On Mon, May 25, 2020 at 6:36 AM John Hubbard <jhubbard@xxxxxxxxxx> wrote: > > On 2020-05-23 21:27, Souptick Joarder wrote: > > API __get_user_pages_fast() renamed to get_user_pages_fast_only() > > to align with pin_user_pages_fast_only(). > > > > As part of this we will get rid of write parameter. Instead caller > > will pass FOLL_WRITE to get_user_pages_fast_only(). This will not > > change any existing functionality of the API. > > > > All the callers are changed to pass FOLL_WRITE. > > This looks good. A few nits below, but with those fixed, feel free to > add: > > Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> > > > > > There are few places where 1 is passed to 2nd parameter of > > __get_user_pages_fast() and return value is checked for 1 > > like [1]. Those are replaced with new inline > > get_user_page_fast_only(). > > > > [1] if (__get_user_pages_fast(hva, 1, 1, &page) == 1) > > > > We try to avoid talking *too* much about the previous version of > the code. Just enough. So, instead of the above two paragraphs, > I'd compress it down to: > > Also: introduce get_user_page_fast_only(), and use it in a few > places that hard-code nr_pages to 1. > > ... > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 93d93bd..8d4597f 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -1817,10 +1817,16 @@ extern int mprotect_fixup(struct vm_area_struct *vma, > > /* > > * doesn't attempt to fault and will return short. > > */ > > -int __get_user_pages_fast(unsigned long start, int nr_pages, int write, > > - struct page **pages); > > +int get_user_pages_fast_only(unsigned long start, int nr_pages, > > + unsigned int gup_flags, struct page **pages); > > Silly nit: > > Can you please leave the original indentation in place? I don't normally > comment about this, but I like the original indentation better, and it matches > the pin_user_pages_fast() below, too. > > ... > > @@ -2786,8 +2792,8 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages, > > * If the architecture does not support this function, simply return with no > > * pages pinned. > > */ > > -int __get_user_pages_fast(unsigned long start, int nr_pages, int write, > > - struct page **pages) > > +int get_user_pages_fast_only(unsigned long start, int nr_pages, > > + unsigned int gup_flags, struct page **pages) > > > Same thing here: you've changed the original indentation, which was (arguably, but > to my mind anyway) more readable, and for no reason. It still would have fit within > 80 cols. > > I'm sure it's a perfect 50/50 mix of people who prefer either indentation style, and > so for brand new code, I'll remain silent, as long as it is consistent with either > itself and/or the surrounding code. But changing it back and forth is a bit > aggravating, and best avoided. :) Ok, along with these changes I will remove the *RFC* tag and repost it.
