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
