This is a note to let you know that I've just added the patch titled PCI: let pci_disable_link_state propagate errors to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pci-let-pci_disable_link_state-propagate-errors.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 568b1487084809a7257e371ca4ede0b79eb55794 Author: Heiner Kallweit <hkallweit1@xxxxxxxxx> Date: Tue Jun 18 23:13:48 2019 +0200 PCI: let pci_disable_link_state propagate errors [ Upstream commit 4cfd218855923a07dc02a5bec3d3bb37a118ebc2 ] Drivers may rely on pci_disable_link_state() having disabled certain ASPM link states. If OS can't control ASPM then pci_disable_link_state() turns into a no-op w/o informing the caller. The driver therefore may falsely assume the respective ASPM link states are disabled. Let pci_disable_link_state() propagate errors to the caller, enabling the caller to react accordingly. Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Stable-dep-of: 3cb4f534bac0 ("Revert "PCI/ASPM: Disable only ASPM_STATE_L1 when driver, disables L1"") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 118c91586798d..f2b5f3a8535e5 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -1078,18 +1078,18 @@ void pcie_aspm_powersave_config_link(struct pci_dev *pdev) up_read(&pci_bus_sem); } -static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem) +static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem) { struct pci_dev *parent = pdev->bus->self; struct pcie_link_state *link; if (!pci_is_pcie(pdev)) - return; + return 0; if (pdev->has_secondary_link) parent = pdev; if (!parent || !parent->link_state) - return; + return -EINVAL; /* * A driver requested that ASPM be disabled on this device, but @@ -1101,7 +1101,7 @@ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem) */ if (aspm_disabled) { pci_warn(pdev, "can't disable ASPM; OS doesn't have ASPM control\n"); - return; + return -EPERM; } if (sem) @@ -1120,11 +1120,13 @@ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem) mutex_unlock(&aspm_lock); if (sem) up_read(&pci_bus_sem); + + return 0; } -void pci_disable_link_state_locked(struct pci_dev *pdev, int state) +int pci_disable_link_state_locked(struct pci_dev *pdev, int state) { - __pci_disable_link_state(pdev, state, false); + return __pci_disable_link_state(pdev, state, false); } EXPORT_SYMBOL(pci_disable_link_state_locked); @@ -1132,14 +1134,14 @@ EXPORT_SYMBOL(pci_disable_link_state_locked); * pci_disable_link_state - Disable device's link state, so the link will * never enter specific states. Note that if the BIOS didn't grant ASPM * control to the OS, this does nothing because we can't touch the LNKCTL - * register. + * register. Returns 0 or a negative errno. * * @pdev: PCI device * @state: ASPM link state to disable */ -void pci_disable_link_state(struct pci_dev *pdev, int state) +int pci_disable_link_state(struct pci_dev *pdev, int state) { - __pci_disable_link_state(pdev, state, true); + return __pci_disable_link_state(pdev, state, true); } EXPORT_SYMBOL(pci_disable_link_state); diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h index df28af5cef210..67064145d76e0 100644 --- a/include/linux/pci-aspm.h +++ b/include/linux/pci-aspm.h @@ -24,11 +24,12 @@ #define PCIE_LINK_STATE_CLKPM 4 #ifdef CONFIG_PCIEASPM -void pci_disable_link_state(struct pci_dev *pdev, int state); -void pci_disable_link_state_locked(struct pci_dev *pdev, int state); +int pci_disable_link_state(struct pci_dev *pdev, int state); +int pci_disable_link_state_locked(struct pci_dev *pdev, int state); void pcie_no_aspm(void); #else -static inline void pci_disable_link_state(struct pci_dev *pdev, int state) { } +static inline int pci_disable_link_state(struct pci_dev *pdev, int state) +{ return 0; } static inline void pcie_no_aspm(void) { } #endif