Re: [PATCH] Bluetooth: btmtk: Fix btmtk.c undefined reference build error

[Luiz Augusto von Dentz]

Hi Chris,

On Wed, Jul 10, 2024 at 3:38 AM Chris Lu <chris.lu@xxxxxxxxxxxx> wrote:
>
> MediaTek move some usb interface related function to btmtk.c which
> may cause build failed if BT USB Kconfig wasn't enabled.
> Fix undefined reference by adding config check.
>
> Fixes: 39a9e1c69e74 Bluetooth: btmtk: move btusb_mtk_hci_wmt_sync to btmtk.c
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202407091928.AH0aGZnx-lkp@xxxxxxxxx/
> Signed-off-by: Chris Lu <chris.lu@xxxxxxxxxxxx>
> ---
>  drivers/bluetooth/btmtk.c | 2 ++
>  drivers/bluetooth/btmtk.h | 4 ++++
>  2 files changed, 6 insertions(+)
>
> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> index b7c348687a77..9789296ad4f6 100644
> --- a/drivers/bluetooth/btmtk.c
> +++ b/drivers/bluetooth/btmtk.c
> @@ -437,6 +437,7 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb)
>  }
>  EXPORT_SYMBOL_GPL(btmtk_process_coredump);
>
> +#if IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK)
>  static void btmtk_usb_wmt_recv(struct urb *urb)
>  {
>         struct hci_dev *hdev = urb->context;
> @@ -1487,6 +1488,7 @@ int btmtk_usb_shutdown(struct hci_dev *hdev)
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(btmtk_usb_shutdown);
> +#endif
>
>  MODULE_AUTHOR("Sean Wang <sean.wang@xxxxxxxxxxxx>");
>  MODULE_AUTHOR("Mark Chen <mark-yw.chen@xxxxxxxxxxxx>");
> diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
> index 453ed5131a37..890dbe9beff8 100644
> --- a/drivers/bluetooth/btmtk.h
> +++ b/drivers/bluetooth/btmtk.h
> @@ -165,6 +165,7 @@ struct btmtk_data {
>         btmtk_reset_sync_func_t reset_sync;
>         struct btmtk_coredump_info cd_info;
>
> +#if IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK)
>         struct usb_device *udev;
>         struct usb_interface *intf;
>         struct usb_anchor *ctrl_anchor;
> @@ -177,6 +178,7 @@ struct btmtk_data {
>
>         /* spinlock for ISO data transmission */
>         spinlock_t isorxlock;
> +#endif

If I recall this correctly it is not a good practice to use #if inside
structs as it would change its overall size, memory layout, etc, and
it also makes it difficult to use if (IS_DEFINED) and let the compiler
eliminate dead code instead of using the preprocessor like you doing.

>  };
>
>  typedef int (*wmt_cmd_sync_func_t)(struct hci_dev *,
> @@ -202,6 +204,7 @@ int btmtk_process_coredump(struct hci_dev *hdev, struct sk_buff *skb);
>  void btmtk_fw_get_filename(char *buf, size_t size, u32 dev_id, u32 fw_ver,
>                            u32 fw_flavor);
>
> +#if IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK)
>  int btmtk_usb_subsys_reset(struct hci_dev *hdev, u32 dev_id);
>
>  int btmtk_usb_recv_acl(struct hci_dev *hdev, struct sk_buff *skb);
> @@ -216,6 +219,7 @@ int btmtk_usb_suspend(struct hci_dev *hdev);
>  int btmtk_usb_setup(struct hci_dev *hdev);
>
>  int btmtk_usb_shutdown(struct hci_dev *hdev);
> +#endif
>  #else
>
>  static inline int btmtk_set_bdaddr(struct hci_dev *hdev,
> --
> 2.18.0
>


-- 
Luiz Augusto von Dentz