block: pass a minsize argument to bio_iov_iter_bounce

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);
@@ -1344,16 +1345,16 @@ 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,
-		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;
 
@@ -1382,26 +1383,28 @@ 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);
 }
 
 /**
  * bio_iov_iter_bounce - bounce buffer data from an iter into a bio
  * @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
  * consistency.  Allocates folios to back the bounce buffer, and for writes
  * 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)

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);

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,