[PATCH v3 21/26] block: Add bio_for_each_segment_all()

__bio_for_each_segment() iterates bvecs from the specified index instead of bio->bv_idx. Currently, the only usage is to walk all the bvecs after the bio has been advanced by specifying 0 index. For immutable bvecs, we need to split these apart; bio_for_each_segment() is going to have a

[PATCH v3 21/26] block: Add bio_for_each_segment_all()

__bio_for_each_segment() iterates bvecs from the specified index instead of bio-bv_idx. Currently, the only usage is to walk all the bvecs after the bio has been advanced by specifying 0 index. For immutable bvecs, we need to split these apart; bio_for_each_segment() is going to have a different