On Mon, Apr 08, 2019 at 12:46:37PM +0200, Christoph Hellwig wrote: > The offset in scatterlists is allowed to be larger than the page size, > so don't go to great length to avoid that case and simplify the > arithmetics. > > Signed-off-by: Christoph Hellwig <[email protected]> > --- > block/blk-merge.c | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 8f96d683b577..52dbdd089fdf 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -467,26 +467,17 @@ static unsigned blk_bvec_map_sg(struct request_queue *q, > struct scatterlist **sg) > { > unsigned nbytes = bvec->bv_len; > - unsigned nsegs = 0, total = 0, offset = 0; > + unsigned nsegs = 0, total = 0; > > while (nbytes > 0) { > - unsigned seg_size; > - struct page *pg; > - unsigned idx; > + unsigned offset = bvec->bv_offset + total; > + unsigned len = min(get_max_segment_size(q, offset), nbytes); > > *sg = blk_next_sg(sg, sglist); > + sg_set_page(*sg, bvec->bv_page, len, offset); > > - seg_size = get_max_segment_size(q, bvec->bv_offset + total); > - seg_size = min(nbytes, seg_size); > - > - offset = (total + bvec->bv_offset) % PAGE_SIZE; > - idx = (total + bvec->bv_offset) / PAGE_SIZE; > - pg = bvec_nth_page(bvec->bv_page, idx); > - > - sg_set_page(*sg, pg, seg_size, offset); > - > - total += seg_size; > - nbytes -= seg_size; > + total += len; > + nbytes -= len; > nsegs++; > }
Nice cleanup & simplification: Reviewed-by: Ming Lei <[email protected]> Thanks, Ming
