Messages in this thread | | | Date | Tue, 22 Apr 2008 08:12:11 -0700 | From | Randy Dunlap <> | Subject | Re: [RFC] Introduce __ARCH_WANT_SYS_SYSFS |
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On Tue, 22 Apr 2008 13:13:39 +0100 Will Newton wrote:
> Hi, > > This patch introduces a __ARCH_WANT_SYS_SYSFS #define for > architectures that support the sysfs(2) system call. At the moment > that's everybody but blackfin, but future architectures may want to > save the (admittedly small) code size that it adds to the kernel as > well. > > (patch attached as well as inline because gmail seems to mangle my whitespace) > > --- > >From d0746366e8ccb5fbaa6c9945540cecbe0c421222 Mon Sep 17 00:00:00 2001 > From: Will Newton <will.newton@imgtec.com> > Date: Tue, 22 Apr 2008 12:57:03 +0100 > Subject: [PATCH] Introduce __ARCH_WANT_SYS_SYSFS. > > Signed-off-by: Will Newton <will.newton@imgtec.com> > > All arches that want the sysfs(2) system call should define this symbol. > Arches such as blackfin that do not implement the system call don't compile > the code and save some small amount of space.
Is there any reason that this couldn't (and shouldn't) be done in the Kconfig space and done as documented in Documentation/kbuild/kconfig-language.txt ?
<quote:> Adding common features and make the usage configurable ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ It is a common idiom to implement a feature/functionality that are relevant for some architectures but not all. The recommended way to do so is to use a config variable named HAVE_* that is defined in a common Kconfig file and selected by the relevant architectures. An example is the generic IOMAP functionality.
We would in lib/Kconfig see:
# Generic IOMAP is used to ... config HAVE_GENERIC_IOMAP
config GENERIC_IOMAP depends on HAVE_GENERIC_IOMAP && FOO
And in lib/Makefile we would see: obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
For each architecture using the generic IOMAP functionality we would see:
config X86 select ... select HAVE_GENERIC_IOMAP select ...
--- ~Randy
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