Messages in this thread | | | Date | Wed, 9 Sep 2015 18:26:05 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] mm/mmap.c: Remove useless statement "vma = NULL" in find_vma() |
| |
On 09/08, Chen Gang wrote: > > I also want to consult: the comments of find_vma() says:
Sorry, I don't understand the question ;)
> "Look up the first VMA which satisfies addr < vm_end, ..." > > Is it OK?
Why not?
> (why not "vm_start <= addr < vm_end"),
Because this some callers actually want to find the 1st vma which satisfies addr < vm_end? For example, shift_arg_pages().
OTOH, I think that another helper,
find_vma_xxx(mm, addr) { vma = find_vma(...) if (vma && vma->vm_start > addr) vma = NULL; return vma; }
makes sense. It can have a lot of users.
> need we let "vma = tmp" > in "if (tmp->vm_start <= addr)"? -- it looks the comments is not match > the implementation, precisely (maybe not 1st VMA).
This contradicts with above... I mean, it is not clear what exactly do you blame, semantics or implementation.
The implementation looks correct. Why do you think it can be not 1st vma?
Oleg.
| |