nvme-pci: remove nvme_init_iod

nvme_init_iod should really be split into two parts: initialize a few
general iod fields, which can easily be done at the beginning of
nvme_queue_rq, and allocating the scatterlist if needed, which logically
belongs into nvme_map_data with the code making use of it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0cba927224b429e9403c6c88ab841ebeab37b62d..2102a107e09bfd99ae4f44da66c2540cc9f5264f 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -208,10 +208,10 @@ struct nvme_queue {
 };
 
 /*
- * The nvme_iod describes the data in an I/O, including the list of PRP
- * entries.  You can't see it in this data structure because C doesn't let
- * me express that.  Use nvme_init_iod to ensure there's enough space
- * allocated to store the PRP list.
+ * The nvme_iod describes the data in an I/O.
+ *
+ * The sg pointer contains the list of PRP/SGL chunk allocations in addition
+ * to the actual struct scatterlist.
  */
 struct nvme_iod {
        struct nvme_request req;
@@ -583,29 +583,6 @@ static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
        return true;
 }
 
-static blk_status_t nvme_init_iod(struct request *rq, struct nvme_dev *dev)
-{
-       struct nvme_iod *iod = blk_mq_rq_to_pdu(rq);
-       int nseg = blk_rq_nr_phys_segments(rq);
-       unsigned int size = blk_rq_payload_bytes(rq);
-
-       iod->use_sgl = nvme_pci_use_sgls(dev, rq);
-
-       if (nseg > NVME_INT_PAGES || size > NVME_INT_BYTES(dev)) {
-               iod->sg = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
-               if (!iod->sg)
-                       return BLK_STS_RESOURCE;
-       } else {
-               iod->sg = iod->inline_sg;
-       }
-
-       iod->aborted = 0;
-       iod->npages = -1;
-       iod->nents = 0;
-
-       return BLK_STS_OK;
-}
-
 static void nvme_free_iod(struct nvme_dev *dev, struct request *req)
 {
        struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
@@ -837,6 +814,17 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
        blk_status_t ret = BLK_STS_IOERR;
        int nr_mapped;
 
+       if (blk_rq_payload_bytes(req) > NVME_INT_BYTES(dev) ||
+           blk_rq_nr_phys_segments(req) > NVME_INT_PAGES) {
+               iod->sg = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
+               if (!iod->sg)
+                       return BLK_STS_RESOURCE;
+       } else {
+               iod->sg = iod->inline_sg;
+       }
+
+       iod->use_sgl = nvme_pci_use_sgls(dev, req);
+
        sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
        iod->nents = blk_rq_map_sg(q, req, iod->sg);
        if (!iod->nents)
@@ -881,6 +869,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 out_unmap:
        dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir);
 out:
+       nvme_free_iod(dev, req);
        return ret;
 }
 
@@ -913,9 +902,14 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
        struct nvme_queue *nvmeq = hctx->driver_data;
        struct nvme_dev *dev = nvmeq->dev;
        struct request *req = bd->rq;
+       struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
        struct nvme_command cmnd;
        blk_status_t ret;
 
+       iod->aborted = 0;
+       iod->npages = -1;
+       iod->nents = 0;
+
        /*
         * We should not need to do this, but we're still using this to
         * ensure we can drain requests on a dying queue.
@@ -927,21 +921,15 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
        if (ret)
                return ret;
 
-       ret = nvme_init_iod(req, dev);
-       if (ret)
-               goto out_free_cmd;
-
        if (blk_rq_nr_phys_segments(req)) {
                ret = nvme_map_data(dev, req, &cmnd);
                if (ret)
-                       goto out_cleanup_iod;
+                       goto out_free_cmd;
        }
 
        blk_mq_start_request(req);
        nvme_submit_cmd(nvmeq, &cmnd, bd->last);
        return BLK_STS_OK;
-out_cleanup_iod:
-       nvme_free_iod(dev, req);
 out_free_cmd:
        nvme_cleanup_cmd(req);
        return ret;