On Fri, 4 Feb 2005, Linus Torvalds wrote:
>
> Would arch maintainers please look at fixing this in their architectures
> instead? Make TASK_SIZE be the maximum size a process VM can have.
Actually, thinking more about it, maybe the right idea (to avoid
confusion) is to walk away from TASK_SIZE entirely.
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.
(This also assumes that we would make mm_segment_t just be "unsigned
long", and stop playing games with segments looking like they were used a
few hundred million years ago in the paleozoic era Linux kernel. It made
sense back when we did that long-ago conversion, it doesn't seem to make
much sense any more ;).
Linus
