Re: [PATCH 1/2] pciehp: Rename duplicate slot name N as N-1, N-2, N-M...

[Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>]

Tested-by & Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

Thnaks,
Kenji Kaneshige



Alex Chiang wrote:
> Commit 3800345f723fd130d50434d4717b99d4a9f383c8 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 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.
> 
> Signed-off-by: Alex Chiang <achiang@hp.com>
> ---
>  drivers/pci/hotplug/pciehp.h      |    1 -
>  drivers/pci/hotplug/pciehp_core.c |   21 ++++++++++++++-------
>  drivers/pci/hotplug/pciehp_hpc.c  |   11 +----------
>  3 files changed, 15 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
> index e3a1e7e..9e6cec6 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 3677495..4fd5355 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 ad27e9e..ab31f5b 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);