From 99d3ebf523bbb0e5668f60db890f944055f5e07a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 May 2026 07:01:47 +0200 Subject: [PATCH 1/2] block: pass a minsize argument to bio_iov_iter_bounce When bouncing for block size > PAGE_SIZE file systems that require file system block size alignment (e.g. zoned XFS), the bio needs to be big enough to fit an entire block. Signed-off-by: Christoph Hellwig --- block/bio.c | 23 +++++++++++++---------- fs/iomap/direct-io.c | 2 +- include/linux/bio.h | 3 ++- 3 files changed, 16 insertions(+), 12 deletions(-) diff --git a/block/bio.c b/block/bio.c index b8972dba68a09..f3e5d8bea08cd 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1279,11 +1279,12 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, return bio_iov_iter_align_down(bio, iter, len_align_mask); } -static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size) +static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size, + size_t minsize) { struct folio *folio; - while (*size > PAGE_SIZE) { + while (*size > minsize) { folio = folio_alloc(gfp | __GFP_NORETRY, get_order(*size)); if (folio) return folio; @@ -1307,7 +1308,7 @@ static void bio_free_folios(struct bio *bio) } static int bio_iov_iter_bounce_write(struct bio *bio, struct iov_iter *iter, - size_t maxlen) + size_t maxlen, size_t minsize) { size_t total_len = min(maxlen, iov_iter_count(iter)); @@ -1322,13 +1323,13 @@ static int bio_iov_iter_bounce_write(struct bio *bio, struct iov_iter *iter, size_t this_len = min(total_len, SZ_1M); struct folio *folio; - if (this_len > PAGE_SIZE * 2) + if (this_len > minsize * 2) this_len = rounddown_pow_of_two(this_len); if (bio->bi_iter.bi_size > BIO_MAX_SIZE - this_len) break; - folio = folio_alloc_greedy(GFP_KERNEL, &this_len); + folio = folio_alloc_greedy(GFP_KERNEL, &this_len, minsize); if (!folio) break; bio_add_folio_nofail(bio, folio, this_len, 0); @@ -1348,12 +1349,12 @@ static int bio_iov_iter_bounce_write(struct bio *bio, struct iov_iter *iter, } static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter, - size_t maxlen) + size_t maxlen, size_t minsize) { size_t len = min3(iov_iter_count(iter), maxlen, SZ_1M); struct folio *folio; - folio = folio_alloc_greedy(GFP_KERNEL, &len); + folio = folio_alloc_greedy(GFP_KERNEL, &len, minsize); if (!folio) return -ENOMEM; @@ -1390,6 +1391,7 @@ static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter, * @bio: bio to send * @iter: iter to read from / write into * @maxlen: maximum size to bounce + * @minsize: minimum folio allocation size * * Helper for direct I/O implementations that need to bounce buffer because * we need to checksum the data or perform other operations that require @@ -1397,11 +1399,12 @@ static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter, * copies the data into it. Needs to be paired with bio_iov_iter_unbounce() * called on completion. */ -int bio_iov_iter_bounce(struct bio *bio, struct iov_iter *iter, size_t maxlen) +int bio_iov_iter_bounce(struct bio *bio, struct iov_iter *iter, size_t maxlen, + size_t minsize) { if (op_is_write(bio_op(bio))) - return bio_iov_iter_bounce_write(bio, iter, maxlen); - return bio_iov_iter_bounce_read(bio, iter, maxlen); + return bio_iov_iter_bounce_write(bio, iter, maxlen, minsize); + return bio_iov_iter_bounce_read(bio, iter, maxlen, minsize); } static void bvec_unpin(struct bio_vec *bv, bool mark_dirty) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index b0a6549b38487..b36ee619cdcdd 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -355,7 +355,7 @@ static ssize_t iomap_dio_bio_iter_one(struct iomap_iter *iter, if (dio->flags & IOMAP_DIO_BOUNCE) ret = bio_iov_iter_bounce(bio, dio->submit.iter, - iomap_max_bio_size(&iter->iomap)); + iomap_max_bio_size(&iter->iomap), alignment); else ret = bio_iov_iter_get_pages(bio, dio->submit.iter, alignment - 1); diff --git a/include/linux/bio.h b/include/linux/bio.h index 97d747320b35b..dc17780d6c1e3 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -475,7 +475,8 @@ void __bio_release_pages(struct bio *bio, bool mark_dirty); extern void bio_set_pages_dirty(struct bio *bio); extern void bio_check_pages_dirty(struct bio *bio); -int bio_iov_iter_bounce(struct bio *bio, struct iov_iter *iter, size_t maxlen); +int bio_iov_iter_bounce(struct bio *bio, struct iov_iter *iter, size_t maxlen, + size_t minsize); void bio_iov_iter_unbounce(struct bio *bio, bool is_error, bool mark_dirty); extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter, From 5ec470911504660b19068b9f2488d1f91a0e4146 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 May 2026 07:01:48 +0200 Subject: [PATCH 2/2] block: align down bounces bios Just like for the extract user pages path, we need to align down the size to the supported boundary. Signed-off-by: Christoph Hellwig --- block/bio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/bio.c b/block/bio.c index f3e5d8bea08cd..5f10900b3f42a 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1345,7 +1345,7 @@ static int bio_iov_iter_bounce_write(struct bio *bio, struct iov_iter *iter, if (!bio->bi_iter.bi_size) return -ENOMEM; - return 0; + return bio_iov_iter_align_down(bio, iter, minsize - 1); } static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter, @@ -1383,7 +1383,7 @@ static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter, bvec_set_folio(&bio->bi_io_vec[0], folio, bio->bi_iter.bi_size, 0); if (iov_iter_extract_will_pin(iter)) bio_set_flag(bio, BIO_PAGE_PINNED); - return 0; + return bio_iov_iter_align_down(bio, iter, minsize - 1); } /**