[PATCH v2 0/9] Convert several functions in page_io.c to use a folio

[PATCH v2 0/9] Convert several functions in page_io.c to use a folio

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

This patch series converts several functions in page_io.c to use a
folio, which can remove several implicit calls to compound_head().

Changelog:

v2:
- remove unneeded ClearPageUptodate() and SetPageError(), suggested by
  Matthew Wilcox
- convert bio_first_page_all() to bio_first_folio_all(), suggested by
  Matthew Wilcox
- convert PageTransHuge to folio_test_pmd_mappable per Matthew Wilcox

ZhangPeng (9):
  mm/page_io: remove unneeded ClearPageUptodate()
  mm/page_io: remove unneeded SetPageError()
  mm/page_io: convert bio_first_page_all() to bio_first_folio_all()
  mm/page_io: use a folio in __end_swap_bio_read()
  mm/page_io: use a folio in sio_read_complete()
  mm/page_io: use a folio in swap_writepage_bdev_sync()
  mm/page_io: use a folio in swap_writepage_bdev_async()
  mm/page_io: convert count_swpout_vm_event() to take in a folio
  mm/page_io: convert bio_associate_blkg_from_page() to take in a folio

 Documentation/block/biovecs.rst  |  2 +-
 drivers/block/drbd/drbd_bitmap.c |  2 +-
 fs/f2fs/data.c                   |  2 +-
 include/linux/bio.h              |  4 +--
 kernel/power/swap.c              |  2 +-
 mm/page_io.c                     | 55 +++++++++++++++-----------------
 6 files changed, 32 insertions(+), 35 deletions(-)

-- 
2.25.1

[PATCH v2 1/9] mm/page_io: remove unneeded ClearPageUptodate()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

The VM_BUG_ON_FOLIO in swap_readpage() ensures that the page is already
!uptodate in __end_swap_bio_read() and sio_read_complete().
Just remove unneeded ClearPageUptodate().

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 mm/page_io.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 8741d3a0d48a..3087a69a014b 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -62,7 +62,6 @@ static void __end_swap_bio_read(struct bio *bio)
 
 	if (bio->bi_status) {
 		SetPageError(page);
-		ClearPageUptodate(page);
 		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
 				     MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
 				     (unsigned long long)bio->bi_iter.bi_sector);
@@ -417,7 +416,6 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
 			struct page *page = sio->bvec[p].bv_page;
 
 			SetPageError(page);
-			ClearPageUptodate(page);
 			unlock_page(page);
 		}
 		pr_alert_ratelimited("Read-error on swap-device\n");
-- 
2.25.1

[PATCH v2 2/9] mm/page_io: remove unneeded SetPageError()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Nobody checks the PageError()/folio_test_error() for the page/folio in
__end_swap_bio_read/write() and sio_write_complete(). Therefore, we
don't need to set the error flag. Just drop it.

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 mm/page_io.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 3087a69a014b..5ddb5d9c5013 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -32,7 +32,6 @@ static void __end_swap_bio_write(struct bio *bio)
 	struct page *page = bio_first_page_all(bio);
 
 	if (bio->bi_status) {
-		SetPageError(page);
 		/*
 		 * We failed to write the page out to swap-space.
 		 * Re-dirty the page in order to avoid it being reclaimed.
@@ -61,7 +60,6 @@ static void __end_swap_bio_read(struct bio *bio)
 	struct page *page = bio_first_page_all(bio);
 
 	if (bio->bi_status) {
-		SetPageError(page);
 		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
 				     MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
 				     (unsigned long long)bio->bi_iter.bi_sector);
@@ -415,7 +413,6 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
 		for (p = 0; p < sio->pages; p++) {
 			struct page *page = sio->bvec[p].bv_page;
 
-			SetPageError(page);
 			unlock_page(page);
 		}
 		pr_alert_ratelimited("Read-error on swap-device\n");
-- 
2.25.1

[PATCH v2 3/9] mm/page_io: convert bio_first_page_all() to bio_first_folio_all()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Convert bio_first_page_all() to bio_first_folio_all() to return a
folio, which makes it easier to use.

