Messages in this thread | | | Date | Sun, 30 Dec 2018 18:50:02 +0100 | From | LEROY Christophe <> | Subject | Re: [PATCH v8 01/25] scsi/atari_scsi: Don't select CONFIG_NVRAM |
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Arnd Bergmann <arnd@arndb.de> a écrit :
> On Sat, Dec 29, 2018 at 3:51 AM Michael Schmitz <schmitzmic@gmail.com> wrote: >> >> Hi Finn, >> >> Am 29.12.2018 um 15:34 schrieb Finn Thain: >> > On Sat, 29 Dec 2018, Michael Schmitz wrote: >> > >> >> >> >> IS_BUILTIN(CONFIG_NVRAM) is probably what Christophe really >> meant to suggest. >> >> >> >> Or (really going out on a limb here): >> >> >> >> IS_BUILTIN(CONFIG_NVRAM) || >> >> ( IS_MODULE(CONFIG_ATARI_SCSI) && IS_ENABLED(CONFIG_NVRAM) ) >> >> >> >> Not that I'd advocate that, for this series. >> >> >> > >> > Well, you are a maintainer for atari_scsi.c. >> > >> > Are you saying that you want IS_BUILTIN(CONFIG_NVRAM) used here instead of >> > ifdef? >> >> No, just pointing out that there would be a way to avoid the ifdef >> without messing up driver behaviour. I'm fine with the ifdef - not least >> because it clearly eliminates code that would be unreachable. >> >> (On second thought - I don't want to speculate whether there's weird >> compiler options that could result in the nvram_check_checksum and >> nvram_read_bytes symbols to still be referenced in the final link, even >> though IS_BUILTIN(CONFIG_NVRAM) always evaluates to false. Best leave >> this as-is.) > > As far as I know, it's totally reliable with the supported compilers > (gcc-4.6+). > In the older compilers (e.g. 4.1), there was a corner case, where it could > have failed to eliminate a function that was only referenced through > a pointer > from a discarded variable, but a plain IS_ENABLED() check like the one here > was still ok, and lots of code relies on that. > > Other than that, I agree either way is totally fine here, so no objections > to using the #ifdef.
As far as I know, kernel codying style promotes the use of IS_ENABLED() etc. instead of #ifdefs when possible.
Christophe
> > Arnd
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