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authorHeiner Kallweit <hkallweit1@gmail.com>2019-06-18 23:13:48 +0200
committerDavid S. Miller <davem@davemloft.net>2019-06-21 22:05:42 -0400
commit4cfd218855923a07dc02a5bec3d3bb37a118ebc2 (patch)
tree9a58ea195f240a1bba5a5e33baf8d0d4fe8adfbb
parentdca73a65a68329ee386d3ff473152bac66eaab39 (diff)
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>
-rw-r--r--drivers/pci/pcie/aspm.c20
-rw-r--r--include/linux/pci-aspm.h7
2 files changed, 15 insertions, 12 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);
diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h
index df28af5cef21..67064145d76e 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