nvme: add helper nvme_map_len()

The helper returns the number of bytes that need to be mapped
using PRPs/SGL entries.

Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index f846da4eb3380fb743fa449010e1e12e2e3e2a7d..6376cd71cc9fc1f635161a0e451661842dc44846 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -173,6 +173,14 @@ static inline u64 nvme_block_nr(struct nvme_ns *ns, sector_t sector)
        return (sector >> (ns->lba_shift - 9));
 }
 
+static inline unsigned nvme_map_len(struct request *rq)
+{
+       if (rq->cmd_flags & REQ_DISCARD)
+               return sizeof(struct nvme_dsm_range);
+       else
+               return blk_rq_bytes(rq);
+}
+
 static inline void nvme_setup_flush(struct nvme_ns *ns,
                struct nvme_command *cmnd)
 {

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 154194e33c316930210c3c61c9cf829cf6868cb4..d23ede73537dcbf35c417691e246c1c8615c3bf6 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -334,16 +334,11 @@ static __le64 **iod_list(struct request *req)
        return (__le64 **)(iod->sg + req->nr_phys_segments);
 }
 
-static int nvme_init_iod(struct request *rq, struct nvme_dev *dev)
+static int nvme_init_iod(struct request *rq, unsigned size,
+               struct nvme_dev *dev)
 {
        struct nvme_iod *iod = blk_mq_rq_to_pdu(rq);
        int nseg = rq->nr_phys_segments;
-       unsigned size;
-
-       if (rq->cmd_flags & REQ_DISCARD)
-               size = sizeof(struct nvme_dsm_range);
-       else
-               size = blk_rq_bytes(rq);
 
        if (nseg > NVME_INT_PAGES || size > NVME_INT_BYTES(dev)) {
                iod->sg = kmalloc(nvme_iod_alloc_size(dev, size, nseg), GFP_ATOMIC);
@@ -637,6 +632,7 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
        struct nvme_dev *dev = nvmeq->dev;
        struct request *req = bd->rq;
        struct nvme_command cmnd;
+       unsigned map_len;
        int ret = BLK_MQ_RQ_QUEUE_OK;
 
        /*
@@ -652,7 +648,8 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
                }
        }
 
-       ret = nvme_init_iod(req, dev);
+       map_len = nvme_map_len(req);
+       ret = nvme_init_iod(req, map_len, dev);
        if (ret)
                return ret;