| Message ID | 604f2954-c60c-d2aa-3849-9a2f8872001c@gmail.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Commit | 4cfd218855923a07dc02a5bec3d3bb37a118ebc2 |
| Headers | show |
| Series | PCI: let pci_disable_link_state propagate errors | expand |
On Tue, Jun 18, 2019 at 11:13:48PM +0200, Heiner Kallweit wrote: > 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> Thanks, I think this makes good sense. > --- > drivers/pci/pcie/aspm.c | 20 +++++++++++--------- > include/linux/pci-aspm.h | 7 ++++--- > 2 files changed, 15 insertions(+), 12 deletions(-) > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index fd4cb7508..e44af7f4d 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); > > diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h > index df28af5ce..67064145d 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 > > -- > 2.22.0 > >
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index fd4cb7508..e44af7f4d 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); diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h index df28af5ce..67064145d 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
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> --- drivers/pci/pcie/aspm.c | 20 +++++++++++--------- include/linux/pci-aspm.h | 7 ++++--- 2 files changed, 15 insertions(+), 12 deletions(-)