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nvme-pci: convert metadata mapping to dma iter

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Aligns data and metadata to the similar dma mapping scheme and removes
one more user of the scatter-gather dma mapping.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250813153153.3260897-10-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Keith Busch 2025-08-13 08:31:53 -07:00 committed by Jens Axboe
parent f0887e2a52
commit 94ce55046c
1 changed files with 87 additions and 76 deletions
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163
drivers/nvme/host/pci.c
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@ -172,9 +172,7 @@ struct nvme_dev {
u32 last_ps;
bool hmb;
struct sg_table *hmb_sgt;
mempool_t *dmavec_mempool;
mempool_t *iod_meta_mempool;
/* shadow doorbell buffer support: */
__le32 *dbbuf_dbs;
@ -264,6 +262,12 @@ enum nvme_iod_flags {
/* DMA mapped with PCI_P2PDMA_MAP_BUS_ADDR */
IOD_P2P_BUS_ADDR = 1U << 3,
/* Metadata DMA mapped with PCI_P2PDMA_MAP_BUS_ADDR */
IOD_META_P2P_BUS_ADDR = 1U << 4,
/* Metadata using non-coalesced MPTR */
IOD_SINGLE_META_SEGMENT = 1U << 5,
};
struct nvme_dma_vec {
@ -287,7 +291,8 @@ struct nvme_iod {
unsigned int nr_dma_vecs;
dma_addr_t meta_dma;
struct sg_table meta_sgt;
unsigned int meta_total_len;
struct dma_iova_state meta_dma_state;
struct nvme_sgl_desc *meta_descriptor;
};
@ -644,6 +649,11 @@ static inline struct dma_pool *nvme_dma_pool(struct nvme_queue *nvmeq,
return nvmeq->descriptor_pools.large;
}
static inline bool nvme_pci_cmd_use_meta_sgl(struct nvme_command *cmd)
{
return (cmd->common.flags & NVME_CMD_SGL_ALL) == NVME_CMD_SGL_METASEG;
}
static inline bool nvme_pci_cmd_use_sgl(struct nvme_command *cmd)
{
return cmd->common.flags &
@ -712,6 +722,36 @@ static void nvme_free_sgls(struct request *req, struct nvme_sgl_desc *sge,
le32_to_cpu(sg_list[i].length), dir);
}
static void nvme_unmap_metadata(struct request *req)
{
struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
enum dma_data_direction dir = rq_dma_dir(req);
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
struct device *dma_dev = nvmeq->dev->dev;
struct nvme_sgl_desc *sge = iod->meta_descriptor;
if (iod->flags & IOD_SINGLE_META_SEGMENT) {
dma_unmap_page(dma_dev, iod->meta_dma,
rq_integrity_vec(req).bv_len,
rq_dma_dir(req));
return;
}
if (!blk_rq_dma_unmap(req, dma_dev, &iod->meta_dma_state,
iod->meta_total_len,
iod->flags & IOD_META_P2P_BUS_ADDR)) {
if (nvme_pci_cmd_use_meta_sgl(&iod->cmd))
nvme_free_sgls(req, sge, &sge[1]);
else
dma_unmap_page(dma_dev, iod->meta_dma,
iod->meta_total_len, dir);
}
if (iod->meta_descriptor)
dma_pool_free(nvmeq->descriptor_pools.small,
iod->meta_descriptor, iod->meta_dma);
}
static void nvme_unmap_data(struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
@ -1013,70 +1053,72 @@ static blk_status_t nvme_map_data(struct request *req)
return nvme_pci_setup_data_prp(req, &iter);
