Instead of filling in a bio_list and submitting the bios in the only
caller, do that in scrub_assemble_read_bios.  This removes the
need to pass the bio_list, and also makes it clear that the extra
bio_list cleanup in the caller is entirely pointless.  Rename the
function to scrub_read_bios to make it clear that the bios are not
only assembled.
Reviewed-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>