Re: [PATCH v2 01/26] mm: gup: rename "nonblocking" to "locked" where proper

Jerome Glisse
2019-02-21T15:17:58Z

On Tue, Feb 12, 2019 at 10:56:07AM +0800, Peter Xu wrote:
> There's plenty of places around __get_user_pages() that has a parameter
> "nonblocking" which does not really mean that "it won't block" (because
> it can really block) but instead it shows whether the mmap_sem is
> released by up_read() during the page fault handling mostly when
> VM_FAULT_RETRY is returned.
>
> We have the correct naming in e.g. get_user_pages_locked() or
> get_user_pages_remote() as "locked", however there're still many places
> that are using the "nonblocking" as name.
>
> Renaming the places to "locked" where proper to better suite the
> functionality of the variable. While at it, fixing up some of the
> comments accordingly.
>
> Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Minor issue see below

Reviewed-by: Jérôme Glisse <jglisse@redhat.com>

[...]

> @@ -656,13 +656,11 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
> * appropriate) must be called after the page is finished with, and
> * before put_page is called.
> *
> - * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
> - * or mmap_sem contention, and if waiting is needed to pin all pages,
> - * *@nonblocking will be set to 0. Further, if @gup_flags does not
> - * include FOLL_NOWAIT, the mmap_sem will be released via up_read() in
> - * this case.
> + * If @locked != NULL, *@locked will be set to 0 when mmap_sem is
> + * released by an up_read(). That can happen if @gup_flags does not
> + * has FOLL_NOWAIT.

I am not a native speaker but i believe the correct wording is:
@gup_flags does not have FOLL_NOWAIT