}
static void nvme_pci_sgl_set_data_sg(struct nvme_sgl_desc *sge,
struct scatterlist *sg)
{
sge->addr = cpu_to_le64(sg_dma_address(sg));
sge->length = cpu_to_le32(sg_dma_len(sg));
sge->type = NVME_SGL_FMT_DATA_DESC << 4;
}
static blk_status_t nvme_pci_setup_meta_sgls(struct request *req)
{
struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
struct nvme_dev *dev = nvmeq->dev;
unsigned int entries = req->nr_integrity_segments;
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
struct nvme_dev *dev = nvmeq->dev;
struct nvme_sgl_desc *sg_list;
struct scatterlist *sgl, *sg;
unsigned int entries;
struct blk_dma_iter iter;
dma_addr_t sgl_dma;
int rc, i;
int i = 0;
iod->meta_sgt.sgl = mempool_alloc(dev->iod_meta_mempool, GFP_ATOMIC);
if (!iod->meta_sgt.sgl)
return BLK_STS_RESOURCE;
if (!blk_rq_integrity_dma_map_iter_start(req, dev->dev,
&iod->meta_dma_state, &iter))
return iter.status;
sg_init_table(iod->meta_sgt.sgl, req->nr_integrity_segments);
iod->meta_sgt.orig_nents = blk_rq_map_integrity_sg(req,
iod->meta_sgt.sgl);
if (!iod->meta_sgt.orig_nents)
goto out_free_sg;
if (iter.p2pdma.map == PCI_P2PDMA_MAP_BUS_ADDR)
iod->flags |= IOD_META_P2P_BUS_ADDR;
else if (blk_rq_dma_map_coalesce(&iod->meta_dma_state))
entries = 1;
rc = dma_map_sgtable(dev->dev, &iod->meta_sgt, rq_dma_dir(req),
DMA_ATTR_NO_WARN);
if (rc)
goto out_free_sg;
/*
* The NVMe MPTR descriptor has an implicit length that the host and
* device must agree on to avoid data/memory corruption. We trust the
* kernel allocated correctly based on the format's parameters, so use
* the more efficient MPTR to avoid extra dma pool allocations for the
* SGL indirection.
*
* But for user commands, we don't necessarily know what they do, so
* the driver can't validate the metadata buffer size. The SGL
* descriptor provides an explicit length, so we're relying on that
* mechanism to catch any misunderstandings between the application and
* device.
*/
if (entries == 1 && !(nvme_req(req)->flags & NVME_REQ_USERCMD)) {
iod->cmd.common.metadata = cpu_to_le64(iter.addr);
iod->meta_total_len = iter.len;
iod->meta_dma = iter.addr;
iod->meta_descriptor = NULL;
return BLK_STS_OK;
}
sg_list = dma_pool_alloc(nvmeq->descriptor_pools.small, GFP_ATOMIC,
&sgl_dma);
if (!sg_list)
goto out_unmap_sg;
return BLK_STS_RESOURCE;
entries = iod->meta_sgt.nents;
iod->meta_descriptor = sg_list;
iod->meta_dma = sgl_dma;
iod->cmd.common.flags = NVME_CMD_SGL_METASEG;
iod->cmd.common.metadata = cpu_to_le64(sgl_dma);
sgl = iod->meta_sgt.sgl;
if (entries == 1) {
nvme_pci_sgl_set_data_sg(sg_list, sgl);
iod->meta_total_len = iter.len;
nvme_pci_sgl_set_data(sg_list, &iter);
return BLK_STS_OK;
}
sgl_dma += sizeof(*sg_list);
nvme_pci_sgl_set_seg(sg_list, sgl_dma, entries);
for_each_sg(sgl, sg, entries, i)
nvme_pci_sgl_set_data_sg(&sg_list[i + 1], sg);
do {
nvme_pci_sgl_set_data(&sg_list[++i], &iter);
iod->meta_total_len += iter.len;
