From b37e8e4b8520f7b7b32fbf11d8428cf3dfc1ecb5 Mon Sep 17 00:00:00 2001
From: "David E. Box" <david.e.box@linux.intel.com>
Date: Thu, 30 Mar 2023 17:41:35 +0530
Subject: [PATCH] PCI/ASPM: pci_enable_link_state: Add argument to acquire bus
lock
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The VMD driver calls pci_enabled_link_state as a callback from
pci_bus_walk. Both will acquire the pci_bus_sem lock leading to a lockdep
warning. Add an argument to pci_enable_link_state to set whether the lock
should be acquired. In the VMD driver, set the argument to false since the
lock will already be obtained by pci_bus_walk.
Still, review comments needs to be addressed. However, this fix
is helping to unblock CI execution for now.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/8316
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Fixes: de82f60f9c86 ("PCI/ASPM: Add pci_enable_link_state()")
Link: https://lore.kernel.org/linux-pci/ZBjko%2FifunIwsK2v@intel.com/
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230330121135.15414-1-swati2.sharma@intel.com
---
drivers/pci/controller/vmd.c | 2 +-
drivers/pci/pcie/aspm.c | 9 ++++++---
include/linux/pci.h | 5 +++--
3 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 94ba61fe1c44..5d2485b91695 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -751,7 +751,7 @@ static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata)
if (!(features & VMD_FEAT_BIOS_PM_QUIRK))
return 0;
- pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL);
+ pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL, false);
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
if (!pos)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 50b04ae5c394..c08e3dfa2af1 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1118,8 +1118,9 @@ EXPORT_SYMBOL(pci_disable_link_state);
*
* @pdev: PCI device
* @state: Mask of ASPM link states to enable
+ * @sem: Boolean to acquire/release pci_bus_sem
*/
-int pci_enable_link_state(struct pci_dev *pdev, int state)
+int pci_enable_link_state(struct pci_dev *pdev, int state, bool sem)
{
struct pcie_link_state *link = pcie_aspm_get_link(pdev);
@@ -1136,7 +1137,8 @@ int pci_enable_link_state(struct pci_dev *pdev, int state)
return -EPERM;
}
- down_read(&pci_bus_sem);
+ if (sem)
+ down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
link->aspm_default = 0;
if (state & PCIE_LINK_STATE_L0S)
@@ -1157,7 +1159,8 @@ int pci_enable_link_state(struct pci_dev *pdev, int state)
link->clkpm_default = (state & PCIE_LINK_STATE_CLKPM) ? 1 : 0;
pcie_set_clkpm(link, policy_to_clkpm_state(link));
mutex_unlock(&aspm_lock);
- up_read(&pci_bus_sem);
+ if (sem)
+ up_read(&pci_bus_sem);
return 0;
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 60ca768bc867..ab9e1e6bd7b1 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1828,7 +1828,7 @@ extern bool pcie_ports_native;
#ifdef CONFIG_PCIEASPM
int pci_disable_link_state(struct pci_dev *pdev, int state);
int pci_disable_link_state_locked(struct pci_dev *pdev, int state);
-int pci_enable_link_state(struct pci_dev *pdev, int state);
+int pci_enable_link_state(struct pci_dev *pdev, int state, bool sem);
void pcie_no_aspm(void);
bool pcie_aspm_support_enabled(void);
bool pcie_aspm_enabled(struct pci_dev *pdev);
@@ -1837,7 +1837,8 @@ static inline int pci_disable_link_state(struct pci_dev *pdev, int state)
{ return 0; }
static inline int pci_disable_link_state_locked(struct pci_dev *pdev, int state)
{ return 0; }
-static inline int pci_enable_link_state(struct pci_dev *pdev, int state)
+static inline int
+pci_enable_link_state(struct pci_dev *pdev, int state, bool sem)
{ return 0; }
static inline void pcie_no_aspm(void) { }
static inline bool pcie_aspm_support_enabled(void) { return false; }
--
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