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__,