block: turn bio_kmalloc into a simple kmalloc wrapper

Remove the magic autofree semantics and require the callers to explicitly
call bio_init to initialize the bio.

This allows bio_free to catch accidental bio_put calls on bio_init()ed
bios as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Coly Li <colyli@suse.de>
Acked-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20220406061228.410163-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 7c85458..5d1aa5b 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -152,23 +152,25 @@ static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)
 
 	src_bio->bi_status = enc_bio->bi_status;
 
-	bio_put(enc_bio);
+	bio_uninit(enc_bio);
+	kfree(enc_bio);
 	bio_endio(src_bio);
 }
 
 static struct bio *blk_crypto_fallback_clone_bio(struct bio *bio_src)
 {
+	unsigned int nr_segs = bio_segments(bio_src);
 	struct bvec_iter iter;
 	struct bio_vec bv;
 	struct bio *bio;
 
-	bio = bio_kmalloc(GFP_NOIO, bio_segments(bio_src));
+	bio = bio_kmalloc(nr_segs, GFP_NOIO);
 	if (!bio)
 		return NULL;
-	bio->bi_bdev		= bio_src->bi_bdev;
+	bio_init(bio, bio_src->bi_bdev, bio->bi_inline_vecs, nr_segs,
+		 bio_src->bi_opf);
 	if (bio_flagged(bio_src, BIO_REMAPPED))
 		bio_set_flag(bio, BIO_REMAPPED);
-	bio->bi_opf		= bio_src->bi_opf;
 	bio->bi_ioprio		= bio_src->bi_ioprio;
 	bio->bi_iter.bi_sector	= bio_src->bi_iter.bi_sector;
 	bio->bi_iter.bi_size	= bio_src->bi_iter.bi_size;
@@ -363,8 +365,8 @@ static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
 	blk_crypto_put_keyslot(slot);
 out_put_enc_bio:
 	if (enc_bio)
-		bio_put(enc_bio);
-
+		bio_uninit(enc_bio);
+	kfree(enc_bio);
 	return ret;
 }