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 Documentation/block/biovecs.rst  | 2 +-
 drivers/block/drbd/drbd_bitmap.c | 2 +-
 fs/f2fs/data.c                   | 2 +-
 include/linux/bio.h              | 4 ++--
 kernel/power/swap.c              | 2 +-
 mm/page_io.c                     | 4 ++--
 6 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Documentation/block/biovecs.rst b/Documentation/block/biovecs.rst
index ddb867e0185b..258f6faed333 100644
--- a/Documentation/block/biovecs.rst
+++ b/Documentation/block/biovecs.rst
@@ -133,7 +133,7 @@ Usage of helpers:
 	bio_for_each_segment_all()
 	bio_for_each_bvec_all()
 	bio_first_bvec_all()
-	bio_first_page_all()
+	bio_first_folio_all()
 	bio_last_bvec_all()
 
 * The following helpers iterate over single-page segment. The passed 'struct
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 85ca000a0564..ce1a07ba85ff 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -939,7 +939,7 @@ static void drbd_bm_endio(struct bio *bio)
 	struct drbd_bm_aio_ctx *ctx = bio->bi_private;
 	struct drbd_device *device = ctx->device;
 	struct drbd_bitmap *b = device->bitmap;
-	unsigned int idx = bm_page_to_idx(bio_first_page_all(bio));
+	unsigned int idx = bm_page_to_idx(&bio_first_folio_all(bio)->page);
 
 	if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
 	    !bm_test_page_unchanged(b->bm_pages[idx]))
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 5882afe71d82..6706858de984 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -288,7 +288,7 @@ static void f2fs_post_read_work(struct work_struct *work)
 
 static void f2fs_read_end_io(struct bio *bio)
 {
-	struct f2fs_sb_info *sbi = F2FS_P_SB(bio_first_page_all(bio));
+	struct f2fs_sb_info *sbi = F2FS_P_SB(&bio_first_folio_all(bio)->page);
 	struct bio_post_read_ctx *ctx;
 	bool intask = in_task();
 
diff --git a/include/linux/bio.h b/include/linux/bio.h
index c4f5b5228105..7d2979d24530 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -248,9 +248,9 @@ static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
 	return bio->bi_io_vec;
 }
 
-static inline struct page *bio_first_page_all(struct bio *bio)
+static inline struct folio *bio_first_folio_all(struct bio *bio)
 {
-	return bio_first_bvec_all(bio)->bv_page;
+	return page_folio(bio_first_bvec_all(bio)->bv_page);
 }
 
 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index f6ebcd00c410..2796ce48ca4b 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -247,7 +247,7 @@ static void hib_finish_batch(struct hib_bio_batch *hb)
 static void hib_end_io(struct bio *bio)
 {
 	struct hib_bio_batch *hb = bio->bi_private;
-	struct page *page = bio_first_page_all(bio);
+	struct page *page = &bio_first_folio_all(bio)->page;
 
 	if (bio->bi_status) {
 		pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
diff --git a/mm/page_io.c b/mm/page_io.c
index 5ddb5d9c5013..e21d570c873d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -29,7 +29,7 @@
 
 static void __end_swap_bio_write(struct bio *bio)
 {
-	struct page *page = bio_first_page_all(bio);
+	struct page *page = &bio_first_folio_all(bio)->page;
 
 	if (bio->bi_status) {
 		/*
@@ -57,7 +57,7 @@ static void end_swap_bio_write(struct bio *bio)
 
 static void __end_swap_bio_read(struct bio *bio)
 {
-	struct page *page = bio_first_page_all(bio);
+	struct page *page = &bio_first_folio_all(bio)->page;
 
 	if (bio->bi_status) {
 		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
-- 
2.25.1

