Subject: Re: [net-next PATCH v4 2/3] sysctl: add proc_dobitmap

From: Cong Wang <[email-masked]>
Date: Tue, 16 Feb 2010 17:12:32 +0800

Octavian Purdila wrote:
> The new function can be used to update bitmaps via /proc. Bits can be
> set by writing positive values in the file and cleared by writing
> negative values (e.g. 0 2 will set bits 1 and 3, -0 -2 will clear
> them). Reading will show only the set bits.
> 
> Signed-off-by: Octavian Purdila <[email-masked]>
> Cc: WANG Cong <[email-masked]>
> Cc: Eric W. Biederman <[email-masked]>
> ---
>  include/linux/sysctl.h |    2 +
>  kernel/sysctl.c        |   76 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 78 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index 9f236cd..ba89bf2 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -985,6 +985,8 @@ extern int proc_doulongvec_minmax(struct ctl_table *, int,
>  				  void __user *, size_t *, loff_t *);
>  extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
>  				      void __user *, size_t *, loff_t *);
> +extern int proc_dobitmap(struct ctl_table *, int,
> +			 void __user *, size_t *, loff_t *);
>  
>  /*
>   * Register a set of sysctl names by calling register_sysctl_table
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index b0f9618..b8959f4 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2596,6 +2596,82 @@ static int proc_do_cad_pid(struct ctl_table *table, int write,
>  	return 0;
>  }
>  
> +/**
> + * proc_dobitmap - read/write from/to a bitmap
> + * @table: the sysctl table
> + * @write: %TRUE if this is a write to the sysctl file
> + * @buffer: the user buffer
> + * @lenp: the size of the user buffer
> + * @ppos: file position
> + * @ppos: the current position in the file

Duplicated.

I hope Eric can also comment on these two patches.