Re: [RESEND PATCH] PCI: cpci: remove unused fields

Christophe JAILLET
2025-02-13T20:45:52Z

Le 13/02/2025 à 18:39, Guilherme Giacomo Simoes a écrit :
> The `get_power()` and `set_power()` function pointers in the
> `cpci_hp_controller ops` struct were declared but never implemented by
> any driver. To improve code readability and reduce resource usage,
> remove this pointers and replace with a `flags` field.
>
> Use the new `flags` field in `enable_slot()`, `disable_slot()`, and
> `cpci_get_power_s atus()` to track the slot's power state using the
> `SLOT_ENABLED` macro.
>
> Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>
> ---
> drivers/pci/hotplug/cpci_hotplug.h | 3 +--
> drivers/pci/hotplug/cpci_hotplug_core.c | 21 +++++++--------------
> 2 files changed, 8 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/pci/hotplug/cpci_hotplug.h b/drivers/pci/hotplug/cpci_hotplug.h
> index 03fa39ab0c88..c5cb12cad2b4 100644
> --- a/drivers/pci/hotplug/cpci_hotplug.h
> +++ b/drivers/pci/hotplug/cpci_hotplug.h
> @@ -44,8 +44,7 @@ struct cpci_hp_controller_ops {
> int (*enable_irq)(void);
> int (*disable_irq)(void);
> int (*check_irq)(void *dev_id);
> - u8 (*get_power)(struct slot *slot);
> - int (*set_power)(struct slot *slot, int value);
> + int flags;
> };
>
> struct cpci_hp_controller {
> diff --git a/drivers/pci/hotplug/cpci_hotplug_core.c b/drivers/pci/hotplug/cpci_hotplug_core.c
> index d0559d2faf50..87a743c2a5f1 100644
> --- a/drivers/pci/hotplug/cpci_hotplug_core.c
> +++ b/drivers/pci/hotplug/cpci_hotplug_core.c
> @@ -27,6 +27,8 @@
> #define DRIVER_AUTHOR "Scott Murray <scottm@somanetworks.com>"
> #define DRIVER_DESC "CompactPCI Hot Plug Core"
>
> +#define SLOT_ENABLED 0x00000001
> +
> #define MY_NAME "cpci_hotplug"
>
> #define dbg(format, arg...) \
> @@ -71,13 +73,12 @@ static int
> enable_slot(struct hotplug_slot *hotplug_slot)
> {
> struct slot *slot = to_slot(hotplug_slot);
> - int retval = 0;
>
> dbg("%s - physical_slot = %s", __func__, slot_name(slot));
>
> - if (controller->ops->set_power)
> - retval = controller->ops->set_power(slot, 1);
> - return retval;
> + controller->ops->flags |= SLOT_ENABLED;
> +
> + return 0;
> }
>
> static int
> @@ -109,11 +110,7 @@ disable_slot(struct hotplug_slot *hotplug_slot)
> }
> cpci_led_on(slot);
>
> - if (controller->ops->set_power) {
> - retval = controller->ops->set_power(slot, 0);
> - if (retval)
> - goto disable_error;
> - }
> + controller->ops->flags &= ~SLOT_ENABLED;
>
> slot->adapter_status = 0;
>
> @@ -129,11 +126,7 @@ disable_slot(struct hotplug_slot *hotplug_slot)
> static u8
> cpci_get_power_status(struct slot *slot)
> {
> - u8 power = 1;
> -
> - if (controller->ops->get_power)
> - power = controller->ops->get_power(slot);
> - return power;
> + return controller->ops->flags & SLOT_ENABLED;

If neither get_power nor set_power where defined in any driver, then
cpci_get_power_status() was always returning 1.

IIUC, now it may return 1 or 0 depending of if enable_slot() or
disable_slot() have been called.

I don't know the impact of this change and I dont know if it is correct,
but I think you should explain why this change of behavior is fine.

Just my 2c.

CJ

> }
>
> static int