[PATCH 3/3] ppc/eeh: global mutex to protect PE tree

[Gavin Shan <shangw@linux.vnet.ibm.com>]

We have missed lots of situations where the PE hierarchy tree need
protection through the EEH global mutex. The patch fixes that for
those public APIs implemented in eeh_pe.c. The only exception is
eeh_pe_restore_bars() because it calls eeh_pe_dev_traverse(), which
has been protected by the mutex.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/eeh_pe.c |   39 +++++++++++++++++++++++++-----
 1 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/eeh_pe.c b/arch/powerpc/platforms/pseries/eeh_pe.c
index a2646cf..07b6e4b 100644
--- a/arch/powerpc/platforms/pseries/eeh_pe.c
+++ b/arch/powerpc/platforms/pseries/eeh_pe.c
@@ -99,8 +99,6 @@ static struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb)
 {
 	struct eeh_pe *pe;
 
-	eeh_lock();
-
 	list_for_each_entry(pe, &eeh_phb_pe, child) {
 		/*
 		 * Actually, we needn't check the type since
@@ -114,8 +112,6 @@ static struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb)
 		}
 	}
 
-	eeh_unlock();
-
 	return NULL;
 }
 
@@ -192,14 +188,21 @@ void *eeh_pe_dev_traverse(struct eeh_pe *root,
 		return NULL;
 	}
 
+	eeh_lock();
+
 	/* Traverse root PE */
 	for (pe = root; pe; pe = eeh_pe_next(pe, root)) {
 		eeh_pe_for_each_dev(pe, edev) {
 			ret = fn(edev, flag);
-			if (ret) return ret;
+			if (ret) {
+				eeh_unlock();
+				return ret;
+			}
 		}
 	}
 
+	eeh_unlock();
+
 	return NULL;
 }
 
@@ -251,9 +254,7 @@ static struct eeh_pe *eeh_pe_get(struct eeh_dev *edev)
 	struct eeh_pe *root = eeh_phb_pe_get(edev->phb);
 	struct eeh_pe *pe;
 
-	eeh_lock();
 	pe = eeh_pe_traverse(root, __eeh_pe_get, edev);
-	eeh_unlock();
 
 	return pe;
 }
@@ -307,6 +308,8 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 {
 	struct eeh_pe *pe, *parent;
 
+	eeh_lock();
+
 	/*
 	 * Search the PE has been existing or not according
 	 * to the PE address. If that has been existing, the
@@ -316,6 +319,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	pe = eeh_pe_get(edev);
 	if (pe && !(pe->type & EEH_PE_INVALID)) {
 		if (!edev->pe_config_addr) {
+			eeh_unlock();
 			pr_err("%s: PE with addr 0x%x already exists\n",
 				__func__, edev->config_addr);
 			return -EEXIST;
@@ -327,6 +331,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 
 		/* Put the edev to PE */
 		list_add_tail(&edev->list, &pe->edevs);
+		eeh_unlock();
 		pr_debug("EEH: Add %s to Bus PE#%x\n",
 			edev->dn->full_name, pe->addr);
 
@@ -345,6 +350,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 			parent->type &= ~EEH_PE_INVALID;
 			parent = parent->parent;
 		}
+		eeh_unlock();
 		pr_debug("EEH: Add %s to Device PE#%x, Parent PE#%x\n",
 			edev->dn->full_name, pe->addr, pe->parent->addr);
 
@@ -354,6 +360,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	/* Create a new EEH PE */
 	pe = eeh_pe_alloc(edev->phb, EEH_PE_DEVICE);
 	if (!pe) {
+		eeh_unlock();
 		pr_err("%s: out of memory!\n", __func__);
 		return -ENOMEM;
 	}
@@ -370,6 +377,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	if (!parent) {
 		parent = eeh_phb_pe_get(edev->phb);
 		if (!parent) {
+			eeh_unlock();
 			pr_err("%s: No PHB PE is found (PHB Domain=%d)\n",
 				__func__, edev->phb->global_number);
 			edev->pe = NULL;
@@ -386,6 +394,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 	list_add_tail(&pe->child, &parent->child_list);
 	list_add_tail(&edev->list, &pe->edevs);
 	edev->pe = pe;
+	eeh_unlock();
 	pr_debug("EEH: Add %s to Device PE#%x, Parent PE#%x\n",
 		edev->dn->full_name, pe->addr, pe->parent->addr);
 
@@ -413,6 +422,8 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev, int purge_pe)
 		return -EEXIST;
 	}
 
+	eeh_lock();
+
 	/* Remove the EEH device */
 	pe = edev->pe;
 	edev->pe = NULL;
@@ -457,6 +468,8 @@ int eeh_rmv_from_parent_pe(struct eeh_dev *edev, int purge_pe)
 		pe = parent;
 	}
 
+	eeh_unlock();
+
 	return 0;
 }
 
@@ -502,7 +515,9 @@ static void *__eeh_pe_state_mark(void *data, void *flag)
  */
 void eeh_pe_state_mark(struct eeh_pe *pe, int state)
 {
+	eeh_lock();
 	eeh_pe_traverse(pe, __eeh_pe_state_mark, &state);
+	eeh_unlock();
 }
 
 /**
@@ -536,7 +551,9 @@ static void *__eeh_pe_state_clear(void *data, void *flag)
  */
 void eeh_pe_state_clear(struct eeh_pe *pe, int state)
 {
+	eeh_lock();
 	eeh_pe_traverse(pe, __eeh_pe_state_clear, &state);
+	eeh_unlock();
 }
 
 /**
@@ -598,6 +615,10 @@ static void *eeh_restore_one_device_bars(void *data, void *flag)
  */
 void eeh_pe_restore_bars(struct eeh_pe *pe)
 {
+	/*
+	 * We needn't take the EEH lock since eeh_pe_dev_traverse()
+	 * will take that.
+	 */
 	eeh_pe_dev_traverse(pe, eeh_restore_one_device_bars, NULL);
 }
 
@@ -617,6 +638,8 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 	struct eeh_dev *edev;
 	struct pci_dev *pdev;
 
+	eeh_lock();
+
 	if (pe->type & EEH_PE_PHB) {
 		bus = pe->phb->bus;
 	} else if (pe->type & EEH_PE_BUS) {
@@ -626,5 +649,7 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 			bus = pdev->bus;
 	}
 
+	eeh_unlock();
+
 	return bus;
 }
-- 
1.7.5.4