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path: root/drivers/pci/slot.c
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Diffstat (limited to 'drivers/pci/slot.c')
-rw-r--r--drivers/pci/slot.c141
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__,