[PATCH v5] mm/page_io: rename swap_iocb fields for clarity

[PATCH v5] mm/page_io: rename swap_iocb fields for clarity

[David Carlier]

swap_iocb->pages tracks the number of bvec entries (folios), not base
pages. Rename the array from bvec to bvecs and the counter from pages
to nr_bvecs to accurately reflect their purpose.

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: David Carlier <devnexen@gmail.com>
---
 mm/page_io.c | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 1389cd57ca88..18ff6f559cbd 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -326,8 +326,8 @@ static void bio_associate_blkg_from_page(struct bio *bio, struct folio *folio)
 
 struct swap_iocb {
 	struct kiocb		iocb;
-	struct bio_vec		bvec[SWAP_CLUSTER_MAX];
-	int			pages;
+	struct bio_vec		bvecs[SWAP_CLUSTER_MAX];
+	int			nr_bvecs;
 	int			len;
 };
 static mempool_t *sio_pool;
@@ -348,7 +348,7 @@ int sio_pool_init(void)
 static void sio_write_complete(struct kiocb *iocb, long ret)
 {
 	struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
-	struct page *page = sio->bvec[0].bv_page;
+	struct page *page = sio->bvecs[0].bv_page;
 	int p;
 
 	if (ret != sio->len) {
@@ -362,15 +362,15 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
 		 */
 		pr_err_ratelimited("Write error %ld on dio swapfile (%llu)\n",
 				   ret, swap_dev_pos(page_swap_entry(page)));
-		for (p = 0; p < sio->pages; p++) {
-			page = sio->bvec[p].bv_page;
+		for (p = 0; p < sio->nr_bvecs; p++) {
+			page = sio->bvecs[p].bv_page;
 			set_page_dirty(page);
 			ClearPageReclaim(page);
 		}
 	}
 
-	for (p = 0; p < sio->pages; p++)
-		end_page_writeback(sio->bvec[p].bv_page);
+	for (p = 0; p < sio->nr_bvecs; p++)
+		end_page_writeback(sio->bvecs[p].bv_page);
 
 	mempool_free(sio, sio_pool);
 }
@@ -397,13 +397,13 @@ static void swap_writepage_fs(struct folio *folio, struct swap_iocb **swap_plug)
 		init_sync_kiocb(&sio->iocb, swap_file);
 		sio->iocb.ki_complete = sio_write_complete;
 		sio->iocb.ki_pos = pos;
-		sio->pages = 0;
+		sio->nr_bvecs = 0;
 		sio->len = 0;
 	}
-	bvec_set_folio(&sio->bvec[sio->pages], folio, folio_size(folio), 0);
+	bvec_set_folio(&sio->bvecs[sio->nr_bvecs], folio, folio_size(folio), 0);
 	sio->len += folio_size(folio);
-	sio->pages += 1;
-	if (sio->pages == ARRAY_SIZE(sio->bvec) || !swap_plug) {
+	sio->nr_bvecs += 1;
+	if (sio->nr_bvecs == ARRAY_SIZE(sio->bvecs) || !swap_plug) {
 		swap_write_unplug(sio);
 		sio = NULL;
 	}
@@ -477,7 +477,7 @@ void swap_write_unplug(struct swap_iocb *sio)
 	struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
 	int ret;
 
-	iov_iter_bvec(&from, ITER_SOURCE, sio->bvec, sio->pages, sio->len);
+	iov_iter_bvec(&from, ITER_SOURCE, sio->bvecs, sio->nr_bvecs, sio->len);
 	ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
 	if (ret != -EIOCBQUEUED)
 		sio_write_complete(&sio->iocb, ret);
@@ -489,8 +489,8 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
 	int p;
 
 	if (ret == sio->len) {
-		for (p = 0; p < sio->pages; p++) {
-			struct folio *folio = page_folio(sio->bvec[p].bv_page);
+		for (p = 0; p < sio->nr_bvecs; p++) {
+			struct folio *folio = page_folio(sio->bvecs[p].bv_page);
 
 			count_mthp_stat(folio_order(folio), MTHP_STAT_SWPIN);
 			count_memcg_folio_events(folio, PSWPIN, folio_nr_pages(folio));
@@ -499,8 +499,8 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
 		}
 		count_vm_events(PSWPIN, sio->len >> PAGE_SHIFT);
 	} else {
-		for (p = 0; p < sio->pages; p++) {
-			struct folio *folio = page_folio(sio->bvec[p].bv_page);
+		for (p = 0; p < sio->nr_bvecs; p++) {
+			struct folio *folio = page_folio(sio->bvecs[p].bv_page);
 
 			folio_unlock(folio);
 		}
@@ -559,13 +559,13 @@ static void swap_read_folio_fs(struct folio *folio, struct swap_iocb **plug)
 		init_sync_kiocb(&sio->iocb, sis->swap_file);
 		sio->iocb.ki_pos = pos;
 		sio->iocb.ki_complete = sio_read_complete;
-		sio->pages = 0;
+		sio->nr_bvecs = 0;
 		sio->len = 0;
 	}
-	bvec_set_folio(&sio->bvec[sio->pages], folio, folio_size(folio), 0);
+	bvec_set_folio(&sio->bvecs[sio->nr_bvecs], folio, folio_size(folio), 0);
 	sio->len += folio_size(folio);
-	sio->pages += 1;
-	if (sio->pages == ARRAY_SIZE(sio->bvec) || !plug) {
+	sio->nr_bvecs += 1;
+	if (sio->nr_bvecs == ARRAY_SIZE(sio->bvecs) || !plug) {
 		swap_read_unplug(sio);
 		sio = NULL;
 	}
@@ -666,7 +666,7 @@ void __swap_read_unplug(struct swap_iocb *sio)
 	struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
 	int ret;
 
-	iov_iter_bvec(&from, ITER_DEST, sio->bvec, sio->pages, sio->len);
+	iov_iter_bvec(&from, ITER_DEST, sio->bvecs, sio->nr_bvecs, sio->len);
 	ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
 	if (ret != -EIOCBQUEUED)
 		sio_read_complete(&sio->iocb, ret);
-- 
2.53.0

Re: [PATCH v5] mm/page_io: rename swap_iocb fields for clarity

[David Hildenbrand (Arm)]

On 4/2/26 09:26, David Carlier wrote:
> swap_iocb->pages tracks the number of bvec entries (folios), not base
> pages. Rename the array from bvec to bvecs and the counter from pages
> to nr_bvecs to accurately reflect their purpose.
> 
> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: David Carlier <devnexen@gmail.com>
> ---

Thanks!

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v5] mm/page_io: rename swap_iocb fields for clarity

[Chris Li]

On Thu, Apr 2, 2026 at 12:27 AM David Carlier <devnexen@gmail.com> wrote:
>
> swap_iocb->pages tracks the number of bvec entries (folios), not base
> pages. Rename the array from bvec to bvecs and the counter from pages
> to nr_bvecs to accurately reflect their purpose.
>
> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: David Carlier <devnexen@gmail.com>
Thank you.

Acked-by: Chris Li <chrisl@kernel.org>

Chris