Re: [PATCH] staging: comedi: das08: Reduce conditional compilation

Randy Dunlap
2012-06-08T20:20:46Z

On 06/08/2012 11:38 AM, Ian Abbott wrote:

> This code is used by some combination of the CONFIG_COMEDI_DAS08_CS,
> CONFIG_COMEDI_DAS08_ISA, and CONFIG_COMEDI_DAS08_PCI and contains a lot
> of conditional compilation.
>
> Remove most of the conditional compilation, relying on the compiler to
> optimize out unused static functions and data. Use the '__maybe_unused'
> tag for those functions that cause compiler warnings as a result of
> this.
>
> Also change the DO_COMEDI_DRIVER_REGISTER macro from a conditionally
> defined macro to a manifest constant macro to allow it to be tested
> outside the preprocessor (although this is not currently needed).
>
> Signed-off-by: Ian Abbott <abbotti@mev.co.uk>

Acked-by: Randy Dunlap <rdunlap@xenotime.net>

Thanks.

> ---
> v2: Add test to top of das08_attach_pci() to allow compiler to optimize
> most of it out if CONFIG_COMEDI_DAS08_PCI is not enabled.
> ---
> drivers/staging/comedi/drivers/das08.c | 74 +++++++++++++-------------------
> 1 files changed, 30 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/das08.c b/drivers/staging/comedi/drivers/das08.c
> index fa2784d..f99f72b 100644
> --- a/drivers/staging/comedi/drivers/das08.c
> +++ b/drivers/staging/comedi/drivers/das08.c
> @@ -60,9 +60,9 @@
>
> #define DRV_NAME "das08"
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_ISA) || IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> -#define DO_COMEDI_DRIVER_REGISTER
> -#endif
> +#define DO_COMEDI_DRIVER_REGISTER \
> + (IS_ENABLED(CONFIG_COMEDI_DAS08_ISA) || \
> + IS_ENABLED(CONFIG_COMEDI_DAS08_PCI))
>
> #define PCI_VENDOR_ID_COMPUTERBOARDS 0x1307
> #define PCI_DEVICE_ID_PCIDAS08 0x29
> @@ -341,22 +341,19 @@ static int das08_do_wbits(struct comedi_device *dev, struct comedi_subdevice *s,
> return 2;
> }
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_ISA)
> -static int das08jr_di_rbits(struct comedi_device *dev,
> - struct comedi_subdevice *s,
> - struct comedi_insn *insn, unsigned int *data)
> +static int __maybe_unused
> +das08jr_di_rbits(struct comedi_device *dev, struct comedi_subdevice *s,
> + struct comedi_insn *insn, unsigned int *data)
> {
> data[0] = 0;
> data[1] = inb(dev->iobase + DAS08JR_DIO);
>
> return 2;
> }
> -#endif
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_ISA)
> -static int das08jr_do_wbits(struct comedi_device *dev,
> - struct comedi_subdevice *s,
> - struct comedi_insn *insn, unsigned int *data)
> +static int __maybe_unused
> +das08jr_do_wbits(struct comedi_device *dev, struct comedi_subdevice *s,
> + struct comedi_insn *insn, unsigned int *data)
> {
> struct das08_private_struct *devpriv = dev->private;
>
> @@ -370,12 +367,10 @@ static int das08jr_do_wbits(struct comedi_device *dev,
>
> return 2;
> }
> -#endif
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_ISA)
> -static int das08jr_ao_winsn(struct comedi_device *dev,
> - struct comedi_subdevice *s,
> - struct comedi_insn *insn, unsigned int *data)
> +static int __maybe_unused
> +das08jr_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
> + struct comedi_insn *insn, unsigned int *data)
> {
> int n;
> int lsb, msb;
> @@ -401,7 +396,6 @@ static int das08jr_ao_winsn(struct comedi_device *dev,
>
> return n;
> }
> -#endif
>
> /*
> *
> @@ -409,10 +403,9 @@ static int das08jr_ao_winsn(struct comedi_device *dev,
> * a different method to force an update.
> *
> */
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_ISA)
> -static int das08ao_ao_winsn(struct comedi_device *dev,
> - struct comedi_subdevice *s,
> - struct comedi_insn *insn, unsigned int *data)
> +static int __maybe_unused
> +das08ao_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
> + struct comedi_insn *insn, unsigned int *data)
> {
> int n;
> int lsb, msb;
> @@ -438,7 +431,6 @@ static int das08ao_ao_winsn(struct comedi_device *dev,
>
> return n;
> }
> -#endif
>
> static unsigned int i8254_read_channel_low(unsigned int base, int chan)
> {
> @@ -570,7 +562,7 @@ static int das08_counter_config(struct comedi_device *dev,
> return 2;
> }
>
> -#ifdef DO_COMEDI_DRIVER_REGISTER
