From e52eec13cd6b7f30ab19081b387813e03e592ae5 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 8 Sep 2010 16:54:17 +0200 Subject: SYSFS: Allow boot time switching between deprecated and modern sysfs layout I have some systems which need legacy sysfs due to old tools that are making assumptions that a directory can never be a symlink to another directory, and it's a big hazzle to compile separate kernels for them. This patch turns CONFIG_SYSFS_DEPRECATED into a run time option that can be switched on/off the kernel command line. This way the same binary can be used in both cases with just a option on the command line. The old CONFIG_SYSFS_DEPRECATED_V2 option is still there to set the default. I kept the weird name to not break existing config files. Also the compat code can be still completely disabled by undefining CONFIG_SYSFS_DEPRECATED_SWITCH -- just the optimizer takes care of this now instead of lots of ifdefs. This makes the code look nicer. v2: This is an updated version on top of Kay's patch to only handle the block devices. I tested it on my old systems and that seems to work. Cc: axboe@kernel.dk Signed-off-by: Andi Kleen Cc: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- include/linux/device.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/device.h b/include/linux/device.h index 516fecacf27b..dd4895313468 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -751,4 +751,11 @@ do { \ MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor)) #define MODULE_ALIAS_CHARDEV_MAJOR(major) \ MODULE_ALIAS("char-major-" __stringify(major) "-*") + +#ifdef CONFIG_SYSFS_DEPRECATED +extern long sysfs_deprecated; +#else +#define sysfs_deprecated 0 +#endif + #endif /* _DEVICE_H_ */ -- cgit v1.2.3-59-g8ed1b