Hello, Asias. On Mon, Jun 18, 2012 at 02:53:08PM +0800, Asias He wrote: > Split the mapping code in blk_rq_map_sg() to a helper > __blk_segment_map_sg(), so that other mapping function, e.g. > blk_bio_map_sg(), can share the code. > > Cc: Jens Axboe <[email protected]> > Cc: Tejun Heo <[email protected]> > Cc: Shaohua Li <[email protected]> > Cc: [email protected] > Suggested-by: Tejun Heo <[email protected]> > Suggested-by: Jens Axboe <[email protected]> > Signed-off-by: Asias He <[email protected]> > --- > block/blk-merge.c | 80 > ++++++++++++++++++++++++++++++----------------------- > 1 file changed, 45 insertions(+), 35 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 160035f..576b68e 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -110,6 +110,49 @@ static int blk_phys_contig_segment(struct request_queue > *q, struct bio *bio, > return 0; > } > > +static void > +__blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, > + struct scatterlist *sglist, struct bio_vec **bvprv, > + struct scatterlist **sg, int *nsegs, int *cluster) > +{ > + > + int nbytes = bvec->bv_len; > + > + if (*bvprv && *cluster) { > + if ((*sg)->length + nbytes > queue_max_segment_size(q)) > + goto new_segment; > + > + if (!BIOVEC_PHYS_MERGEABLE(*bvprv, bvec)) > + goto new_segment; > + if (!BIOVEC_SEG_BOUNDARY(q, *bvprv, bvec)) > + goto new_segment; > + > + (*sg)->length += nbytes; > + } else { > +new_segment: > + if (!*sg) > + *sg = sglist; > + else { > + /* > + * If the driver previously mapped a shorter > + * list, we could see a termination bit > + * prematurely unless it fully inits the sg > + * table on each mapping. We KNOW that there > + * must be more entries here or the driver > + * would be buggy, so force clear the > + * termination bit to avoid doing a full > + * sg_init_table() in drivers for each command. > + */ > + (*sg)->page_link &= ~0x02; > + *sg = sg_next(*sg); > + } > + > + sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); > + (*nsegs)++; > + } > + *bvprv = bvec; > +}
I *hope* this is a bit prettier. e.g. Do we really need to pass in @sglist and keep using "goto new_segment"? Thanks. -- tejun _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
