Re: [PATCH] bitmap: parse input from kernel and user buffers

["Inaky Perez-Gonzalez" <inaky@linux.intel.com>]

Reinette Chatre wrote:
> lib/bitmap.c:bitmap_parse() is a library function that received as
> input a user buffer. This seemed to have originated from the way
> the write_proc function of the /proc filesystem operates.
>
> This has been reworked to not use kmalloc and eliminates a lot
> of get_user() overhead by performing one access_ok before using
> __get_user().
> We need to test if we are in kernel or user space (is_user) and access
> the buffer differently. We cannot use __get_user() to access kernel
> addresses in all cases, for example in architectures with separate
> address space for kernel and user.
>
> This function will be useful for other uses as well; for example,
> taking input  for /sysfs instead of /proc, so it was changed to accept
> kernel buffers. We have this use for the Linux UWB project, as part
> as the upcoming bandwidth allocator code.
>
> Only a few routines used this function and they were changed too.
>
> Signed-off-by: Reinette Chatre <reinette.chatre@linux.intel.com>
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>