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>

1 files changed, 28 insertions, 23 deletions

diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
index 1cdeb642fdcf..e71524825180 100644
--- 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;
 }