Hi,
Thanks mate. I have got a working program now.
You guys in this list are just great :)
Regards,
Naren
On Fri, 17 Sep 2004 matrix reloaded wrote :
> Hi,
> first of let me know why you are allocating space for the new vma, as
>find_vma will return a pointer to the existing vma and in that case you'll create a
>memory leak there, as you will lose the track for the allocated vma in case if one
>vma is returned by find_vma() ;-)
>
>I think to spilt a vma you can use the functionality explained in
>madvise_fixup_start(), madvise_fixup_end or madvise_fixup_middle() functions
>defined in mm/filemap.c... go through them, I think it'll solve your problem.
>
>Thanks.
>Sumit Sharma.
>
>On Thu, 16 Sep 2004 Naren wrote :
> >Hi,
> >I am trying to write a system call that splits a VMA into two halves. The problem
>is that, as I am using do_mmap() system call, it is only creating one area and that
>too at a different address than the old one.
> >
> >The code:
> >(*addr is passed as some arbitrary address that falls in any VMA)
> >
> >struct mm_struct *mm = current->mm;
> >struct vm_area_struct *vma;
> >unsigned long ret, ret2, old_length,length, start_add, end_add, second_add;
> >
> >
> > if (flag == 0) {
> > vma = (struct vm_area_struct *) kmalloc(sizeof(struct
>vm_area_struct));
> > vma = find_vma(mm, *addr);
> > if (vma == NULL){
> > return ENOMEM;
> > }
> > old_length = (vma->vm_end - vma->vm_start);
> > length = old_length/2;
> > start_add = PAGE_ALIGN(vma->vm_start);
> > end_add = PAGE_ALIGN(vma->vm_end);
> > second_add = PAGE_ALIGN(start_add + length);
> > ret = do_mremap(start_add, old_length, length, NULL, NULL);
> > ret2 = do_mmap(NULL, second_add, length, PROT_READ,
>MAP_EXECUTABLE, 0);
> >
> > }
> >
> >
> >Is there anything that i m doing wrong over here ..
> >
> >Thanks and Regards,
> >Narinder
> >
