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SubjectRe: [PATCH v5 04/16] PCI: prevent duplicate slot names
commit 2338f56b789bb030434be828c4788679d72901b5
Author: Alex Chiang <>
Date: Thu Oct 9 19:56:58 2008 -0600

PCI: update pci_create_slot() to take a 'hotplug' param

Slot detection drivers can co-exist with hotplug drivers. The names
of the detected/claimed slots may be different depending on module
load order.

For legacy reasons, we need to allow hotplug drivers to override
the slot name if a detection driver is loaded first (and they find
the same slots).

Creating and overriding slot names should be an atomic operation,
otherwise you get a locking nightmare as various drivers race to
call pci_create_slot().

pci_create_slot() is already serialized by grabbing the pci_bus_sem.

We update the API and add a 'hotplug' param, which is:

set if the caller is a hotplug driver
unset if the caller is a detection driver

pci_create_slot() does not actually use the 'hotplug' parameter in this
patch. A later patch will add the logic that uses it.

Signed-off-by: Alex Chiang <>

diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
index d5b4ef8..8d4a568 100644
--- a/drivers/acpi/pci_slot.c
+++ b/drivers/acpi/pci_slot.c
@@ -150,7 +150,7 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)

snprintf(name, sizeof(name), "%u", (u32)sun);
- pci_slot = pci_create_slot(pci_bus, device, name);
+ pci_slot = pci_create_slot(pci_bus, device, name, NULL);
if (IS_ERR(pci_slot)) {
err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
index 0e7a511..191b58e 100644
--- a/drivers/pci/hotplug/pci_hotplug_core.c
+++ b/drivers/pci/hotplug/pci_hotplug_core.c
@@ -579,7 +579,7 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
* driver and call it here again. If we've already created the
* pci_slot, the interface will simply bump the refcount.
- pci_slot = pci_create_slot(bus, slot_nr, name);
+ pci_slot = pci_create_slot(bus, slot_nr, name, slot);
if (IS_ERR(pci_slot))
return PTR_ERR(pci_slot);

diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index b9b90ab..0e009c3 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -83,6 +83,7 @@ static struct kobj_type pci_slot_ktype = {
* @parent: struct pci_bus of parent bridge
* @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
* @name: user visible string presented in /sys/bus/pci/slots/<name>
+ * @hotplug: set if caller is hotplug driver, NULL otherwise
* PCI slots have first class attributes such as address, speed, width,
* and a &struct pci_slot is used to manage them. This interface will
@@ -111,7 +112,8 @@ static struct kobj_type pci_slot_ktype = {

struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
- const char *name)
+ const char *name,
+ struct hotplug_slot *hotplug)
struct pci_dev *dev;
struct pci_slot *slot;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 5d96b7a..8bbbbbc 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -508,7 +508,8 @@ struct pci_bus *pci_create_bus(struct device *parent, int bus,
struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev,
int busnr);
struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
- const char *name);
+ const char *name,
+ struct hotplug_slot *hotplug);
void pci_destroy_slot(struct pci_slot *slot);
void pci_renumber_slot(struct pci_slot *slot, int slot_nr);
int pci_scan_slot(struct pci_bus *bus, int devfn);

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