1 files changed, 113 insertions, 28 deletions

diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index 0e009c3ba5f..b6ee352ae45 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -78,6 +78,77 @@ static struct kobj_type pci_slot_ktype = {
 	.default_attrs = pci_slot_default_attrs,
 };
 
+static char *make_slot_name(const char *name)
+{
+	char *new_name;
+	int len, max, dup;
+
+	new_name = kstrdup(name, GFP_KERNEL);
+	if (!new_name)
+		return NULL;
+
+	/*
+	 * Make sure we hit the realloc case the first time through the
+	 * loop.  'len' will be strlen(name) + 3 at that point which is
+	 * enough space for "name-X" and the trailing NUL.
+	 */
+	len = strlen(name) + 2;
+	max = 1;
+	dup = 1;
+
+	for (;;) {
+		struct kobject *dup_slot;
+		dup_slot = kset_find_obj(pci_slots_kset, new_name);
+		if (!dup_slot)
+			break;
+		kobject_put(dup_slot);
+		if (dup == max) {
+			len++;
+			max *= 10;
+			kfree(new_name);
+			new_name = kmalloc(len, GFP_KERNEL);
+			if (!new_name)
+				break;
+		}
+		sprintf(new_name, "%s-%d", name, dup++);
+	}
+
+	return new_name;
+}
+
+static int rename_slot(struct pci_slot *slot, const char *name)
+{
+	int result = 0;
+	char *slot_name;
+
+	if (strcmp(kobject_name(&slot->kobj), name) == 0)
+		return result;
+
+	slot_name = make_slot_name(name);
+	if (!slot_name)
+		return -ENOMEM;
+
+	result = kobject_rename(&slot->kobj, slot_name);
+	kfree(slot_name);
+
+	return result;
+}
+
+static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
+{
+	struct pci_slot *slot;
+	/*
+	 * We already hold pci_bus_sem so don't worry
+	 */
+	list_for_each_entry(slot, &parent->slots, list)
+		if (slot->number == slot_nr) {
+			kobject_get(&slot->kobj);
+			return slot;
+		}
+
+	return NULL;
+}
+
 /**
  * pci_create_slot - create or increment refcount for physical PCI slot
  * @parent: struct pci_bus of parent bridge
@@ -90,7 +161,17 @@ static struct kobj_type pci_slot_ktype = {
  * either return a new &struct pci_slot to the caller, or if the pci_slot
  * already exists, its refcount will be incremented.
  *
- * Slots are uniquely identified by a @pci_bus, @slot_nr, @name tuple.
+ * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
+ *
+ * There are known platforms with broken firmware that assign the same
+ * name to multiple slots. Workaround these broken platforms by renaming
+ * the slots on behalf of the caller. If firmware assigns name N to
+ * multiple slots:
+ *
+ * The first slot is assigned N
+ * The second slot is assigned N-1
+ * The third slot is assigned N-2
+ * etc.
  *
  * Placeholder slots:
  * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
@@ -99,62 +180,67 @@ static struct kobj_type pci_slot_ktype = {
  * the slot. In this scenario, the caller may pass -1 for @slot_nr.
  *
  * The following semantics are imposed when the caller passes @slot_nr ==
- * -1. First, the check for existing %struct pci_slot is skipped, as the
- * caller may know about several unpopulated slots on a given %struct
- * pci_bus, and each slot would have a @slot_nr of -1.  Uniqueness for
- * these slots is then determined by the @name parameter. We expect
- * kobject_init_and_add() to warn us if the caller attempts to create
- * multiple slots with the same name. The other change in semantics is
+ * -1. First, we no longer check for an existing %struct pci_slot, as there
+ * may be many slots with @slot_nr of -1.  The other change in semantics is
  * user-visible, which is the 'address' parameter presented in sysfs will
  * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
  * %struct pci_bus and bb is the bus number. In other words, the devfn of
  * the 'placeholder' slot will not be displayed.
  */
-
 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 				 const char *name,
 				 struct hotplug_slot *hotplug)
 {
 	struct pci_dev *dev;
 	struct pci_slot *slot;
-	int err;
+	int err = 0;
+	char *slot_name = NULL;
 
 	down_write(&pci_bus_sem);
 
 	if (slot_nr == -1)
 		goto placeholder;
 
-	/* If we've already created this slot, bump refcount and return. */
-	list_for_each_entry(slot, &parent->slots, list) {
-		if (slot->number == slot_nr) {
-			kobject_get(&slot->kobj);
-			pr_debug("%s: inc refcount to %d on %04x:%02x:%02x\n",
-				 __func__,
-				 atomic_read(&slot->kobj.kref.refcount),
-				 pci_domain_nr(parent), parent->number,
-				 slot_nr);
-			goto out;
+	/*
+	 * Hotplug drivers are allowed to rename an existing slot,
+	 * but only if not already claimed.
+	 */
+	slot = get_slot(parent, slot_nr);
+	if (slot) {
+		if (hotplug) {
+			if ((err = slot->hotplug ? -EBUSY : 0)
+			     || (err = rename_slot(slot, name))) {
+				kobject_put(&slot->kobj);
+				slot = NULL;
+				goto err;
+			}
 		}
+		goto out;
 	}
 
 placeholder:
 	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
 	if (!slot) {
-		slot = ERR_PTR(-ENOMEM);
-		goto out;
+		err = -ENOMEM;
+		goto err;
 	}
 
 	slot->bus = parent;
 	slot->number = slot_nr;
 
 	slot->kobj.kset = pci_slots_kset;
-	err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
-				   "%s", name);
-	if (err) {
-		printk(KERN_ERR "Unable to register kobject %s\n", name);
+
+	slot_name = make_slot_name(name);
+	if (!slot_name) {
+		err = -ENOMEM;
 		goto err;
 	}
 
+	err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
+				   "%s", slot_name);
+	if (err)
+		goto err;
+
 	INIT_LIST_HEAD(&slot->list);
 	list_add(&slot->list, &parent->slots);
 
@@ -166,10 +252,10 @@ placeholder:
 	pr_debug("%s: created pci_slot on %04x:%02x:%02x\n",
 		 __func__, pci_domain_nr(parent), parent->number, slot_nr);
 
- out:
+out:
 	up_write(&pci_bus_sem);
 	return slot;
- err:
+err:
 	kfree(slot);
 	slot = ERR_PTR(err);
 	goto out;
@@ -210,7 +296,6 @@ EXPORT_SYMBOL_GPL(pci_renumber_slot);
  * just call kobject_put on its kobj and let our release methods do the
  * rest.
  */
-
 void pci_destroy_slot(struct pci_slot *slot)
 {
 	pr_debug("%s: dec refcount to %d on %04x:%02x:%02x\n", __func__,