Re: [PATCH v2 1/6] mmc: sdhci: Use EXPORT_PM_FN_NS_GPL() for exporting PM functions

[Adrian Hunter <adrian.hunter@intel.com>]

On 9/12/24 18:36, Andy Shevchenko wrote:
> On Mon, Dec 09, 2024 at 12:38:59PM +0200, Adrian Hunter wrote:
>> On 1/11/24 12:11, Andy Shevchenko wrote:
>>> Switch from ugly ifdeffery to using EXPORT_PM_FN_NS_GPL()
>>> for exporting PM functions. This helps cleaning up the other
>>> SDHCI drivers in the future.
>>
>> It seems sdhci is the first code in the kernel to use
>> EXPORT_PM_FN_NS_GPL() but it was not asked for ;-)
>>
>> As such, can you fill in a little background.  I am not
>> sure what it achieves.  Why have CONFIG_PM if not to
>> #ifdef dependent code behind it?
> 
> It makes sure that the code elimination happens at compile time and

Does it eliminate the code?  Maybe I am missing something,
but it looks like it is still there:

$ grep CONFIG_PM .config
# CONFIG_PM is not set
# CONFIG_PMIC_OPREGION is not set
# CONFIG_PMBUS is not set
# CONFIG_PMIC_ADP5520 is not set
# CONFIG_PMIC_DA903X is not set
CONFIG_PM_DEVFREQ=y
# CONFIG_PM_DEVFREQ_EVENT is not set
CONFIG_PM_OPP=y
$ objdump -d drivers/mmc/host/sdhci.ko | grep sdhci_suspend_host
00000000000089f0 <__pfx_sdhci_suspend_host>:
0000000000008a00 <sdhci_suspend_host>:
    8a16:       e8 00 00 00 00          call   8a1b <sdhci_suspend_host+0x1b>
    8a29:       74 0c                   je     8a37 <sdhci_suspend_host+0x37>
    8a35:       75 54                   jne    8a8b <sdhci_suspend_host+0x8b>
    8a4c:       0f 85 06 01 00 00       jne    8b58 <sdhci_suspend_host+0x158>
    8a66:       0f 85 00 01 00 00       jne    8b6c <sdhci_suspend_host+0x16c>
    8a7b:       e8 00 00 00 00          call   8a80 <sdhci_suspend_host+0x80>
    8a86:       e9 00 00 00 00          jmp    8a8b <sdhci_suspend_host+0x8b>
    8a92:       75 0a                   jne    8a9e <sdhci_suspend_host+0x9e>
    8a98:       0f 84 87 00 00 00       je     8b25 <sdhci_suspend_host+0x125>
    8aa5:       74 90                   je     8a37 <sdhci_suspend_host+0x37>
    8ab8:       0f 85 f5 00 00 00       jne    8bb3 <sdhci_suspend_host+0x1b3>
    8ad8:       0f 85 c0 00 00 00       jne    8b9e <sdhci_suspend_host+0x19e>
    8af0:       0f 85 93 00 00 00       jne    8b89 <sdhci_suspend_host+0x189>
    8b06:       e8 00 00 00 00          call   8b0b <sdhci_suspend_host+0x10b>
    8b14:       0f 85 1d ff ff ff       jne    8a37 <sdhci_suspend_host+0x37>
    8b20:       e9 00 00 00 00          jmp    8b25 <sdhci_suspend_host+0x125>
    8b25:       e8 00 00 00 00          call   8b2a <sdhci_suspend_host+0x12a>
    8b2c:       75 52                   jne    8b80 <sdhci_suspend_host+0x180>
    8b53:       e9 55 ff ff ff          jmp    8aad <sdhci_suspend_host+0xad>
    8b62:       e8 00 00 00 00          call   8b67 <sdhci_suspend_host+0x167>
    8b67:       e9 ef fe ff ff          jmp    8a5b <sdhci_suspend_host+0x5b>
    8b76:       e8 00 00 00 00          call   8b7b <sdhci_suspend_host+0x17b>
    8b7b:       e9 f5 fe ff ff          jmp    8a75 <sdhci_suspend_host+0x75>
    8b84:       e9 15 ff ff ff          jmp    8a9e <sdhci_suspend_host+0x9e>
    8b94:       e8 00 00 00 00          call   8b99 <sdhci_suspend_host+0x199>
    8b99:       e9 60 ff ff ff          jmp    8afe <sdhci_suspend_host+0xfe>
    8ba9:       e8 00 00 00 00          call   8bae <sdhci_suspend_host+0x1ae>
    8bae:       e9 32 ff ff ff          jmp    8ae5 <sdhci_suspend_host+0xe5>
    8bbb:       e8 00 00 00 00          call   8bc0 <sdhci_suspend_host+0x1c0>
    8bc0:       e9 03 ff ff ff          jmp    8ac8 <sdhci_suspend_host+0xc8>
$ 

> at the same time gives developer less uglified (by ifdeffery) code.
> It means there is less risk to miss anything of that which make become
> a compile-time warning of unused function, or even issues during linking
> with modules, etc.
> 
> Should I update a commit message with that?