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. :)
thanks,
--
John Hubbard
NVIDIA