[PATCH v2 4/9] mm/page_io: use a folio in __end_swap_bio_read()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Saves one implicit call to compound_head().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 mm/page_io.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index e21d570c873d..6520687bd282 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -57,16 +57,16 @@ static void end_swap_bio_write(struct bio *bio)
 
 static void __end_swap_bio_read(struct bio *bio)
 {
-	struct page *page = &bio_first_folio_all(bio)->page;
+	struct folio *folio = bio_first_folio_all(bio);
 
 	if (bio->bi_status) {
 		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
 				     MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
 				     (unsigned long long)bio->bi_iter.bi_sector);
 	} else {
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	}
-	unlock_page(page);
+	folio_unlock(folio);
 }
 
 static void end_swap_bio_read(struct bio *bio)
-- 
2.25.1

[PATCH v2 5/9] mm/page_io: use a folio in sio_read_complete()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Saves one implicit call to compound_head().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 mm/page_io.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 6520687bd282..92f21f380ee8 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -403,17 +403,17 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
 
 	if (ret == sio->len) {
 		for (p = 0; p < sio->pages; p++) {
-			struct page *page = sio->bvec[p].bv_page;
+			struct folio *folio = page_folio(sio->bvec[p].bv_page);
 
-			SetPageUptodate(page);
-			unlock_page(page);
+			folio_mark_uptodate(folio);
+			folio_unlock(folio);
 		}
 		count_vm_events(PSWPIN, sio->pages);
 	} else {
 		for (p = 0; p < sio->pages; p++) {
-			struct page *page = sio->bvec[p].bv_page;
+			struct folio *folio = page_folio(sio->bvec[p].bv_page);
 
-			unlock_page(page);
+			folio_unlock(folio);
 		}
 		pr_alert_ratelimited("Read-error on swap-device\n");
 	}
-- 
2.25.1

[PATCH v2 6/9] mm/page_io: use a folio in swap_writepage_bdev_sync()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Saves one implicit call to compound_head().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/page_io.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 92f21f380ee8..0c96ea9dd258 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -331,6 +331,7 @@ static void swap_writepage_bdev_sync(struct page *page,
 {
 	struct bio_vec bv;
 	struct bio bio;
+	struct folio *folio = page_folio(page);
 
 	bio_init(&bio, sis->bdev, &bv, 1,
 		 REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc));
@@ -340,8 +341,8 @@ static void swap_writepage_bdev_sync(struct page *page,
 	bio_associate_blkg_from_page(&bio, page);
 	count_swpout_vm_event(page);
 
-	set_page_writeback(page);
-	unlock_page(page);
+	folio_start_writeback(folio);
+	folio_unlock(folio);
 
 	submit_bio_wait(&bio);
 	__end_swap_bio_write(&bio);
-- 
2.25.1

[PATCH v2 7/9] mm/page_io: use a folio in swap_writepage_bdev_async()

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Saves one implicit call to compound_head().

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/page_io.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 0c96ea9dd258..e28395331bb0 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -352,6 +352,7 @@ static void swap_writepage_bdev_async(struct page *page,
 		struct writeback_control *wbc, struct swap_info_struct *sis)
 {
 	struct bio *bio;
+	struct folio *folio = page_folio(page);
 
 	bio = bio_alloc(sis->bdev, 1,
 			REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
@@ -362,8 +363,8 @@ static void swap_writepage_bdev_async(struct page *page,
 
 	bio_associate_blkg_from_page(bio, page);
 	count_swpout_vm_event(page);
-	set_page_writeback(page);
-	unlock_page(page);
+	folio_start_writeback(folio);
+	folio_unlock(folio);
 	submit_bio(bio);
 }
 
-- 
2.25.1

[PATCH v2 8/9] mm/page_io: convert count_swpout_vm_event() to take in a folio

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Convert count_swpout_vm_event() to take in a folio. We can remove five
implicit calls to compound_head() by taking in a folio.