} while (blk_rq_integrity_dma_map_iter_next(req, dev->dev, &iter));
return BLK_STS_OK;
out_unmap_sg:
dma_unmap_sgtable(dev->dev, &iod->meta_sgt, rq_dma_dir(req), 0);
out_free_sg:
mempool_free(iod->meta_sgt.sgl, dev->iod_meta_mempool);
return BLK_STS_RESOURCE;
nvme_pci_sgl_set_seg(sg_list, sgl_dma, i);
if (unlikely(iter.status))
nvme_unmap_metadata(req);
return iter.status;
}
static blk_status_t nvme_pci_setup_meta_mptr(struct request *req)
@ -1089,6 +1131,7 @@ static blk_status_t nvme_pci_setup_meta_mptr(struct request *req)
if (dma_mapping_error(nvmeq->dev->dev, iod->meta_dma))
return BLK_STS_IOERR;
iod->cmd.common.metadata = cpu_to_le64(iod->meta_dma);
iod->flags |= IOD_SINGLE_META_SEGMENT;
return BLK_STS_OK;
}
@ -1110,7 +1153,7 @@ static blk_status_t nvme_prep_rq(struct request *req)
iod->flags = 0;
iod->nr_descriptors = 0;
iod->total_len = 0;
iod->meta_sgt.nents = 0;
iod->meta_total_len = 0;
ret = nvme_setup_cmd(req->q->queuedata, req);
if (ret)
@ -1221,25 +1264,6 @@ static void nvme_queue_rqs(struct rq_list *rqlist)
*rqlist = requeue_list;
}
static __always_inline void nvme_unmap_metadata(struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
struct nvme_dev *dev = nvmeq->dev;
if (!iod->meta_sgt.nents) {
dma_unmap_page(dev->dev, iod->meta_dma,
rq_integrity_vec(req).bv_len,
rq_dma_dir(req));
return;
}
dma_pool_free(nvmeq->descriptor_pools.small, iod->meta_descriptor,
iod->meta_dma);
dma_unmap_sgtable(dev->dev, &iod->meta_sgt, rq_dma_dir(req), 0);
mempool_free(iod->meta_sgt.sgl, dev->iod_meta_mempool);
}
static __always_inline void nvme_pci_unmap_rq(struct request *req)
{
if (blk_integrity_rq(req))
@ -3045,7 +3069,6 @@ static int nvme_disable_prepare_reset(struct nvme_dev *dev, bool shutdown)
static int nvme_pci_alloc_iod_mempool(struct nvme_dev *dev)
{
size_t meta_size = sizeof(struct scatterlist) * (NVME_MAX_META_SEGS + 1);
size_t alloc_size = sizeof(struct nvme_dma_vec) * NVME_MAX_SEGS;
dev->dmavec_mempool = mempool_create_node(1,
@ -3054,17 +3077,7 @@ static int nvme_pci_alloc_iod_mempool(struct nvme_dev *dev)
dev_to_node(dev->dev));
if (!dev->dmavec_mempool)
return -ENOMEM;
dev->iod_meta_mempool = mempool_create_node(1,
mempool_kmalloc, mempool_kfree,
(void *)meta_size, GFP_KERNEL,
dev_to_node(dev->dev));
if (!dev->iod_meta_mempool)
goto free;
return 0;
free:
mempool_destroy(dev->dmavec_mempool);
return -ENOMEM;
}
static void nvme_free_tagset(struct nvme_dev *dev)
@ -3514,7 +3527,6 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
nvme_free_queues(dev, 0);
out_release_iod_mempool:
mempool_destroy(dev->dmavec_mempool);
mempool_destroy(dev->iod_meta_mempool);
out_dev_unmap:
nvme_dev_unmap(dev);
out_uninit_ctrl:
@ -3578,7 +3590,6 @@ static void nvme_remove(struct pci_dev *pdev)
nvme_dbbuf_dma_free(dev);
nvme_free_queues(dev, 0);
mempool_destroy(dev->dmavec_mempool);
mempool_destroy(dev->iod_meta_mempool);
nvme_release_descriptor_pools(dev);
nvme_dev_unmap(dev);
nvme_uninit_ctrl(&dev->ctrl);