if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID)))
blk_recount_segments(q, nxt);
if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) ||
if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID)))
blk_recount_segments(q, nxt);
if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) ||