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


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@xxxxxxxxxxxxxxx>
Signed-off-by: Inaky Perez-Gonzalez <inaky@xxxxxxxxxxxxxxx>
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