Re: [PATCH v2] x86/pmc_atom: Fix warning when CONFIG_DEBUG_FS=n

Ingo Molnar
2014-09-17T12:24:33Z

* Martin Kelly <martin@martingkelly.com> wrote:

> When compiling with CONFIG_DEBUG_FS=n, gcc emits an unused variable
> warning for pmc_atom.c because "ret" is used only within the
> CONFIG_DEBUG_FS block. This patch adds a dummy #ifdef for
> pmc_dbgfs_register when CONFIG_DEBUG_FS=n to simplify the code and
> remove the warning.
>
> Signed-off-by: Martin Kelly <martkell@amazon.com>
> ---
> Changes in v2:
> - Implemented Ingo Molnar's suggestion to #ifdef the function rather
> than the lines.
> ---
> arch/x86/kernel/pmc_atom.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/pmc_atom.c b/arch/x86/kernel/pmc_atom.c
> index 0c424a6..d06527a 100644
> --- a/arch/x86/kernel/pmc_atom.c
> +++ b/arch/x86/kernel/pmc_atom.c
> @@ -235,6 +235,11 @@ err:
> pmc_dbgfs_unregister(pmc);
> return -ENODEV;
> }
> +#else
> +static int pmc_dbgfs_register(struct pmc_dev *pmc, struct pci_dev *pdev)
> +{
> + return 0;
> +}
> #endif /* CONFIG_DEBUG_FS */

Ok, that part is good.

>
> static int pmc_setup_dev(struct pci_dev *pdev)
> @@ -262,13 +267,11 @@ static int pmc_setup_dev(struct pci_dev *pdev)
> /* PMC hardware registers setup */
> pmc_hw_reg_setup(pmc);
>
> -#ifdef CONFIG_DEBUG_FS
> ret = pmc_dbgfs_register(pmc, pdev);
> if (ret) {
> iounmap(pmc->regmap);
> return ret;
> }
> -#endif /* CONFIG_DEBUG_FS */
> return 0;
> }

Just to paint the bike shed a bit, this could be further
simplified to something like:

...

ret = pmc_dbgfs_register(pmc, pdev);
if (ret)
iounmap(pmc->regmap);

return ret;

and then your patch will be perfect! :-)

Thanks,

Ingo