci_probe_reset_function(dev, 0);
> }
> +EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
>
> /**
> * pci_reset_function - quiesce and reset a PCI device function
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index fa12f7c..73740dd 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -39,7 +39,7 @@ enum pci_mmap_api {
> int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai,
> enum pci_mmap_api mmap_api);
>
> -int pci_probe_reset_function(struct pci_dev *dev);
> +int pci_probe_reset_function(struct pci_dev *dev, int probe);
> int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
> int pci_bus_error_reset(struct pci_dev *dev);
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 03d3712..793cc8a 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2403,7 +2403,7 @@ static void pci_init_capabilities(struct pci_dev *dev)
>
> pcie_report_downtraining(dev);
>
> - if (pci_probe_reset_function(dev) == 0)
> + if (pci_probe_reset_function(dev, 1) == 0)
> dev->reset_fn = 1;
> }
>
> --
> 2.8.1
>
