Hi, Now the whole IO stack is capable of handling multi-page bvec, and it has been enabled in the normal FS IO path. However, it isn't done for passthrough IO. Without enabling multi-bvec for passthough IO, we won't go ahead for optimizing related IO paths, such as bvec merging, bio_add_pc_page simplification. This patch enables multi-page bvec for passthrough IO. Turns out bio_add_pc_page() is simpliefied a lot, especially the physical segment number of passthrough bio is always same with bio.bi_vcnt. Also the bvec merging inside bio is killed. blktests(block/029) is added for covering passthough IO path, and this patchset does pass the new block/029 test. https://marc.info/?l=linux-block&m=155175063417139&w=2 V2: - add new patch of 'block: avoid to break XEN by multi-page bvec' - add one new patch to cleanup bio_add_pc_page() - add another two new patches for cleanup of mapping bvec to sg - most of others are patch style changes Ming Lei (10): block: pass page to xen_biovec_phys_mergeable block: avoid to break XEN by multi-page bvec block: don't merge adjacent bvecs to one segment in bio blk_queue_split block: cleanup bio_add_pc_page block: check if page is mergeable in one helper block: put the same page when adding it to bio block: enable multi-page bvec for passthrough IO block: remove argument of 'request_queue' from __blk_bvec_map_sg block: reuse __blk_bvec_map_sg() for mapping page sized bvec block: don't check if adjacent bvecs in one bio can be mergeable block/bio.c | 134 ++++++++++++++++++++++++++++--------------------- block/blk-merge.c | 106 +++++++++++++++++++------------------- block/blk.h | 2 +- drivers/xen/biomerge.c | 5 +- include/linux/bio.h | 3 ++ include/xen/xen.h | 2 +- 6 files changed, 135 insertions(+), 117 deletions(-) Cc: ris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx Cc: Omar Sandoval <osandov@xxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> -- 2.9.5
