On 3/21/19 4:11 PM, Christoph Hellwig wrote:
> 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@xxxxxx>
> ---
> drivers/nvme/host/pci.c | 56 ++++++++++++++++-------------------------
> 1 file changed, 22 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index bf0d71fe243e..3f06e942fb47 100644
> --- 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;
> +
Maybe add an inline helper for above default IOD initialization ?
> /*
> * 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;
>
Otherwise, looks good.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
