PCI: pciehp: Rename duplicate slot name N as N-1, N-2, N-M...

Commit 3800345f723fd130d50434d4717b99d4a9f383c8 (pciehp: fix slot name)
introduces the pciehp_slot_with_bus module parameter, which was intended
to help work around broken firmware that assigns the same name to multiple
slots.

Commit 9e4f2e8d4ddb04ad16a3828cd9a369a5a5287009 (pciehp: add message about
pciehp_slot_with_bus option) tells the user to use the above parameter
in the event of a name collision.

This approach is sub-optimal because it requires too much work from
the user.

Instead, let's rename the slot on behalf of the user. If firmware
assigns the name N to multiple slots, then:

	The first registered slot is assigned N
	The second registered slot is assigned N-1
	The third registered slot is assigned N-2
	The Mth registered slot becomes N-M

In the event we overflow the slot->name parameter, we report an
error to the user.

This is a temporary fix until the entire PCI core can be reworked
such that individual drivers no longer have to manage their own
slot names.

Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 15 insertions, 18 deletions

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index e3a1e7e7dba2..9e6cec67e1cc 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -43,7 +43,6 @@ extern int pciehp_poll_mode;
 extern int pciehp_poll_time;
 extern int pciehp_debug;
 extern int pciehp_force;
-extern int pciehp_slot_with_bus;
 extern struct workqueue_struct *pciehp_wq;
 
 #define dbg(format, arg...)                                             \
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 3677495c4f91..4fd5355bc3b5 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -41,7 +41,6 @@ int pciehp_debug;
 int pciehp_poll_mode;
 int pciehp_poll_time;
 int pciehp_force;
-int pciehp_slot_with_bus;
 struct workqueue_struct *pciehp_wq;
 
 #define DRIVER_VERSION  "0.4"
@@ -56,12 +55,10 @@ module_param(pciehp_debug, bool, 0644);
 module_param(pciehp_poll_mode, bool, 0644);
 module_param(pciehp_poll_time, int, 0644);
 module_param(pciehp_force, bool, 0644);
-module_param(pciehp_slot_with_bus, bool, 0644);
 MODULE_PARM_DESC(pciehp_debug, "Debugging mode enabled or not");
 MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not");
 MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds");
 MODULE_PARM_DESC(pciehp_force, "Force pciehp, even if _OSC and OSHP are missing");
-MODULE_PARM_DESC(pciehp_slot_with_bus, "Use bus number in the slot name");
 
 #define PCIE_MODULE_NAME "pciehp"
 
@@ -194,6 +191,7 @@ static int init_slots(struct controller *ctrl)
         struct slot *slot;
         struct hotplug_slot *hotplug_slot;
         struct hotplug_slot_info *info;
+        int len, dup = 1;
         int retval = -ENOMEM;
 
         list_for_each_entry(slot, &ctrl->slot_list, slot_list) {
@@ -220,15 +218,24 @@ static int init_slots(struct controller *ctrl)
                 dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x "
                     "slot_device_offset=%x\n", slot->bus, slot->device,
                     slot->hp_slot, slot->number, ctrl->slot_device_offset);
+duplicate_name:
                 retval = pci_hp_register(hotplug_slot,
                                          ctrl->pci_dev->subordinate,
                                          slot->device);
                 if (retval) {
+                        /*
+                         * If slot N already exists, we'll try to create
+                         * slot N-1, N-2 ... N-M, until we overflow.
+                         */
+                        if (retval == -EEXIST) {
+                                len = snprintf(slot->name, SLOT_NAME_SIZE,
+                                               "%d-%d", slot->number, dup++);
+                                if (len < SLOT_NAME_SIZE)
+                                        goto duplicate_name;
+                                else
+                                        err("duplicate slot name overflow\n");
+                        }
                         err("pci_hp_register failed with error %d\n", retval);
-                        if (retval == -EEXIST)
-                                err("Failed to register slot because of name "
-                                    "collision. Try \'pciehp_slot_with_bus\' "
-                                    "module option.\n");
                         goto error_info;
                 }
                 /* create additional sysfs entries */
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index ad27e9e225a6..ab31f5ba665d 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -1030,15 +1030,6 @@ static void pcie_shutdown_notification(struct controller *ctrl)
         pciehp_free_irq(ctrl);
 }
 
-static void make_slot_name(struct slot *slot)
-{
-        if (pciehp_slot_with_bus)
-                snprintf(slot->name, SLOT_NAME_SIZE, "%04d_%04d",
-                         slot->bus, slot->number);
-        else
-                snprintf(slot->name, SLOT_NAME_SIZE, "%d", slot->number);
-}
-
 static int pcie_init_slot(struct controller *ctrl)
 {
         struct slot *slot;
@@ -1053,7 +1044,7 @@ static int pcie_init_slot(struct controller *ctrl)
         slot->device = ctrl->slot_device_offset + slot->hp_slot;
         slot->hpc_ops = ctrl->hpc_ops;
         slot->number = ctrl->first_slot;
-        make_slot_name(slot);
+        snprintf(slot->name, SLOT_NAME_SIZE, "%d", slot->number);
         mutex_init(&slot->lock);
         INIT_DELAYED_WORK(&slot->work, pciehp_queue_pushbutton_work);
         list_add(&slot->slot_list, &ctrl->slot_list);