| Message ID | 20190321231037.25104-15-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 the controller supports SGLs we can take another short cut for single > segment request, given that we can always map those without another > indirection structure, and thus don't need to create a scatterlist > structure. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/nvme/host/pci.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > index 47fc4d653961..38869f59c296 100644 > --- a/drivers/nvme/host/pci.c > +++ b/drivers/nvme/host/pci.c > @@ -819,6 +819,23 @@ static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev, > return 0; > } > > +static blk_status_t nvme_setup_sgl_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); > + > + 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.sgl.addr = cpu_to_le64(iod->first_dma); > + cmnd->dptr.sgl.length = cpu_to_le32(iod->dma_len); > + cmnd->dptr.sgl.type = NVME_SGL_FMT_DATA_DESC << 4; > + return 0; > +} > + > static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, > struct nvme_command *cmnd) > { > @@ -836,6 +853,11 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, > if (bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2) > return nvme_setup_prp_simple(dev, req, > &cmnd->rw, &bv); > + > + if (iod->nvmeq->qid && > + dev->ctrl.sgls & ((1 << 0) | (1 << 1))) > + return nvme_setup_sgl_simple(dev, req, > + &cmnd->rw, &bv); > } > } > > Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
On Thu, Mar 21, 2019 at 04:10:36PM -0700, Christoph Hellwig wrote: > If the controller supports SGLs we can take another short cut for single > segment request, given that we can always map those without another > indirection structure, and thus don't need to create a scatterlist > structure. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/nvme/host/pci.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > index 47fc4d653961..38869f59c296 100644 > --- a/drivers/nvme/host/pci.c > +++ b/drivers/nvme/host/pci.c > @@ -819,6 +819,23 @@ static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev, > return 0; > } > > +static blk_status_t nvme_setup_sgl_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); > + > + 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.sgl.addr = cpu_to_le64(iod->first_dma); > + cmnd->dptr.sgl.length = cpu_to_le32(iod->dma_len); > + cmnd->dptr.sgl.type = NVME_SGL_FMT_DATA_DESC << 4; > + return 0; > +} > + > static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, > struct nvme_command *cmnd) > { > @@ -836,6 +853,11 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, > if (bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2) > return nvme_setup_prp_simple(dev, req, > &cmnd->rw, &bv); > + > + if (iod->nvmeq->qid && > + dev->ctrl.sgls & ((1 << 0) | (1 << 1))) > + return nvme_setup_sgl_simple(dev, req, > + &cmnd->rw, &bv); > } > } > > -- > 2.20.1 > Hi Christoph, nvme_setup_sgl_simple does not set the PSDT field, so bypassing nvme_pci_setup_sgls causing controllers to assume PRP. Adding `cmnd->flags = NVME_CMD_SGL_METABUF` in nvme_setup_sgl_simple fixes the issue.
On Tue, Apr 30, 2019 at 04:17:22PM +0200, Klaus Birkelund wrote: > nvme_setup_sgl_simple does not set the PSDT field, so bypassing > nvme_pci_setup_sgls causing controllers to assume PRP. > > Adding `cmnd->flags = NVME_CMD_SGL_METABUF` in nvme_setup_sgl_simple > fixes the issue. Indeed. Can you send the patch?
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 47fc4d653961..38869f59c296 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -819,6 +819,23 @@ static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev, return 0; } +static blk_status_t nvme_setup_sgl_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); + + 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.sgl.addr = cpu_to_le64(iod->first_dma); + cmnd->dptr.sgl.length = cpu_to_le32(iod->dma_len); + cmnd->dptr.sgl.type = NVME_SGL_FMT_DATA_DESC << 4; + return 0; +} + static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, struct nvme_command *cmnd) { @@ -836,6 +853,11 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, if (bv.bv_offset + bv.bv_len <= dev->ctrl.page_size * 2) return nvme_setup_prp_simple(dev, req, &cmnd->rw, &bv); + + if (iod->nvmeq->qid && + dev->ctrl.sgls & ((1 << 0) | (1 << 1))) + return nvme_setup_sgl_simple(dev, req, + &cmnd->rw, &bv); } }
If the controller supports SGLs we can take another short cut for single segment request, given that we can always map those without another indirection structure, and thus don't need to create a scatterlist structure. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/nvme/host/pci.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)