bcache: clean up do_btree_node_write a bit

Use a variable containing the buffer address instead of the to be
removed integer iterator from bio_for_each_segment_all.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed