Messages in this thread | | | From | Kim Kyuwon <> | Date | Sat, 9 May 2009 12:56:51 +0900 | Subject | Re: Input: add MAX7359 key switch controller driver |
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On Sat, May 9, 2009 at 12:36 PM, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > Hi Kim, > > On Friday 08 May 2009 18:58:45 Kim Kyuwon wrote: >> By the way, can I ask the same question which I ask to Trilok. >> Even though I guard suspend/resume with #ifdef CONFIG_PM in the new >> patch, Could I know the good reason for this protection? Because >> '/Documentation/SubmittingPatches' says "ifdefs are ugly" > > If kernel is compiled without CONFIG_PM then these functions would > be just dead weight. Generally speaking, #ifdefs are considered ugly > if they are in the middle of function code, affecting logic. But to > to compile out unneeded functionality they are OK. That's why you > often see in the kernel > > #ifdef CONFIG_BAZ > void do_baz() > { > .. real code .. > } > #else > void do_baz() > { > } > #endif > > and then... > > int foo() > { > bar1(); > bar2(); > do_baz(); > bar3(); > } > > > As you can see, foo()'s logic stays the same, there are no #ifdefs > cluttering it, but baz code either executed or not. > > Hope this helps.
Thank you for your kind explanation. It is very helpful to me and my colleagues.
Kyuwon
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