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
---
 mm/page_io.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index e28395331bb0..fa8caf1c05d8 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -205,13 +205,13 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 	return 0;
 }
 
-static inline void count_swpout_vm_event(struct page *page)
+static inline void count_swpout_vm_event(struct folio *folio)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	if (unlikely(PageTransHuge(page)))
+	if (unlikely(folio_test_pmd_mappable(folio)))
 		count_vm_event(THP_SWPOUT);
 #endif
-	count_vm_events(PSWPOUT, thp_nr_pages(page));
+	count_vm_events(PSWPOUT, folio_nr_pages(folio));
 }
 
 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
@@ -280,7 +280,7 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
 		}
 	} else {
 		for (p = 0; p < sio->pages; p++)
-			count_swpout_vm_event(sio->bvec[p].bv_page);
+			count_swpout_vm_event(page_folio(sio->bvec[p].bv_page));
 	}
 
 	for (p = 0; p < sio->pages; p++)
@@ -339,7 +339,7 @@ static void swap_writepage_bdev_sync(struct page *page,
 	__bio_add_page(&bio, page, thp_size(page), 0);
 
 	bio_associate_blkg_from_page(&bio, page);
-	count_swpout_vm_event(page);
+	count_swpout_vm_event(folio);
 
 	folio_start_writeback(folio);
 	folio_unlock(folio);
@@ -362,7 +362,7 @@ static void swap_writepage_bdev_async(struct page *page,
 	__bio_add_page(bio, page, thp_size(page), 0);
 
 	bio_associate_blkg_from_page(bio, page);
-	count_swpout_vm_event(page);
+	count_swpout_vm_event(folio);
 	folio_start_writeback(folio);
 	folio_unlock(folio);
 	submit_bio(bio);
-- 
2.25.1

[PATCH v2 9/9] mm/page_io: convert bio_associate_blkg_from_page() to take in a folio

[Peng Zhang]

From: ZhangPeng <zhangpeng362@huawei.com>

Convert bio_associate_blkg_from_page() to take in a folio. We can remove
two implicit calls to compound_head() by taking in a folio.

Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/page_io.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index fa8caf1c05d8..dcb58888dd36 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -215,12 +215,12 @@ static inline void count_swpout_vm_event(struct folio *folio)
 }
 
 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
-static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
+static void bio_associate_blkg_from_page(struct bio *bio, struct folio *folio)
 {
 	struct cgroup_subsys_state *css;
 	struct mem_cgroup *memcg;
 
-	memcg = page_memcg(page);
+	memcg = folio_memcg(folio);
 	if (!memcg)
 		return;
 
@@ -230,7 +230,7 @@ static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
 	rcu_read_unlock();
 }
 #else
-#define bio_associate_blkg_from_page(bio, page)		do { } while (0)
+#define bio_associate_blkg_from_page(bio, folio)		do { } while (0)
 #endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */
 
 struct swap_iocb {
@@ -338,7 +338,7 @@ static void swap_writepage_bdev_sync(struct page *page,
 	bio.bi_iter.bi_sector = swap_page_sector(page);
 	__bio_add_page(&bio, page, thp_size(page), 0);
 
-	bio_associate_blkg_from_page(&bio, page);
+	bio_associate_blkg_from_page(&bio, folio);
 	count_swpout_vm_event(folio);
 
 	folio_start_writeback(folio);
@@ -361,7 +361,7 @@ static void swap_writepage_bdev_async(struct page *page,
 	bio->bi_end_io = end_swap_bio_write;
 	__bio_add_page(bio, page, thp_size(page), 0);
 
-	bio_associate_blkg_from_page(bio, page);
+	bio_associate_blkg_from_page(bio, folio);
 	count_swpout_vm_event(folio);
 	folio_start_writeback(folio);
 	folio_unlock(folio);
-- 
2.25.1

Re: [PATCH v2 3/9] mm/page_io: convert bio_first_page_all() to bio_first_folio_all()

[Matthew Wilcox]

On Wed, Jul 19, 2023 at 05:58:42PM +0800, Peng Zhang wrote:
> From: ZhangPeng <zhangpeng362@huawei.com>
> 
> Convert bio_first_page_all() to bio_first_folio_all() to return a
> folio, which makes it easier to use.

This wasn't what I was suggesting.  Indeed, this may introduce bugs.
I was suggesting adding bio_first_folio_all() so that it can be used
by code that knows this is what it wants.

> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
> ---
>  Documentation/block/biovecs.rst  | 2 +-
>  drivers/block/drbd/drbd_bitmap.c | 2 +-
>  fs/f2fs/data.c                   | 2 +-
>  include/linux/bio.h              | 4 ++--
>  kernel/power/swap.c              | 2 +-
>  mm/page_io.c                     | 4 ++--
>  6 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/block/biovecs.rst b/Documentation/block/biovecs.rst
> index ddb867e0185b..258f6faed333 100644
> --- a/Documentation/block/biovecs.rst
> +++ b/Documentation/block/biovecs.rst
> @@ -133,7 +133,7 @@ Usage of helpers:
>  	bio_for_each_segment_all()
>  	bio_for_each_bvec_all()
>  	bio_first_bvec_all()
> -	bio_first_page_all()
> +	bio_first_folio_all()
>  	bio_last_bvec_all()
>  
>  * The following helpers iterate over single-page segment. The passed 'struct
> diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
> index 85ca000a0564..ce1a07ba85ff 100644
> --- a/drivers/block/drbd/drbd_bitmap.c
> +++ b/drivers/block/drbd/drbd_bitmap.c
> @@ -939,7 +939,7 @@ static void drbd_bm_endio(struct bio *bio)
>  	struct drbd_bm_aio_ctx *ctx = bio->bi_private;
>  	struct drbd_device *device = ctx->device;
>  	struct drbd_bitmap *b = device->bitmap;
> -	unsigned int idx = bm_page_to_idx(bio_first_page_all(bio));
> +	unsigned int idx = bm_page_to_idx(&bio_first_folio_all(bio)->page);
>  
>  	if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
>  	    !bm_test_page_unchanged(b->bm_pages[idx]))
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 5882afe71d82..6706858de984 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -288,7 +288,7 @@ static void f2fs_post_read_work(struct work_struct *work)
>  
>  static void f2fs_read_end_io(struct bio *bio)
>  {
> -	struct f2fs_sb_info *sbi = F2FS_P_SB(bio_first_page_all(bio));
> +	struct f2fs_sb_info *sbi = F2FS_P_SB(&bio_first_folio_all(bio)->page);
>  	struct bio_post_read_ctx *ctx;
>  	bool intask = in_task();
>  
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index c4f5b5228105..7d2979d24530 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -248,9 +248,9 @@ static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
>  	return bio->bi_io_vec;
>  }
>  
> -static inline struct page *bio_first_page_all(struct bio *bio)
> +static inline struct folio *bio_first_folio_all(struct bio *bio)
>  {
> -	return bio_first_bvec_all(bio)->bv_page;
> +	return page_folio(bio_first_bvec_all(bio)->bv_page);
>  }
>  
>  static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> index f6ebcd00c410..2796ce48ca4b 100644
> --- a/kernel/power/swap.c
> +++ b/kernel/power/swap.c
> @@ -247,7 +247,7 @@ static void hib_finish_batch(struct hib_bio_batch *hb)
>  static void hib_end_io(struct bio *bio)
>  {
>  	struct hib_bio_batch *hb = bio->bi_private;
> -	struct page *page = bio_first_page_all(bio);
> +	struct page *page = &bio_first_folio_all(bio)->page;
>  
>  	if (bio->bi_status) {
>  		pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
> diff --git a/mm/page_io.c b/mm/page_io.c
> index 5ddb5d9c5013..e21d570c873d 100644
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -29,7 +29,7 @@
>  
>  static void __end_swap_bio_write(struct bio *bio)
>  {
> -	struct page *page = bio_first_page_all(bio);
> +	struct page *page = &bio_first_folio_all(bio)->page;
>  
>  	if (bio->bi_status) {
>  		/*
> @@ -57,7 +57,7 @@ static void end_swap_bio_write(struct bio *bio)
>  
>  static void __end_swap_bio_read(struct bio *bio)
>  {
> -	struct page *page = bio_first_page_all(bio);
> +	struct page *page = &bio_first_folio_all(bio)->page;
>  
>  	if (bio->bi_status) {
>  		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
> -- 
> 2.25.1
> 

