From: "David E. Box" <[email protected]> The VMD driver calls pci_enabled_link_state as a callback from pci_bus_walk. Both will acquire the pci_bus_sem lock leading to a lockdep warning. Add an argument to pci_enable_link_state to set whether the lock should be acquired. In the VMD driver, set the argument to false since the lock will already be obtained by pci_bus_walk.
Still, review comments needs to be addressed. However, this fix is helping to unblock CI execution for now. References: https://gitlab.freedesktop.org/drm/intel/-/issues/8316 Reported-by: Ville Syrjälä <[email protected]> Fixes: de82f60f9c86 ("PCI/ASPM: Add pci_enable_link_state()") Link: https://lore.kernel.org/linux-pci/zbjko%[email protected]/ Signed-off-by: David E. Box <[email protected]> Signed-off-by: Swati Sharma <[email protected]> --- drivers/pci/controller/vmd.c | 2 +- drivers/pci/pcie/aspm.c | 9 ++++++--- include/linux/pci.h | 5 +++-- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 990630ec57c6..45aa35744eae 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -737,7 +737,7 @@ static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata) if (!(features & VMD_FEAT_BIOS_PM_QUIRK)) return 0; - pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL); + pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL, false); pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR); if (!pos) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 66d7514ca111..5b5a600bb864 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -1147,8 +1147,9 @@ EXPORT_SYMBOL(pci_disable_link_state); * * @pdev: PCI device * @state: Mask of ASPM link states to enable + * @sem: Boolean to acquire/release pci_bus_sem */ -int pci_enable_link_state(struct pci_dev *pdev, int state) +int pci_enable_link_state(struct pci_dev *pdev, int state, bool sem) { struct pcie_link_state *link = pcie_aspm_get_link(pdev); @@ -1165,7 +1166,8 @@ int pci_enable_link_state(struct pci_dev *pdev, int state) return -EPERM; } - down_read(&pci_bus_sem); + if (sem) + down_read(&pci_bus_sem); mutex_lock(&aspm_lock); link->aspm_default = 0; if (state & PCIE_LINK_STATE_L0S) @@ -1186,7 +1188,8 @@ int pci_enable_link_state(struct pci_dev *pdev, int state) link->clkpm_default = (state & PCIE_LINK_STATE_CLKPM) ? 1 : 0; pcie_set_clkpm(link, policy_to_clkpm_state(link)); mutex_unlock(&aspm_lock); - up_read(&pci_bus_sem); + if (sem) + up_read(&pci_bus_sem); return 0; } diff --git a/include/linux/pci.h b/include/linux/pci.h index b50e5c79f7e3..1fe4557e87b9 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1708,7 +1708,7 @@ extern bool pcie_ports_native; #ifdef CONFIG_PCIEASPM int pci_disable_link_state(struct pci_dev *pdev, int state); int pci_disable_link_state_locked(struct pci_dev *pdev, int state); -int pci_enable_link_state(struct pci_dev *pdev, int state); +int pci_enable_link_state(struct pci_dev *pdev, int state, bool sem); void pcie_no_aspm(void); bool pcie_aspm_support_enabled(void); bool pcie_aspm_enabled(struct pci_dev *pdev); @@ -1717,7 +1717,8 @@ static inline int pci_disable_link_state(struct pci_dev *pdev, int state) { return 0; } static inline int pci_disable_link_state_locked(struct pci_dev *pdev, int state) { return 0; } -static inline int pci_enable_link_state(struct pci_dev *pdev, int state) +static inline int +pci_enable_link_state(struct pci_dev *pdev, int state, bool sem) { return 0; } static inline void pcie_no_aspm(void) { } static inline bool pcie_aspm_support_enabled(void) { return false; } -- 2.25.1
