[v2,07/19] md: raid5: use __bio_add_page to add single page to new bio

Commit Message

Johannes Thumshirn March 30, 2023, 10:43 a.m. UTC

The raid5-ppl submission code uses bio_add_page() to add a page to a
newly created bio. bio_add_page() can fail, but the return value is never
checked. For adding consecutive pages, the return is actually checked and
a new bio is allocated if adding the page fails.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Signed-off-by: Johannes Thumshirn <[e-mail]>
Reviewed-by: Damien Le Moal <[e-mail]>
---
 drivers/md/raid5-ppl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Song Liu March 31, 2023, 5:47 p.m. UTC | #1

On Thu, Mar 30, 2023 at 3:44 AM Johannes Thumshirn
<[e-mail]> wrote:
>
> The raid5-ppl submission code uses bio_add_page() to add a page to a
> newly created bio. bio_add_page() can fail, but the return value is never
> checked. For adding consecutive pages, the return is actually checked and
> a new bio is allocated if adding the page fails.
>
> Use __bio_add_page() as adding a single page to a newly created bio is
> guaranteed to succeed.
>
> This brings us a step closer to marking bio_add_page() as __must_check.
>
> Signed-off-by: Johannes Thumshirn <[e-mail]>
> Reviewed-by: Damien Le Moal <[e-mail]>

Acked-by: Song Liu <[e-mail]>

Patch

diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c
index e495939bb3e0..eaea57aee602 100644
--- a/drivers/md/raid5-ppl.c
+++ b/drivers/md/raid5-ppl.c
@@ -465,7 +465,7 @@  static void ppl_submit_iounit(struct ppl_io_unit *io)
 
 	bio->bi_end_io = ppl_log_endio;
 	bio->bi_iter.bi_sector = log->next_io_sector;
-	bio_add_page(bio, io->header_page, PAGE_SIZE, 0);
+	__bio_add_page(bio, io->header_page, PAGE_SIZE, 0);
 
 	pr_debug("%s: log->current_io_sector: %llu\n", __func__,
 	    (unsigned long long)log->next_io_sector);
@@ -496,7 +496,7 @@  static void ppl_submit_iounit(struct ppl_io_unit *io)
 					       prev->bi_opf, GFP_NOIO,
 					       &ppl_conf->bs);
 			bio->bi_iter.bi_sector = bio_end_sector(prev);
-			bio_add_page(bio, sh->ppl_page, PAGE_SIZE, 0);
+			__bio_add_page(bio, sh->ppl_page, PAGE_SIZE, 0);
 
 			bio_chain(bio, prev);
 			ppl_submit_iounit_bio(io, prev);