Re: [PATCH v2 8/9] mm/page_io: convert count_swpout_vm_event() to take in a folio

[Matthew Wilcox]

On Wed, Jul 19, 2023 at 05:58:47PM +0800, Peng Zhang wrote:
> -static inline void count_swpout_vm_event(struct page *page)
> +static inline void count_swpout_vm_event(struct folio *folio)
>  {
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -	if (unlikely(PageTransHuge(page)))
> +	if (unlikely(folio_test_pmd_mappable(folio)))
>  		count_vm_event(THP_SWPOUT);
>  #endif

As I said in my earlier response, you don't need the ifdefs.  Check
the definition of folio_test_pmd_mappable.

Re: [PATCH v2 3/9] mm/page_io: convert bio_first_page_all() to bio_first_folio_all()

[Christoph Hellwig]

On Wed, Jul 19, 2023 at 03:17:34PM +0100, Matthew Wilcox wrote:
> On Wed, Jul 19, 2023 at 05:58:42PM +0800, Peng Zhang wrote:
> > From: ZhangPeng <zhangpeng362@huawei.com>
> > 
> > Convert bio_first_page_all() to bio_first_folio_all() to return a
> > folio, which makes it easier to use.
> 
> This wasn't what I was suggesting.  Indeed, this may introduce bugs.
> I was suggesting adding bio_first_folio_all() so that it can be used
> by code that knows this is what it wants.

To add another opinion:  I'd really like to see bio_first_page_all
go away.  The right way to iterate over the pages is an iterator.
If we really want to micro-opimize not setting up an iteator because
we know we have exactly one page/folio just stash it into bi_private.

Re: [PATCH v2 3/9] mm/page_io: convert bio_first_page_all() to bio_first_folio_all()

[zhangpeng (AS)]

On 2023/7/19 22:17, Matthew Wilcox wrote:

> On Wed, Jul 19, 2023 at 05:58:42PM +0800, Peng Zhang wrote:
>> From: ZhangPeng<zhangpeng362@huawei.com>
>>
>> Convert bio_first_page_all() to bio_first_folio_all() to return a
>> folio, which makes it easier to use.
> This wasn't what I was suggesting.  Indeed, this may introduce bugs.
> I was suggesting adding bio_first_folio_all() so that it can be used
> by code that knows this is what it wants.

Sorry for my misunderstanding, I will fix it in the next version.

