* 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;
}
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));
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
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)
return max_t(unsigned short, rq->nr_phys_segments, 1);
}
-extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
+int __blk_rq_map_sg(struct request_queue *q, struct request *rq,
+ struct scatterlist *sglist, struct scatterlist **last_sg);
+static inline int blk_rq_map_sg(struct request_queue *q, struct request *rq,
+ struct scatterlist *sglist)
+{
+ struct scatterlist *last_sg = NULL;
+
+ return __blk_rq_map_sg(q, rq, sglist, &last_sg);
+}
extern void blk_dump_rq_flags(struct request *, char *);
extern long nr_blockdev_pages(void);