On Mon, Jun 07, 2021 at 06:35:39PM +0800, Coly Li wrote: > + /* Limitation for valid replace key size and cache_bio bvecs number */ > + size_limit = min_t(unsigned int, bio_max_segs(UINT_MAX) * PAGE_SECTORS, > + (1 << KEY_SIZE_BITS) - 1); bio_max_segs kaps the argument to BIO_MAX_VECS, so you might as well directly write BIO_MAX_VECS. Can you explain the PAGE_SECTORS here a bit more? Does this code path use discontiguous per-sector allocations? Preferably in a comment. > + s->insert_bio_sectors = min3(size_limit, sectors, bio_sectors(bio)); Also I don't really understand the units involved here. s->insert_bio_sectors, sectors, and bio_sectors is in unit of 512 byte sectors. > - miss = bio_next_split(bio, sectors, GFP_NOIO, &s->d->bio_split); > + miss = bio_next_split(bio, s->insert_bio_sectors, GFP_NOIO, &s->d->bio_split); Overly long line.