PCI Hotplug: serialize pci_hp_register and pci_hp_deregister

Convert the pci_hotplug_slot_list_lock, which only protected the
list of hotplug slots, to a pci_hp_mutex which now protects both
interfaces.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
index 1cdeb64..e715248 100644 (file)
--- a/drivers/pci/hotplug/pci_hotplug_core.c
+++ b/drivers/pci/hotplug/pci_hotplug_core.c
@@ -37,6 +37,7 @@
 #include <linux/init.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/pci_hotplug.h>
 #include <asm/uaccess.h>
@@ -61,7 +62,7 @@ static int debug;
 //////////////////////////////////////////////////////////////////
 
 static LIST_HEAD(pci_hotplug_slot_list);
-static DEFINE_SPINLOCK(pci_hotplug_slot_list_lock);
+static DEFINE_MUTEX(pci_hp_mutex);
 
 /* these strings match up with the values in pci_bus_speed */
 static char *pci_bus_speed_strings[] = {
@@ -530,16 +531,12 @@ static struct hotplug_slot *get_slot_from_name (const char *name)
        struct hotplug_slot *slot;
        struct list_head *tmp;
 
-       spin_lock(&pci_hotplug_slot_list_lock);
        list_for_each (tmp, &pci_hotplug_slot_list) {
                slot = list_entry (tmp, struct hotplug_slot, slot_list);
                if (strcmp(slot->name, name) == 0)
-                       goto out;
+                       return slot;
        }
-       slot = NULL;
-out:
-       spin_unlock(&pci_hotplug_slot_list_lock);
-       return slot;
+       return NULL;
 }
 
 /**
@@ -570,9 +567,13 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
                return -EINVAL;
        }
 
+       mutex_lock(&pci_hp_mutex);
+
        /* Check if we have already registered a slot with the same name. */
-       if (get_slot_from_name(name))
-               return -EEXIST;
+       if (get_slot_from_name(name)) {
+               result = -EEXIST;
+               goto out;
+       }
 
        /*
         * No problems if we call this interface from both ACPI_PCI_SLOT
@@ -580,13 +581,15 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
         * pci_slot, the interface will simply bump the refcount.
         */
        pci_slot = pci_create_slot(bus, slot_nr, name, slot);
-       if (IS_ERR(pci_slot))
-               return PTR_ERR(pci_slot);
+       if (IS_ERR(pci_slot)) {
+               result = PTR_ERR(pci_slot);
+               goto cleanup;
+       }
 
        if (pci_slot->hotplug) {
                dbg("%s: already claimed\n", __func__);
-               pci_destroy_slot(pci_slot);
-               return -EBUSY;
+               result = -EBUSY;
+               goto cleanup;
        }
 
        slot->pci_slot = pci_slot;
@@ -597,21 +600,21 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
         */
        if (strcmp(kobject_name(&pci_slot->kobj), name)) {
                result = kobject_rename(&pci_slot->kobj, name);
-               if (result) {
-                       pci_destroy_slot(pci_slot);
-                       return result;
-               }
+               if (result)
+                       goto cleanup;
        }
 
-       spin_lock(&pci_hotplug_slot_list_lock);
        list_add(&slot->slot_list, &pci_hotplug_slot_list);
-       spin_unlock(&pci_hotplug_slot_list_lock);
 
        result = fs_add_slot(pci_slot);
        kobject_uevent(&pci_slot->kobj, KOBJ_ADD);
        dbg("Added slot %s to the list\n", name);
-
+out:
+       mutex_unlock(&pci_hp_mutex);
        return result;
+cleanup:
+       pci_destroy_slot(pci_slot);
+       goto out;
 }
 
 /**
@@ -631,13 +634,14 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
        if (!hotplug)
                return -ENODEV;
 
+       mutex_lock(&pci_hp_mutex);
        temp = get_slot_from_name(hotplug->name);
-       if (temp != hotplug)
+       if (temp != hotplug) {
+               mutex_unlock(&pci_hp_mutex);
                return -ENODEV;
+       }
 
-       spin_lock(&pci_hotplug_slot_list_lock);
        list_del(&hotplug->slot_list);
-       spin_unlock(&pci_hotplug_slot_list_lock);
 
        slot = hotplug->pci_slot;
        fs_remove_slot(slot);
@@ -646,6 +650,7 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
        hotplug->release(hotplug);
        slot->hotplug = NULL;
        pci_destroy_slot(slot);
+       mutex_unlock(&pci_hp_mutex);
 
        return 0;
 }