powerpc/eeh: Global mutex to protect PE tree
authorGavin Shan <shangw@linux.vnet.ibm.com>
Tue, 11 Sep 2012 19:16:18 +0000 (19:16 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Tue, 18 Sep 2012 05:32:33 +0000 (15:32 +1000)
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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/platforms/pseries/eeh_pe.c

index 30b8d96ed54dc2a82d3eb0da8de72bbfe9905c78..9d35543736ed103dcbb1f7cd48883a646cd947fc 100644 (file)
@@ -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;
 }