2022-01-10 04:25:47

by Matthew Wilcox

Subject: [PATCH v2 01/28] gup: Remove for_each_compound_range()

This macro doesn't simplify the users; it's easier to just call
compound_range_next() inside the loop.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
---
mm/gup.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 2c51e9748a6a..7a07e0c00bf5 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -236,9 +236,6 @@ static inline void compound_range_next(unsigned long i, unsigned long npages,
struct page *next, *page;
unsigned int nr = 1;

- if (i >= npages)
- return;
-
next = *list + i;
page = compound_head(next);
if (PageCompound(page) && compound_order(page) >= 1)
@@ -249,12 +246,6 @@ static inline void compound_range_next(unsigned long i, unsigned long npages,
*ntails = nr;
}

-#define for_each_compound_range(__i, __list, __npages, __head, __ntails) \
- for (__i = 0, \
- compound_range_next(__i, __npages, __list, &(__head), &(__ntails)); \
- __i < __npages; __i += __ntails, \
- compound_range_next(__i, __npages, __list, &(__head), &(__ntails)))
-
static inline void compound_next(unsigned long i, unsigned long npages,
struct page **list, struct page **head,
unsigned int *ntails)
@@ -371,7 +362,8 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
struct page *head;
unsigned int ntails;

- for_each_compound_range(index, &page, npages, head, ntails) {
+ for (index = 0; index < npages; index += ntails) {
+ compound_range_next(index, npages, &page, &head, &ntails);
if (make_dirty && !PageDirty(head))
set_page_dirty_lock(head);
put_compound_head(head, ntails, FOLL_PIN);
--
2.33.0

2022-01-10 08:23:07

by Christoph Hellwig

Subject: Re: [PATCH v2 01/28] gup: Remove for_each_compound_range()

On Mon, Jan 10, 2022 at 04:23:39AM +0000, Matthew Wilcox (Oracle) wrote:
> This macro doesn't simplify the users; it's easier to just call
> compound_range_next() inside the loop.
>
> Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>

2022-01-11 01:07:19

by John Hubbard

Subject: Re: [PATCH v2 01/28] gup: Remove for_each_compound_range()

On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote:
> This macro doesn't simplify the users; it's easier to just call
> compound_range_next() inside the loop.
>
> Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
> ---
> mm/gup.c | 12 ++----------
> 1 file changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 2c51e9748a6a..7a07e0c00bf5 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -236,9 +236,6 @@ static inline void compound_range_next(unsigned long i, unsigned long npages,
> struct page *next, *page;
> unsigned int nr = 1;
>
> - if (i >= npages)
> - return;
> -
> next = *list + i;
> page = compound_head(next);
> if (PageCompound(page) && compound_order(page) >= 1)
> @@ -249,12 +246,6 @@ static inline void compound_range_next(unsigned long i, unsigned long npages,
> *ntails = nr;
> }
>
> -#define for_each_compound_range(__i, __list, __npages, __head, __ntails) \
> - for (__i = 0, \
> - compound_range_next(__i, __npages, __list, &(__head), &(__ntails)); \
> - __i < __npages; __i += __ntails, \
> - compound_range_next(__i, __npages, __list, &(__head), &(__ntails)))
> -

Yes!! Thank you.

> static inline void compound_next(unsigned long i, unsigned long npages,
> struct page **list, struct page **head,
> unsigned int *ntails)
> @@ -371,7 +362,8 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
> struct page *head;
> unsigned int ntails;
>
> - for_each_compound_range(index, &page, npages, head, ntails) {
> + for (index = 0; index < npages; index += ntails) {
> + compound_range_next(index, npages, &page, &head, &ntails);

And now the code is more "honest and up front": items that are changed are
passed by reference, and one can see right here what those are.


> if (make_dirty && !PageDirty(head))
> set_page_dirty_lock(head);
> put_compound_head(head, ntails, FOLL_PIN);

Reviewed-by: John Hubbard <[email protected]>


thanks,
--
John Hubbard
NVIDIA