Re: [patch 19/24] TASK_SIZE is variable.

[Russell King <rmk@arm.linux.org.uk>]

On Fri, Feb 04, 2005 at 07:29:17PM -0800, Linus Torvalds wrote:
> For example, replacing TASK_SIZE in fs/namei.c with "thread->addr_limit" 
> would actually clean up the code: it would mean that the games with 
> "get_fs()" etc would just go away, to be replaced with something like
> 
> 	unsigned long len;
> 	unsigned long limit = current_thread_info()->addr_limit;
> 
> 	if ((unsigned long) filename >= limit)
> 		return -EFAULT;
> 	len = limit - (unsigned long) filename;
> 	if (len > PATH_MAX)
> 		len = PATH_MAX;
> 
> which looks cleaner.

Except that "addr_limit" may be defined by an architecture to be zero
(which can be interpreted as 4GB by the arch specific code) for the
case where we allow kernel mode access.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core