bcache: fix wrong bdev parameter when calling bio_alloc_clone() in do_bio_hook()

Commit abfc426 ("block: pass a block_device to bio_clone_fast")
calls the modified bio_alloc_clone() in bcache code as:
	bio_init_clone(bio->bi_bdev, bio, orig_bio, GFP_NOIO);

But the first parameter is wrong, where bio->bi_bdev should be
orig_bio->bi_bdev. The wrong bi_bdev panics the kernel when submitting
cache bio.

This patch fixes the wrong bdev parameter usage and avoid the panic.

Fixes: abfc426 ("block: pass a block_device to bio_clone_fast")
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220419160425.4148-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Coly Li

drivers/md/bcache/request.c

@@ -685,7 +685,7 @@ static void do_bio_hook(struct search *s,
 {
 	struct bio *bio = &s->bio.bio;
 
-	bio_init_clone(bio->bi_bdev, bio, orig_bio, GFP_NOIO);
+	bio_init_clone(orig_bio->bi_bdev, bio, orig_bio, GFP_NOIO);
 	/*
 	 * bi_end_io can be set separately somewhere else, e.g. the
 	 * variants in,