| Message ID | abe693fad3abb0adfc0cf9ca5b3d287fdb0f2d5b.1464144791.git.baolin.wang@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, May 25, 2016 at 2:12 PM, Baolin Wang <baolin.wang@linaro.org> wrote: > In dm-crypt, it need to map one bio to scatterlist for improving the > hardware engine encryption efficiency. Thus this patch introduces the > blk_bio_map_sg() function to map one bio with scatterlists. > > Signed-off-by: Baolin Wang <baolin.wang@linaro.org> > --- > block/blk-merge.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > include/linux/blkdev.h | 3 +++ > 2 files changed, 48 insertions(+) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 2613531..9b92af4 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -417,6 +417,51 @@ single_segment: > } > > /* > + * map a bio to scatterlist, return number of sg entries setup. > + */ > +int blk_bio_map_sg(struct request_queue *q, struct bio *bio, > + struct scatterlist *sglist, > + struct scatterlist **sg) > +{ > + struct bio_vec bvec, bvprv = { NULL }; > + struct bvec_iter iter; > + int nsegs, cluster; > + > + nsegs = 0; > + cluster = blk_queue_cluster(q); > + > + if (bio->bi_rw & REQ_DISCARD) { > + /* > + * This is a hack - drivers should be neither modifying the > + * biovec, nor relying on bi_vcnt - but because of > + * blk_add_request_payload(), a discard bio may or may not have > + * a payload we need to set up here (thank you Christoph) and > + * bi_vcnt is really the only way of telling if we need to. > + */ > + > + if (bio->bi_vcnt) > + goto single_segment; > + > + return 0; > + } > + > + if (bio->bi_rw & REQ_WRITE_SAME) { > +single_segment: > + *sg = sglist; > + bvec = bio_iovec(bio); > + sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); > + return 1; > + } > + > + bio_for_each_segment(bvec, bio, iter) > + __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, > + &nsegs, &cluster); > + > + return nsegs; > +} > +EXPORT_SYMBOL(blk_bio_map_sg); You can use __blk_bios_map_sg() to implement blk_bio_map_sg(), then code duplication may be avoided. > + > +/* > * map a request to scatterlist, return number of sg entries setup. Caller > * must make sure sg can hold rq->nr_phys_segments entries > */ > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 1fd8fdf..e5de4f8 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -1013,6 +1013,9 @@ extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fu > extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); > > extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); > +extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio, > + struct scatterlist *sglist, > + struct scatterlist **sg); > extern void blk_dump_rq_flags(struct request *, char *); > extern long nr_blockdev_pages(void); > > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 25 May 2016 at 16:52, Ming Lei <ming.lei@canonical.com> wrote: >> /* >> + * map a bio to scatterlist, return number of sg entries setup. >> + */ >> +int blk_bio_map_sg(struct request_queue *q, struct bio *bio, >> + struct scatterlist *sglist, >> + struct scatterlist **sg) >> +{ >> + struct bio_vec bvec, bvprv = { NULL }; >> + struct bvec_iter iter; >> + int nsegs, cluster; >> + >> + nsegs = 0; >> + cluster = blk_queue_cluster(q); >> + >> + if (bio->bi_rw & REQ_DISCARD) { >> + /* >> + * This is a hack - drivers should be neither modifying the >> + * biovec, nor relying on bi_vcnt - but because of >> + * blk_add_request_payload(), a discard bio may or may not have >> + * a payload we need to set up here (thank you Christoph) and >> + * bi_vcnt is really the only way of telling if we need to. >> + */ >> + >> + if (bio->bi_vcnt) >> + goto single_segment; >> + >> + return 0; >> + } >> + >> + if (bio->bi_rw & REQ_WRITE_SAME) { >> +single_segment: >> + *sg = sglist; >> + bvec = bio_iovec(bio); >> + sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); >> + return 1; >> + } >> + >> + bio_for_each_segment(bvec, bio, iter) >> + __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, >> + &nsegs, &cluster); >> + >> + return nsegs; >> +} >> +EXPORT_SYMBOL(blk_bio_map_sg); > > You can use __blk_bios_map_sg() to implement blk_bio_map_sg(), > then code duplication may be avoided. OK. I'll re-factor the code to map one bio. > >> + >> +/* >> * map a request to scatterlist, return number of sg entries setup. Caller >> * must make sure sg can hold rq->nr_phys_segments entries >> */ >> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >> index 1fd8fdf..e5de4f8 100644 >> --- a/include/linux/blkdev.h >> +++ b/include/linux/blkdev.h >> @@ -1013,6 +1013,9 @@ extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fu >> extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); >> >> extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); >> +extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio, >> + struct scatterlist *sglist, >> + struct scatterlist **sg); >> extern void blk_dump_rq_flags(struct request *, char *); >> extern long nr_blockdev_pages(void); >> >> -- >> 1.7.9.5 >>
diff --git a/block/blk-merge.c b/block/blk-merge.c index 2613531..9b92af4 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -417,6 +417,51 @@ single_segment: } /* + * map a bio to scatterlist, return number of sg entries setup. + */ +int blk_bio_map_sg(struct request_queue *q, struct bio *bio, + struct scatterlist *sglist, + struct scatterlist **sg) +{ + struct bio_vec bvec, bvprv = { NULL }; + struct bvec_iter iter; + int nsegs, cluster; + + nsegs = 0; + cluster = blk_queue_cluster(q); + + if (bio->bi_rw & REQ_DISCARD) { + /* + * This is a hack - drivers should be neither modifying the + * biovec, nor relying on bi_vcnt - but because of + * blk_add_request_payload(), a discard bio may or may not have + * a payload we need to set up here (thank you Christoph) and + * bi_vcnt is really the only way of telling if we need to. + */ + + if (bio->bi_vcnt) + goto single_segment; + + return 0; + } + + if (bio->bi_rw & REQ_WRITE_SAME) { +single_segment: + *sg = sglist; + bvec = bio_iovec(bio); + sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); + return 1; + } + + bio_for_each_segment(bvec, bio, iter) + __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, + &nsegs, &cluster); + + return nsegs; +} +EXPORT_SYMBOL(blk_bio_map_sg); + +/* * map a request to scatterlist, return number of sg entries setup. Caller * must make sure sg can hold rq->nr_phys_segments entries */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1fd8fdf..e5de4f8 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1013,6 +1013,9 @@ extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fu extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); +extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio, + struct scatterlist *sglist, + struct scatterlist **sg); extern void blk_dump_rq_flags(struct request *, char *); extern long nr_blockdev_pages(void);
In dm-crypt, it need to map one bio to scatterlist for improving the hardware engine encryption efficiency. Thus this patch introduces the blk_bio_map_sg() function to map one bio with scatterlists. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> --- block/blk-merge.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/blkdev.h | 3 +++ 2 files changed, 48 insertions(+)