Merge tag 'pci-v6.7-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci

Pull pci fixes from Bjorn Helgaas:

 - Limit Max_Read_Request_Size (MRRS) on some MIPS Loongson systems
   because they don't all support MRRS > 256, and firmware doesn't
   always initialize it correctly, which meant some PCIe devices didn't
   work (Jiaxun Yang)

 - Add and use pci_enable_link_state_locked() to prevent potential
   deadlocks in vmd and qcom drivers (Johan Hovold)

 - Revert recent (v6.5) acpiphp resource assignment changes that fixed
   issues with hot-adding devices on a root bus or with large BARs, but
   introduced new issues with GPU initialization and hot-adding SCSI
   disks in QEMU VMs and (Bjorn Helgaas)

* tag 'pci-v6.7-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci:
  Revert "PCI: acpiphp: Reassign resources on bridge if necessary"
  PCI/ASPM: Add pci_disable_link_state_locked() lockdep assert
  PCI/ASPM: Clean up __pci_disable_link_state() 'sem' parameter
  PCI: qcom: Clean up ASPM comment
  PCI: qcom: Fix potential deadlock when enabling ASPM
  PCI: vmd: Fix potential deadlock when enabling ASPM
  PCI/ASPM: Add pci_enable_link_state_locked()
  PCI: loongson: Limit MRRS to 256

drivers/pci/controller/dwc/pcie-qcom.c

@@ -968,9 +968,12 @@ static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
 
 static int qcom_pcie_enable_aspm(struct pci_dev *pdev, void *userdata)
 {
-	/* Downstream devices need to be in D0 state before enabling PCI PM substates */
+	/*
+	 * Downstream devices need to be in D0 state before enabling PCI PM
+	 * substates.
+	 */
 	pci_set_power_state(pdev, PCI_D0);
-	pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL);
+	pci_enable_link_state_locked(pdev, PCIE_LINK_STATE_ALL);
 
 	return 0;
 }

drivers/pci/controller/pci-loongson.c

@@ -80,13 +80,49 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 			DEV_LS7A_LPC, system_bus_quirk);
 
+/*
+ * Some Loongson PCIe ports have hardware limitations on their Maximum Read
+ * Request Size. They can't handle anything larger than this.  Sane
+ * firmware will set proper MRRS at boot, so we only need no_inc_mrrs for
+ * bridges. However, some MIPS Loongson firmware doesn't set MRRS properly,
+ * so we have to enforce maximum safe MRRS, which is 256 bytes.
+ */
+#ifdef CONFIG_MIPS
+static void loongson_set_min_mrrs_quirk(struct pci_dev *pdev)
+{
+	struct pci_bus *bus = pdev->bus;
+	struct pci_dev *bridge;
+	static const struct pci_device_id bridge_devids[] = {
+		{ PCI_VDEVICE(LOONGSON, DEV_LS2K_PCIE_PORT0) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT0) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT1) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT2) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT3) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT4) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT5) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT6) },
+		{ 0, },
+	};
+
+	/* look for the matching bridge */
+	while (!pci_is_root_bus(bus)) {
+		bridge = bus->self;
+		bus = bus->parent;
+
+		if (pci_match_id(bridge_devids, bridge)) {
+			if (pcie_get_readrq(pdev) > 256) {
+				pci_info(pdev, "limiting MRRS to 256\n");
+				pcie_set_readrq(pdev, 256);
+			}
+			break;
+		}
+	}
+}
+DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_set_min_mrrs_quirk);
+#endif
+
 static void loongson_mrrs_quirk(struct pci_dev *pdev)
 {
-	/*
-	 * Some Loongson PCIe ports have h/w limitations of maximum read
-	 * request size. They can't handle anything larger than this. So
-	 * force this limit on any devices attached under these ports.
-	 */
 	struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);
 
 	bridge->no_inc_mrrs = 1;

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_locked(pdev, PCIE_LINK_STATE_ALL);
 
 	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
 	if (!pos)

drivers/pci/hotplug/acpiphp_glue.c

@@ -512,15 +512,12 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
 				if (pass && dev->subordinate) {
 					check_hotplug_bridge(slot, dev);
 					pcibios_resource_survey_bus(dev->subordinate);
-					if (pci_is_root_bus(bus))
-						__pci_bus_size_bridges(dev->subordinate, &add_list);
+					__pci_bus_size_bridges(dev->subordinate,
+							       &add_list);
 				}
 			}
 		}
-		if (pci_is_root_bus(bus))
-			__pci_bus_assign_resources(bus, &add_list, NULL);
-		else
-			pci_assign_unassigned_bridge_resources(bus->self);
+		__pci_bus_assign_resources(bus, &add_list, NULL);
 	}
 
 	acpiphp_sanitize_bus(bus);

drivers/pci/pcie/aspm.c

@@ -1041,7 +1041,7 @@ static struct pcie_link_state *pcie_aspm_get_link(struct pci_dev *pdev)
 	return bridge->link_state;
 }
 
