[PATCH v8 10/13] nvme-pci: convert to using dma_map_sgtable()

Logan Gunthorpe
2022-07-08T16:51:29Z

The dma_map operations now support P2PDMA pages directly. So remove
the calls to pci_p2pdma_[un]map_sg_attrs() and replace them with calls
to dma_map_sgtable().

dma_map_sgtable() returns more complete error codes than dma_map_sg()
and allows differentiating EREMOTEIO errors in case an unsupported
P2PDMA transfer is requested. When this happens, return BLK_STS_TARGET
so the request isn't retried.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
drivers/nvme/host/pci.c | 69 +++++++++++++++++------------------------
1 file changed, 29 insertions(+), 40 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0f556e954ffc..696434658e53 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -230,11 +230,10 @@ struct nvme_iod {
bool use_sgl;
int aborted;
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;
+ struct sg_table sgt;
};

static inline unsigned int nvme_dbbuf_size(struct nvme_dev *dev)
@@ -524,7 +523,7 @@ static void nvme_commit_rqs(struct blk_mq_hw_ctx *hctx)
static void **nvme_pci_iod_list(struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- return (void **)(iod->sg + blk_rq_nr_phys_segments(req));
+ return (void **)(iod->sgt.sgl + blk_rq_nr_phys_segments(req));
}

static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
@@ -576,17 +575,6 @@ static void nvme_free_sgls(struct nvme_dev *dev, struct request *req)
}
}

-static void nvme_unmap_sg(struct nvme_dev *dev, struct request *req)
-{
- struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-
- if (is_pci_p2pdma_page(sg_page(iod->sg)))
- pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
- rq_dma_dir(req));
- else
- dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
-}
-
static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
@@ -597,9 +585,10 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
return;
}

- WARN_ON_ONCE(!iod->nents);
+ WARN_ON_ONCE(!iod->sgt.nents);
+
+ dma_unmap_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req), 0);

- nvme_unmap_sg(dev, req);
if (iod->npages == 0)
dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
iod->first_dma);
@@ -607,7 +596,7 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
nvme_free_sgls(dev, req);
else
nvme_free_prps(dev, req);
- mempool_free(iod->sg, dev->iod_mempool);
+ mempool_free(iod->sgt.sgl, dev->iod_mempool);
}

static void nvme_print_sgl(struct scatterlist *sgl, int nents)
@@ -630,7 +619,7 @@ static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
struct dma_pool *pool;
int length = blk_rq_payload_bytes(req);
- struct scatterlist *sg = iod->sg;
+ struct scatterlist *sg = iod->sgt.sgl;
int dma_len = sg_dma_len(sg);
u64 dma_addr = sg_dma_address(sg);
int offset = dma_addr & (NVME_CTRL_PAGE_SIZE - 1);
@@ -703,16 +692,16 @@ static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
dma_len = sg_dma_len(sg);
}
done:
- cmnd->dptr.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+ cmnd->dptr.prp1 = cpu_to_le64(sg_dma_address(iod->sgt.sgl));
cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma);
return BLK_STS_OK;
free_prps:
nvme_free_prps(dev, req);
return BLK_STS_RESOURCE;
bad_sgl:
- WARN(DO_ONCE(nvme_print_sgl, iod->sg, iod->nents),
+ WARN(DO_ONCE(nvme_print_sgl, iod->sgt.sgl, iod->sgt.nents),
"Invalid SGL for payload:%d nents:%d\n",
- blk_rq_payload_bytes(req), iod->nents);
+ blk_rq_payload_bytes(req), iod->sgt.nents);
return BLK_STS_IOERR;
}

@@ -738,12 +727,13 @@ static void nvme_pci_sgl_set_seg(struct nvme_sgl_desc *sge,
}

static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
- struct request *req, struct nvme_rw_command *cmd, int entries)
+ struct request *req, struct nvme_rw_command *cmd)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
struct dma_pool *pool;
struct nvme_sgl_desc *sg_list;
- struct scatterlist *sg = iod->sg;
+ struct scatterlist *sg = iod->sgt.sgl;
+ unsigned int entries = iod->sgt.nents;
dma_addr_t sgl_dma;
int i = 0;

@@ -841,7 +831,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
blk_status_t ret = BLK_STS_RESOURCE;
- int nr_mapped;
+ int rc;

if (blk_rq_nr_phys_segments(req) == 1) {
struct bio_vec bv = req_bvec(req);
@@ -859,26 +849,25 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
}

iod->dma_len = 0;
- iod->sg = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
- if (!iod->sg)
+ iod->sgt.sgl = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
+ if (!iod->sgt.sgl)
return BLK_STS_RESOURCE;
- sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
- iod->nents = blk_rq_map_sg(req->q, req, iod->sg);
- if (!iod->nents)
+ sg_init_table(iod->sgt.sgl, blk_rq_nr_phys_segments(req));
+ iod->sgt.orig_nents = blk_rq_map_sg(req->q, req, iod->sgt.sgl);
+ if (!iod->sgt.orig_nents)
goto out_free_sg;

- if (is_pci_p2pdma_page(sg_page(iod->sg)))
- nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
- iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN);
- else
- nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
- rq_dma_dir(req), DMA_ATTR_NO_WARN);
- if (!nr_mapped)
+ rc = dma_map_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req),
+ DMA_ATTR_NO_WARN);
+ if (rc) {
+ if (rc == -EREMOTEIO)
+ ret = BLK_STS_TARGET;
goto out_free_sg;
+ }

iod->use_sgl = nvme_pci_use_sgls(dev, req);
if (iod->use_sgl)
- ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw, nr_mapped);
+ ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw);
else
ret = nvme_pci_setup_prps(dev, req, &cmnd->rw);
if (ret != BLK_STS_OK)
@@ -886,9 +875,9 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
return BLK_STS_OK;

out_unmap_sg:
- nvme_unmap_sg(dev, req);
+ dma_unmap_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req), 0);
out_free_sg:
- mempool_free(iod->sg, dev->iod_mempool);
+ mempool_free(iod->sgt.sgl, dev->iod_mempool);
return ret;
}

@@ -912,7 +901,7 @@ static blk_status_t nvme_prep_rq(struct nvme_dev *dev, struct request *req)

iod->aborted = 0;
iod->npages = -1;
- iod->nents = 0;
+ iod->sgt.nents = 0;

ret = nvme_setup_cmd(req->q->queuedata, req);
if (ret)
--
2.30.2