> +#if DO_COMEDI_DRIVER_REGISTER
> static const struct das08_board_struct das08_boards[] = {
> #if IS_ENABLED(CONFIG_COMEDI_DAS08_ISA)
> {
> @@ -943,7 +935,6 @@ int das08_common_attach(struct comedi_device *dev, unsigned long iobase)
> }
> EXPORT_SYMBOL_GPL(das08_common_attach);
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> static int das08_pci_attach_common(struct comedi_device *dev,
> struct pci_dev *pdev)
> {
> @@ -951,6 +942,9 @@ static int das08_pci_attach_common(struct comedi_device *dev,
> unsigned long pci_iobase;
> struct das08_private_struct *devpriv = dev->private;
>
> + if (!IS_ENABLED(CONFIG_COMEDI_DAS08_PCI))
> + return -EINVAL;
> +
> devpriv->pdev = pdev;
> /* enable PCI device and reserve I/O spaces */
> if (comedi_pci_enable(pdev, dev->driver->driver_name)) {
> @@ -977,28 +971,28 @@ static int das08_pci_attach_common(struct comedi_device *dev,
> #endif
> return das08_common_attach(dev, iobase);
> }
> -#endif
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> static const struct das08_board_struct *
> das08_find_pci_board(struct pci_dev *pdev)
> {
> +#if DO_COMEDI_DRIVER_REGISTER
> unsigned int i;
> for (i = 0; i < ARRAY_SIZE(das08_boards); i++)
> if (das08_boards[i].bustype == pci &&
> pdev->device == das08_boards[i].id)
> return &das08_boards[i];
> +#endif
> return NULL;
> }
> -#endif
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> /* only called in the PCI probe path, via comedi_pci_auto_config() */
> -static int __devinit das08_attach_pci(struct comedi_device *dev,
> - struct pci_dev *pdev)
> +static int __devinit __maybe_unused
> +das08_attach_pci(struct comedi_device *dev, struct pci_dev *pdev)
> {
> int ret;
>
> + if (!IS_ENABLED(CONFIG_COMEDI_DAS08_PCI))
> + return -EINVAL;
> ret = alloc_private(dev, sizeof(struct das08_private_struct));
> if (ret < 0)
> return ret;
> @@ -1010,9 +1004,7 @@ static int __devinit das08_attach_pci(struct comedi_device *dev,
> }
> return das08_pci_attach_common(dev, pdev);
> }
> -#endif
>
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> static struct pci_dev *das08_find_pci(struct comedi_device *dev,
> int bus, int slot)
> {
> @@ -1063,10 +1055,9 @@ static struct pci_dev *das08_find_pci(struct comedi_device *dev,
> thisboard->name);
> return NULL;
> }
> -#endif
>
> -#ifdef DO_COMEDI_DRIVER_REGISTER
> -static int das08_attach(struct comedi_device *dev, struct comedi_devconfig *it)
> +static int __maybe_unused
> +das08_attach(struct comedi_device *dev, struct comedi_devconfig *it)
> {
> const struct das08_board_struct *thisboard = comedi_board(dev);
> struct das08_private_struct *devpriv;
> @@ -1097,7 +1088,6 @@ static int das08_attach(struct comedi_device *dev, struct comedi_devconfig *it)
> } else
> return -EIO;
> }
> -#endif /* DO_COMEDI_DRIVER_REGISTER */
>
> void das08_common_detach(struct comedi_device *dev)
> {
> @@ -1106,8 +1096,7 @@ void das08_common_detach(struct comedi_device *dev)
> }
> EXPORT_SYMBOL_GPL(das08_common_detach);
>
> -#ifdef DO_COMEDI_DRIVER_REGISTER
> -static void das08_detach(struct comedi_device *dev)
> +static void __maybe_unused das08_detach(struct comedi_device *dev)
> {
> const struct das08_board_struct *thisboard = comedi_board(dev);
> struct das08_private_struct *devpriv = dev->private;
> @@ -1126,16 +1115,13 @@ static void das08_detach(struct comedi_device *dev)
> }
> }
> }
> -#endif /* DO_COMEDI_DRIVER_REGISTER */
>
> -#ifdef DO_COMEDI_DRIVER_REGISTER
> +#if DO_COMEDI_DRIVER_REGISTER
> static struct comedi_driver das08_driver = {
> .driver_name = DRV_NAME,
> .module = THIS_MODULE,
> .attach = das08_attach,
> -#if IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> .attach_pci = das08_attach_pci,
> -#endif
> .detach = das08_detach,
> .board_name = &das08_boards[0].name,
> .num_names = sizeof(das08_boards) / sizeof(struct das08_board_struct),
> @@ -1170,7 +1156,7 @@ static struct pci_driver das08_pci_driver = {
> };
> #endif /* CONFIG_COMEDI_DAS08_PCI */
>
> -#ifdef DO_COMEDI_DRIVER_REGISTER
> +#if DO_COMEDI_DRIVER_REGISTER
> #if IS_ENABLED(CONFIG_COMEDI_DAS08_PCI)
> module_comedi_pci_driver(das08_driver, das08_pci_driver);
> #else

--
~Randy