>> Suggested-by: Matthew Wilcox (Oracle)<willy@infradead.org>
>> Signed-off-by: ZhangPeng<zhangpeng362@huawei.com>
>> ---
>>   Documentation/block/biovecs.rst  | 2 +-
>>   drivers/block/drbd/drbd_bitmap.c | 2 +-
>>   fs/f2fs/data.c                   | 2 +-
>>   include/linux/bio.h              | 4 ++--
>>   kernel/power/swap.c              | 2 +-
>>   mm/page_io.c                     | 4 ++--
>>   6 files changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/block/biovecs.rst b/Documentation/block/biovecs.rst
>> index ddb867e0185b..258f6faed333 100644
>> --- a/Documentation/block/biovecs.rst
>> +++ b/Documentation/block/biovecs.rst
>> @@ -133,7 +133,7 @@ Usage of helpers:
>>   	bio_for_each_segment_all()
>>   	bio_for_each_bvec_all()
>>   	bio_first_bvec_all()
>> -	bio_first_page_all()
>> +	bio_first_folio_all()
>>   	bio_last_bvec_all()
>>   
>>   * The following helpers iterate over single-page segment. The passed 'struct
>> diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
>> index 85ca000a0564..ce1a07ba85ff 100644
>> --- a/drivers/block/drbd/drbd_bitmap.c
>> +++ b/drivers/block/drbd/drbd_bitmap.c
>> @@ -939,7 +939,7 @@ static void drbd_bm_endio(struct bio *bio)
>>   	struct drbd_bm_aio_ctx *ctx = bio->bi_private;
>>   	struct drbd_device *device = ctx->device;
>>   	struct drbd_bitmap *b = device->bitmap;
>> -	unsigned int idx = bm_page_to_idx(bio_first_page_all(bio));
>> +	unsigned int idx = bm_page_to_idx(&bio_first_folio_all(bio)->page);
>>   
>>   	if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
>>   	    !bm_test_page_unchanged(b->bm_pages[idx]))
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 5882afe71d82..6706858de984 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -288,7 +288,7 @@ static void f2fs_post_read_work(struct work_struct *work)
>>   
>>   static void f2fs_read_end_io(struct bio *bio)
>>   {
>> -	struct f2fs_sb_info *sbi = F2FS_P_SB(bio_first_page_all(bio));
>> +	struct f2fs_sb_info *sbi = F2FS_P_SB(&bio_first_folio_all(bio)->page);
>>   	struct bio_post_read_ctx *ctx;
>>   	bool intask = in_task();
>>   
>> diff --git a/include/linux/bio.h b/include/linux/bio.h
>> index c4f5b5228105..7d2979d24530 100644
>> --- a/include/linux/bio.h
>> +++ b/include/linux/bio.h
>> @@ -248,9 +248,9 @@ static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
>>   	return bio->bi_io_vec;
>>   }
>>   
>> -static inline struct page *bio_first_page_all(struct bio *bio)
>> +static inline struct folio *bio_first_folio_all(struct bio *bio)
>>   {
>> -	return bio_first_bvec_all(bio)->bv_page;
>> +	return page_folio(bio_first_bvec_all(bio)->bv_page);
>>   }
>>   
>>   static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
>> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
>> index f6ebcd00c410..2796ce48ca4b 100644
>> --- a/kernel/power/swap.c
>> +++ b/kernel/power/swap.c
>> @@ -247,7 +247,7 @@ static void hib_finish_batch(struct hib_bio_batch *hb)
>>   static void hib_end_io(struct bio *bio)
>>   {
>>   	struct hib_bio_batch *hb = bio->bi_private;
>> -	struct page *page = bio_first_page_all(bio);
>> +	struct page *page = &bio_first_folio_all(bio)->page;
>>   
>>   	if (bio->bi_status) {
>>   		pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
>> diff --git a/mm/page_io.c b/mm/page_io.c
>> index 5ddb5d9c5013..e21d570c873d 100644
>> --- a/mm/page_io.c
>> +++ b/mm/page_io.c
>> @@ -29,7 +29,7 @@
>>   
>>   static void __end_swap_bio_write(struct bio *bio)
>>   {
>> -	struct page *page = bio_first_page_all(bio);
>> +	struct page *page = &bio_first_folio_all(bio)->page;
>>   
>>   	if (bio->bi_status) {
>>   		/*
>> @@ -57,7 +57,7 @@ static void end_swap_bio_write(struct bio *bio)
>>   
>>   static void __end_swap_bio_read(struct bio *bio)
>>   {
>> -	struct page *page = bio_first_page_all(bio);
>> +	struct page *page = &bio_first_folio_all(bio)->page;
>>   
>>   	if (bio->bi_status) {
>>   		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
>> -- 
>> 2.25.1
>>
-- 
Best Regards,
Peng

Re: [PATCH v2 8/9] mm/page_io: convert count_swpout_vm_event() to take in a folio

[zhangpeng (AS)]

On 2023/7/19 22:24, Matthew Wilcox wrote:

> On Wed, Jul 19, 2023 at 05:58:47PM +0800, Peng Zhang wrote:
>> -static inline void count_swpout_vm_event(struct page *page)
>> +static inline void count_swpout_vm_event(struct folio *folio)
>>   {
>>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> -	if (unlikely(PageTransHuge(page)))
>> +	if (unlikely(folio_test_pmd_mappable(folio)))
>>   		count_vm_event(THP_SWPOUT);
>>   #endif
> As I said in my earlier response, you don't need the ifdefs.  Check
> the definition of folio_test_pmd_mappable.

Sorry I forgot to delete the ifdefs. I'll fix it in a v3.
Thanks.

-- 
Best Regards,
Peng