| Message ID | 20190321231037.25104-14-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/15] block: add a req_bvec helper | expand |
On 3/21/19 4:12 PM, Christoph Hellwig wrote: > If a request is single segment and fits into one or two PRP entries we > do not have to create a scatterlist for it, but can just map the bio_vec > directly. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/nvme/host/pci.c | 45 ++++++++++++++++++++++++++++++++++++----- > 1 file changed, 40 insertions(+), 5 deletions(-) > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > index c6047935e825..47fc4d653961 100644 > --- a/drivers/nvme/host/pci.c > +++ b/drivers/nvme/host/pci.c > @@ -221,6 +221,7 @@ struct nvme_iod { > int npages; /* In the PRP list. 0 means small pool in use */ > int nents; /* Used in scatterlist */ > dma_addr_t first_dma; > + unsigned int dma_len; /* length of single DMA segment mapping */ > dma_addr_t meta_dma; > struct scatterlist *sg; > }; > @@ -576,13 +577,18 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req) > dma_addr_t dma_addr = iod->first_dma, next_dma_addr; > int i; > > - if (iod->nents) { > - /* P2PDMA requests do not need to be unmapped */ > - if (!is_pci_p2pdma_page(sg_page(iod->sg))) > - dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir); > - > + if (iod->dma_len) { > + dma_unmap_page(dev->dev, dma_addr, iod->dma_len, dma_dir); > + return; > } > > + WARN_ON_ONCE(!iod->nents); > + > + /* P2PDMA requests do not need to be unmapped */ > + if (!is_pci_p2pdma_page(sg_page(iod->sg))) > + dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req)); > + > + > if (iod->npages == 0) > dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0], > dma_addr); > @@ -795,6 +801,24 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev, > return BLK_STS_OK; > } > > +static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev, > + struct request *req, struct nvme_rw_command *cmnd, > + struct bio_vec *bv) > +{ > + struct nvme_iod *iod = blk_mq_rq_to_pdu(req); > + unsigned int first_prp_len = dev->ctrl.page_size - bv->bv_offset; > + > + iod->first_dma = dma_map_bvec(dev->dev, bv, rq_dma_dir(req), 0); > + if (dma_mapping_error(dev->dev, iod->first_dma)) > + return BLK_STS_RESOURCE; > + iod->dma_len = bv->bv_len; > + > + cmnd->dptr.prp1 = cpu_to_le64(iod->first_dma); > + if (bv->bv_len > first_prp_len) > + cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma + first_prp_len); > + return 0; > +} > + > static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, > struct nvme_command *cmnd) > { > @@ -805,6 +829,17 @@ 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_nr_phys_segments(req) == 1) { > + struct bio_vec bv = req_bvec(req); > + > + if (!is_pci_p2pdma_page(bv.bv_page)) { > + if (bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2) > + return nvme_setup_prp_simple(dev, req, > + &cmnd->rw, &bv); > + } > + } > + > + iod->dma_len = 0; > iod->sg = mempool_alloc(dev->iod_mempool, GFP_ATOMIC); > if (!iod->sg) > return BLK_STS_RESOURCE; > Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index c6047935e825..47fc4d653961 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -221,6 +221,7 @@ struct nvme_iod { int npages; /* In the PRP list. 0 means small pool in use */ int nents; /* Used in scatterlist */ dma_addr_t first_dma; + unsigned int dma_len; /* length of single DMA segment mapping */ dma_addr_t meta_dma; struct scatterlist *sg; }; @@ -576,13 +577,18 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req) dma_addr_t dma_addr = iod->first_dma, next_dma_addr; int i; - if (iod->nents) { - /* P2PDMA requests do not need to be unmapped */ - if (!is_pci_p2pdma_page(sg_page(iod->sg))) - dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir); - + if (iod->dma_len) { + dma_unmap_page(dev->dev, dma_addr, iod->dma_len, dma_dir); + return; } + WARN_ON_ONCE(!iod->nents); + + /* P2PDMA requests do not need to be unmapped */ + if (!is_pci_p2pdma_page(sg_page(iod->sg))) + dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req)); + + if (iod->npages == 0) dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0], dma_addr); @@ -795,6 +801,24 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev, return BLK_STS_OK; } +static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev, + struct request *req, struct nvme_rw_command *cmnd, + struct bio_vec *bv) +{ + struct nvme_iod *iod = blk_mq_rq_to_pdu(req); + unsigned int first_prp_len = dev->ctrl.page_size - bv->bv_offset; + + iod->first_dma = dma_map_bvec(dev->dev, bv, rq_dma_dir(req), 0); + if (dma_mapping_error(dev->dev, iod->first_dma)) + return BLK_STS_RESOURCE; + iod->dma_len = bv->bv_len; + + cmnd->dptr.prp1 = cpu_to_le64(iod->first_dma); + if (bv->bv_len > first_prp_len) + cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma + first_prp_len); + return 0; +} + static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, struct nvme_command *cmnd) { @@ -805,6 +829,17 @@ 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_nr_phys_segments(req) == 1) { + struct bio_vec bv = req_bvec(req); + + if (!is_pci_p2pdma_page(bv.bv_page)) { + if (bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2) + return nvme_setup_prp_simple(dev, req, + &cmnd->rw, &bv); + } + } + + iod->dma_len = 0; iod->sg = mempool_alloc(dev->iod_mempool, GFP_ATOMIC); if (!iod->sg) return BLK_STS_RESOURCE;
If a request is single segment and fits into one or two PRP entries we do not have to create a scatterlist for it, but can just map the bio_vec directly. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/nvme/host/pci.c | 45 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 40 insertions(+), 5 deletions(-)