Re: __get_user usage in mm/slab.c

[vinolin <vinolin@nodeinfotech.com>]

On Tuesday 12 March 2002 17:28, Roman Zippel wrote:
> Hi,
>
> The way __get_user is currently used in mm/slab.c is not portable. It
> breaks on arch which have seperate user/kernel memory space. It still
> works during boot or from kernel threads, but /proc/slabinfo shows only
> broken entries or if a module creates a slab cache, I got lots of
> warnings.
> We have to at least insert a "set_fs(get_fs())", but IMO a separate
> interface would be better. Any opinions?
>
> bye, Roman

Hi !

I guess u need to read user space from kernel sapce.
You can use the sys_call_table functions for this.
For example, u can use the following code in your file to open a user space 
file from kernel space.

#define BEGIN_KMEM {mm_segment_t old_fs=get_fs();set_fs(get_ds());
#define END_KMEM set_fs(old_fs);}
int (*sample_open)(char *, int);

sample_open = sys_call_table[SYS_open];
BEGIN_KMEM
sample_open("/home/samplefile.txt",O_RDWR);
/* the same way close , read , write etc. can be  written */
END_KMEM

Regards,
Vinolin.