From a477b9cd37aa81a490dfa3265b7ff4f2c5a92463 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 1 Aug 2017 20:11:02 -0500 Subject: [PATCH] PCI: Add pci_reset_function_locked() The implementation of PCI workarounds may require that the device is reset from its probe function. This implies that the PCI device lock is already held, and makes calling pci_reset_function() impossible (since it will itself try to take that lock). Add pci_reset_function_locked(), which is the equivalent of pci_reset_function(), except that it requires the PCI device lock to be already held by the caller. Tested-by: Ard Biesheuvel Signed-off-by: Marc Zyngier [bhelgaas: folded in fix for conflict with 52354b9d1f46 ("PCI: Remove __pci_dev_reset() and pci_dev_reset()")] Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # 4.11: 52354b9d1f46: PCI: Remove __pci_dev_reset() and pci_dev_reset() Cc: stable@vger.kernel.org # 4.11 --- drivers/pci/pci.c | 35 +++++++++++++++++++++++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 36 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af0cc3456dc1..b4b7eab29400 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4259,6 +4259,41 @@ int pci_reset_function(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_reset_function); +/** + * pci_reset_function_locked - quiesce and reset a PCI device function + * @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. + * + * This function does not just reset the PCI portion of a device, but + * clears all the state associated with the device. This function differs + * from __pci_reset_function() in that it saves and restores device state + * over the reset. It also differs from pci_reset_function() in that it + * requires the PCI device lock to be held. + * + * Returns 0 if the device function was successfully reset or negative if the + * device doesn't support resetting a single function. + */ +int pci_reset_function_locked(struct pci_dev *dev) +{ + int rc; + + rc = pci_probe_reset_function(dev); + if (rc) + return rc; + + pci_dev_save_and_disable(dev); + + rc = __pci_reset_function_locked(dev); + + pci_dev_restore(dev); + + return rc; +} +EXPORT_SYMBOL_GPL(pci_reset_function_locked); + /** * pci_try_reset_function - quiesce and reset a PCI device function * @dev: PCI device to reset diff --git a/include/linux/pci.h b/include/linux/pci.h index 4869e66dd659..a75c13673852 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1067,6 +1067,7 @@ void pcie_flr(struct pci_dev *dev); int __pci_reset_function(struct pci_dev *dev); int __pci_reset_function_locked(struct pci_dev *dev); int pci_reset_function(struct pci_dev *dev); +int pci_reset_function_locked(struct pci_dev *dev); int pci_try_reset_function(struct pci_dev *dev); int pci_probe_reset_slot(struct pci_slot *slot); int pci_reset_slot(struct pci_slot *slot); -- 2.20.1