1 files changed, 39 insertions, 25 deletions

diff --git a/block/bio.c b/block/bio.c
index f2a5f4d0a967..6a2f6fc3413e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -555,6 +555,14 @@ struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,
 		bio = bio_alloc_percpu_cache(bs);
 	} else {
 		opf &= ~REQ_ALLOC_CACHE;
+	}
+
+	/*
+	 * For a bioset without a percpu cache, or when the percpu cache was
+	 * empty, try a slab allocation with optimistic GFP_ flags before
+	 * falling back to the mempool.
+	 */
+	if (!bio) {
 		p = kmem_cache_alloc(bs->bio_slab, gfp);
 		if (p)
 			bio = p + bs->front_pad;
@@ -1191,7 +1199,7 @@ void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter)
  * for the next iteration.
  */
 static int bio_iov_iter_align_down(struct bio *bio, struct iov_iter *iter,
-			    unsigned len_align_mask)
+				   struct bio_vec *bv, unsigned len_align_mask)
 {
 	size_t nbytes = bio->bi_iter.bi_size & len_align_mask;
 
@@ -1200,23 +1208,16 @@ static int bio_iov_iter_align_down(struct bio *bio, struct iov_iter *iter,
 
 	iov_iter_revert(iter, nbytes);
 	bio->bi_iter.bi_size -= nbytes;
-	do {
-		struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
-
-		if (nbytes < bv->bv_len) {
-			bv->bv_len -= nbytes;
-			break;
-		}
-
+	while (nbytes >= bv->bv_len) {
 		if (bio_flagged(bio, BIO_PAGE_PINNED))
 			unpin_user_page(bv->bv_page);
 
-		bio->bi_vcnt--;
+		if (!--bio->bi_vcnt)
+			return -EFAULT;
 		nbytes -= bv->bv_len;
-	} while (nbytes);
-
-	if (!bio->bi_vcnt)
-		return -EFAULT;
+		bv--;
+	}
+	bv->bv_len -= nbytes;
 	return 0;
 }
 
@@ -1276,7 +1277,8 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter,
 
 	if (is_pci_p2pdma_page(bio->bi_io_vec->bv_page))
 		bio->bi_opf |= REQ_NOMERGE;
-	return bio_iov_iter_align_down(bio, iter, len_align_mask);
+	return bio_iov_iter_align_down(bio, iter,
+			&bio->bi_io_vec[bio->bi_vcnt - 1], len_align_mask);
 }
 
 static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size,
@@ -1285,7 +1287,8 @@ static struct folio *folio_alloc_greedy(gfp_t gfp, size_t *size,
 	struct folio *folio;
 
 	while (*size > minsize) {
-		folio = folio_alloc(gfp | __GFP_NORETRY, get_order(*size));
+		folio = folio_alloc(gfp | __GFP_NORETRY | __GFP_NOWARN,
+				    get_order(*size));
 		if (folio)
 			return folio;
 		*size = rounddown_pow_of_two(*size - 1);
@@ -1302,7 +1305,7 @@ static void bio_free_folios(struct bio *bio)
 	bio_for_each_bvec_all(bv, bio, i) {
 		struct folio *folio = bvec_folio(bv);
 
-		if (!is_zero_folio(folio))
+		if (!is_zero_folio(folio) && !is_huge_zero_folio(folio))
 			folio_put(folio);
 	}
 }
@@ -1360,7 +1363,8 @@ static int bio_iov_iter_bounce_write(struct bio *bio, struct iov_iter *iter,
 
 	if (!bio->bi_iter.bi_size)
 		return -ENOMEM;
-	return bio_iov_iter_align_down(bio, iter, minsize - 1);
+	return bio_iov_iter_align_down(bio, iter,
+			&bio->bi_io_vec[bio->bi_vcnt - 1], minsize - 1);
 }
 
 static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter,
@@ -1368,21 +1372,18 @@ static int bio_iov_iter_bounce_read(struct bio *bio, struct iov_iter *iter,
 {
 	size_t len = min3(iov_iter_count(iter), maxlen, SZ_1M);
 	struct folio *folio;
+	ssize_t ret;
 
 	folio = folio_alloc_greedy(GFP_KERNEL, &len, minsize);
 	if (!folio)
 		return -ENOMEM;
 
 	do {
-		ssize_t ret;
-
 		ret = iov_iter_extract_bvecs(iter, bio->bi_io_vec + 1, len,
 				&bio->bi_vcnt, bio->bi_max_vecs - 1, 0);
 		if (ret <= 0) {
-			if (!bio->bi_vcnt) {
-				folio_put(folio);
-				return ret;
-			}
+			if (!bio->bi_vcnt)
+				goto out_folio_put;
 			break;
 		}
 		len -= ret;
@@ -1398,7 +1399,20 @@ 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 bio_iov_iter_align_down(bio, iter, minsize - 1);
+
+	/* The first vec stores the bounce buffer, so do not subtract 1 here. */
+	ret = bio_iov_iter_align_down(bio, iter,
+			&bio->bi_io_vec[bio->bi_vcnt], minsize - 1);
+	if (ret)
+		goto out_folio_put;
+
+	/* Update the bounc buffer bv_len to the aligned down size. */
+	bio->bi_io_vec[0].bv_len = bio->bi_iter.bi_size;
+	return 0;
+
+out_folio_put:
+	folio_put(folio);
+	return ret;
 }
 
 /**