-static int __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 locked)
 {
 	struct pcie_link_state *link = pcie_aspm_get_link(pdev);
 
@@ -1060,7 +1060,7 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
 		return -EPERM;
 	}
 
-	if (sem)
+	if (!locked)
 		down_read(&pci_bus_sem);
 	mutex_lock(&aspm_lock);
 	if (state & PCIE_LINK_STATE_L0S)
@@ -1082,7 +1082,7 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
 		link->clkpm_disable = 1;
 	pcie_set_clkpm(link, policy_to_clkpm_state(link));
 	mutex_unlock(&aspm_lock);
-	if (sem)
+	if (!locked)
 		up_read(&pci_bus_sem);
 
 	return 0;
@@ -1090,7 +1090,9 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
 
 int pci_disable_link_state_locked(struct pci_dev *pdev, int state)
 {
-	return __pci_disable_link_state(pdev, state, false);
+	lockdep_assert_held_read(&pci_bus_sem);
+
+	return __pci_disable_link_state(pdev, state, true);
 }
 EXPORT_SYMBOL(pci_disable_link_state_locked);
 
@@ -1105,21 +1107,11 @@ EXPORT_SYMBOL(pci_disable_link_state_locked);
  */
 int pci_disable_link_state(struct pci_dev *pdev, int state)
 {
-	return __pci_disable_link_state(pdev, state, true);
+	return __pci_disable_link_state(pdev, state, false);
 }
 EXPORT_SYMBOL(pci_disable_link_state);
 
-/**
- * pci_enable_link_state - Clear and set the default device link state so that
- * the link may be allowed to enter the specified 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. Also note that this does not enable states
- * disabled by pci_disable_link_state(). Return 0 or a negative errno.
- *
- * @pdev: PCI device
- * @state: Mask of ASPM link states to enable
- */
-int pci_enable_link_state(struct pci_dev *pdev, int state)
+static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked)
 {
 	struct pcie_link_state *link = pcie_aspm_get_link(pdev);
 
@@ -1136,7 +1128,8 @@ int pci_enable_link_state(struct pci_dev *pdev, int state)
 		return -EPERM;
 	}
 
-	down_read(&pci_bus_sem);
+	if (!locked)
+		down_read(&pci_bus_sem);
 	mutex_lock(&aspm_lock);
 	link->aspm_default = 0;
 	if (state & PCIE_LINK_STATE_L0S)
@@ -1157,12 +1150,48 @@ 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 (!locked)
+		up_read(&pci_bus_sem);
 
 	return 0;
 }
+
+/**
+ * pci_enable_link_state - Clear and set the default device link state so that
+ * the link may be allowed to enter the specified 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. Also note that this does not enable states
+ * disabled by pci_disable_link_state(). Return 0 or a negative errno.
+ *
+ * @pdev: PCI device
+ * @state: Mask of ASPM link states to enable
+ */
+int pci_enable_link_state(struct pci_dev *pdev, int state)
+{
+	return __pci_enable_link_state(pdev, state, false);
+}
 EXPORT_SYMBOL(pci_enable_link_state);
 
+/**
+ * pci_enable_link_state_locked - Clear and set the default device link state
+ * so that the link may be allowed to enter the specified 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. Also note that this does not enable states
+ * disabled by pci_disable_link_state(). Return 0 or a negative errno.
+ *
+ * @pdev: PCI device
+ * @state: Mask of ASPM link states to enable
+ *
+ * Context: Caller holds pci_bus_sem read lock.
+ */
+int pci_enable_link_state_locked(struct pci_dev *pdev, int state)
+{
+	lockdep_assert_held_read(&pci_bus_sem);
+
+	return __pci_enable_link_state(pdev, state, true);
+}
+EXPORT_SYMBOL(pci_enable_link_state_locked);
+
 static int pcie_aspm_set_policy(const char *val,
 				const struct kernel_param *kp)
 {

include/linux/pci.h

@@ -1829,6 +1829,7 @@ extern bool pcie_ports_native;
 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_locked(struct pci_dev *pdev, int state);
 void pcie_no_aspm(void);
 bool pcie_aspm_support_enabled(void);
 bool pcie_aspm_enabled(struct pci_dev *pdev);
@@ -1839,6 +1840,8 @@ 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)
 { return 0; }
+static inline int pci_enable_link_state_locked(struct pci_dev *pdev, int state)
+{ return 0; }
 static inline void pcie_no_aspm(void) { }
 static inline bool pcie_aspm_support_enabled(void) { return false; }
 static inline bool pcie_aspm_enabled(struct pci_dev *pdev) { return false; }