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| author |   Heiner Kallweit <hkallweit1@gmail.com> | 2019-06-18 23:13:48 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2019-06-21 22:05:42 -0400 |
| commit | 4cfd218855923a07dc02a5bec3d3bb37a118ebc2 (patch) | |
| tree | 9a58ea195f240a1bba5a5e33baf8d0d4fe8adfbb /drivers | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next (diff) | |
| download | linux-dev-4cfd218855923a07dc02a5bec3d3bb37a118ebc2.tar.xz linux-dev-4cfd218855923a07dc02a5bec3d3bb37a118ebc2.zip | |
PCI: let pci_disable_link_state propagate errors
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@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index fd4cb75088f9..e44af7f4d37f 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -1062,18 +1062,18 @@ 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 @@ -1085,7 +1085,7 @@ 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) @@ -1105,11 +1105,13 @@ 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); @@ -1117,14 +1119,14 @@ 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); |