diff options
| author | Christoph Hellwig <hch@lst.de> | 2020-04-14 09:42:22 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-04-22 10:47:06 -0600 |
| commit | 89de1504d53b59b12bfff227328ee3e63dd3a112 (patch) | |
| tree | 2205ed1010c146887a329bdf953b74b04afedd87 /block | |
| parent | e64a0e16928415648d53d721b3d6fc3635eddf92 (diff) | |
| download | linux-89de1504d53b59b12bfff227328ee3e63dd3a112.tar.bz2 | |
block: provide a blk_rq_map_sg variant that returns the last element
To be able to move some of the special purpose hacks in blk_rq_map_sg
into the callers we need a variant that returns the last mapped
S/G list element to the caller. Add that variant as __blk_rq_map_sg
and make blk_rq_map_sg a trivial inline wrapper around it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-merge.c | 25 |
1 files changed, 12 insertions, 13 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 99c9759f3a8a..ee618cdb141e 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -519,24 +519,23 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, * map a request to scatterlist, return number of sg entries setup. Caller * must make sure sg can hold rq->nr_phys_segments entries */ -int blk_rq_map_sg(struct request_queue *q, struct request *rq, - struct scatterlist *sglist) +int __blk_rq_map_sg(struct request_queue *q, struct request *rq, + struct scatterlist *sglist, struct scatterlist **last_sg) { - struct scatterlist *sg = NULL; int nsegs = 0; if (rq->rq_flags & RQF_SPECIAL_PAYLOAD) - nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, &sg); + nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, last_sg); else if (rq->bio && bio_op(rq->bio) == REQ_OP_WRITE_SAME) - nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, &sg); + nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, last_sg); else if (rq->bio) - nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); + nsegs = __blk_bios_map_sg(q, rq->bio, sglist, last_sg); if (blk_rq_bytes(rq) && (blk_rq_bytes(rq) & q->dma_pad_mask)) { unsigned int pad_len = (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; - sg->length += pad_len; + (*last_sg)->length += pad_len; rq->extra_len += pad_len; } @@ -544,9 +543,9 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, if (op_is_write(req_op(rq))) memset(q->dma_drain_buffer, 0, q->dma_drain_size); - sg_unmark_end(sg); - sg = sg_next(sg); - sg_set_page(sg, virt_to_page(q->dma_drain_buffer), + sg_unmark_end(*last_sg); + *last_sg = sg_next(*last_sg); + sg_set_page(*last_sg, virt_to_page(q->dma_drain_buffer), q->dma_drain_size, ((unsigned long)q->dma_drain_buffer) & (PAGE_SIZE - 1)); @@ -554,8 +553,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, rq->extra_len += q->dma_drain_size; } - if (sg) - sg_mark_end(sg); + if (*last_sg) + sg_mark_end(*last_sg); /* * Something must have been wrong if the figured number of @@ -565,7 +564,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, return nsegs; } -EXPORT_SYMBOL(blk_rq_map_sg); +EXPORT_SYMBOL(__blk_rq_map_sg); static inline int ll_new_hw_segment(struct request *req, struct bio *bio, unsigned int nr_phys_segs) |