Re: [PATCH] [PATCH] VERIFY_OCTAL_PERMISSIONS: Move to <linux/sysfs.h> where it belongs

[Andrew Morton <akpm@linux-foundation.org>]

On 5 Dec 2014 20:18:02 -0500 "George Spelvin" <linux@horizon.com> wrote:

> > VERIFY_OCTAL_PERMISSIONS() sticks out like a sore thumb in kernel.h. 
> > How about we move it into sysfs.h?
> 
> Something like this, you mean?

Kinda.

> The <linux/types.h> in moduleparam.h is needed for one function
> prototype that passes s16 parameters.  My first reaction is
> to wonder if that can be gotten rid of, too.
> 
> -----

This shouldn't be here because "^---" is considered "end of changelog".

> It's the only user of <linux/bug.h> in kernel.h, so that reduces
> the compile-time cost of #include <linux/kernel.h>
> 
> One necessary consequent change in <linux/moduleparam.h>.
>
> Suggested-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: George Spelvin <linux@horizon.com>
>
> ...
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 3d770f55..07080aa2 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -804,14 +804,4 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
>  # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
>  #endif
>  
> -/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
> -#define VERIFY_OCTAL_PERMISSIONS(perms)					\
> -	(BUILD_BUG_ON_ZERO((perms) < 0) +				\
> -	 BUILD_BUG_ON_ZERO((perms) > 0777) +				\
> -	 /* User perms >= group perms >= other perms */			\
> -	 BUILD_BUG_ON_ZERO(((perms) >> 6) < (((perms) >> 3) & 7)) +	\
> -	 BUILD_BUG_ON_ZERO((((perms) >> 3) & 7) < ((perms) & 7)) +	\
> -	 /* Other writable?  Generally considered a bad idea. */	\
> -	 BUILD_BUG_ON_ZERO((perms) & 2) +				\
> -	 (perms))
>  #endif
> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> index f97d0dbb..9f213542 100644
> --- a/include/linux/sysfs.h
> +++ b/include/linux/sysfs.h
> @@ -70,6 +70,17 @@ struct attribute_group {
>   * for examples..
>   */
>  
> +/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
> +#define VERIFY_OCTAL_PERMISSIONS(perms)					\
> +	(BUILD_BUG_ON_ZERO((perms) < 0) +				\
> +	 BUILD_BUG_ON_ZERO((perms) > 0777) +				\
> +	 /* User perms >= group perms >= other perms */			\
> +	 BUILD_BUG_ON_ZERO(((perms) >> 6) < (((perms) >> 3) & 7)) +	\
> +	 BUILD_BUG_ON_ZERO((((perms) >> 3) & 7) < ((perms) & 7)) +	\
> +	 /* Other writable?  Generally considered a bad idea. */	\
> +	 BUILD_BUG_ON_ZERO((perms) & 2) +				\
> +	 (perms))
> +

Let's include bug.h into sysfs.h.

>  #define __ATTR(_name, _mode, _show, _store) {				\
>  	.attr = {.name = __stringify(_name),				\
>  		 .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },		\
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> index 1c9effa2..974097df 100644
> --- a/include/linux/moduleparam.h
> +++ b/include/linux/moduleparam.h
> @@ -1,9 +1,9 @@
>  #ifndef _LINUX_MODULE_PARAMS_H
>  #define _LINUX_MODULE_PARAMS_H
>  /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
> -#include <linux/init.h>
>  #include <linux/stringify.h>
> -#include <linux/kernel.h>
> +#include <linux/sysfs.h>
> +#include <linux/types.h>

Removing the kernel.h inclusion is good, but risky.  Are you sure
there's nothing in moduleparam.h which uses kernel.h things?


>  /* You can override this manually, but generally this should match the
>     module name. */