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Message-ID: <6038b47007ae804f0795e5f9d9cbc9c4a63a15b2.1730037261.git.leon@kernel.org>
Date: Sun, 27 Oct 2024 16:22:00 +0200
From: Leon Romanovsky <leon@...nel.org>
To: Jens Axboe <axboe@...nel.dk>,
Jason Gunthorpe <jgg@...pe.ca>,
Robin Murphy <robin.murphy@....com>,
Joerg Roedel <joro@...tes.org>,
Will Deacon <will@...nel.org>,
Christoph Hellwig <hch@....de>,
Sagi Grimberg <sagi@...mberg.me>
Cc: Keith Busch <kbusch@...nel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Logan Gunthorpe <logang@...tatee.com>,
Yishai Hadas <yishaih@...dia.com>,
Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>,
Kevin Tian <kevin.tian@...el.com>,
Alex Williamson <alex.williamson@...hat.com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Jérôme Glisse <jglisse@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Jonathan Corbet <corbet@....net>,
linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-block@...r.kernel.org,
linux-rdma@...r.kernel.org,
iommu@...ts.linux.dev,
linux-nvme@...ts.infradead.org,
linux-pci@...r.kernel.org,
kvm@...r.kernel.org,
linux-mm@...ck.org
Subject: [RFC PATCH 7/7] nvme-pci: convert to blk_rq_dma_map
From: Christoph Hellwig <hch@....de>
Use the blk_rq_dma_map API to DMA map requests instead of
scatterlists. This also removes the fast path single segment
code as the blk_rq_dma_map naturally inlines single IOVA
segment mappings into the preallocated structure.
Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: Leon Romanovsky <leonro@...dia.com>
---
drivers/nvme/host/pci.c | 382 +++++++++++++++++++++-------------------
1 file changed, 205 insertions(+), 177 deletions(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 79cd65a5f311..f41db1efecb1 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -7,7 +7,7 @@
#include <linux/acpi.h>
#include <linux/async.h>
#include <linux/blkdev.h>
-#include <linux/blk-mq.h>
+#include <linux/blk-mq-dma.h>
#include <linux/blk-mq-pci.h>
#include <linux/blk-integrity.h>
#include <linux/dmi.h>
@@ -27,7 +27,6 @@
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/io-64-nonatomic-hi-lo.h>
#include <linux/sed-opal.h>
-#include <linux/pci-p2pdma.h>
#include "trace.h"
#include "nvme.h"
@@ -227,10 +226,9 @@ struct nvme_iod {
bool aborted;
u8 nr_descriptors; /* # of PRP/SGL descriptors */
bool large_descriptors; /* uses the full page sized descriptor pool */
- unsigned int dma_len; /* length of single DMA segment mapping */
- dma_addr_t first_dma;
+ unsigned int total_len; /* length of the entire transfer */
dma_addr_t meta_dma;
- struct sg_table sgt;
+ struct dma_iova_state dma_state;
void *descriptors[NVME_MAX_NR_DESCRIPTORS];
};
@@ -527,9 +525,14 @@ static void nvme_free_descriptors(struct nvme_dev *dev, struct request *req)
{
const int last_prp = NVME_CTRL_PAGE_SIZE / sizeof(__le64) - 1;
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- dma_addr_t dma_addr = iod->first_dma;
+ dma_addr_t dma_addr;
int i;
+ if (iod->cmd.common.flags & NVME_CMD_SGL_METABUF)
+ dma_addr = le64_to_cpu(iod->cmd.common.dptr.sgl.addr);
+ else
+ dma_addr = le64_to_cpu(iod->cmd.common.dptr.prp2);
+
if (iod->nr_descriptors == 1) {
dma_pool_free(nvme_dma_pool(dev, iod), iod->descriptors[0],
dma_addr);
@@ -545,67 +548,143 @@ static void nvme_free_descriptors(struct nvme_dev *dev, struct request *req)
}
}
-static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
+static void nvme_free_prps(struct nvme_dev *dev, struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-
- if (iod->dma_len) {
- dma_unmap_page(dev->dev, iod->first_dma, iod->dma_len,
- rq_dma_dir(req));
+ enum dma_data_direction dir = rq_dma_dir(req);
+ int length = iod->total_len;
+ dma_addr_t dma_addr;
+ int prp_len, nprps, i, desc;
+ __le64 *prp_list;
+ dma_addr_t dma_start;
+ u32 dma_len;
+
+ dma_addr = le64_to_cpu(iod->cmd.common.dptr.prp1);
+ prp_len = NVME_CTRL_PAGE_SIZE - (dma_addr & (NVME_CTRL_PAGE_SIZE - 1));
+ prp_len = min(length, prp_len);
+ length -= prp_len;
+ if (!length) {
+ dma_unmap_page(dev->dev, dma_addr, prp_len, dir);
return;
}
- WARN_ON_ONCE(!iod->sgt.nents);
+ dma_start = dma_addr;
+ dma_len = prp_len;
- dma_unmap_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req), 0);
- nvme_free_descriptors(dev, req);
- mempool_free(iod->sgt.sgl, dev->iod_mempool);
+ dma_addr = le64_to_cpu(iod->cmd.common.dptr.prp2);
+ if (length <= NVME_CTRL_PAGE_SIZE) {
+ if (dma_addr != dma_start + dma_len) {
+ dma_unmap_page(dev->dev, dma_start, dma_len, dir);
+ dma_start = dma_addr;
+ dma_len = 0;
+ }
+ dma_len += length;
+ goto done;
+ }
+
+ nprps = DIV_ROUND_UP(length, NVME_CTRL_PAGE_SIZE);
+ i = 0;
+ desc = 0;
+ prp_list = iod->descriptors[desc];
+ do {
+ if (i == NVME_CTRL_PAGE_SIZE >> 3) {
+ prp_list = iod->descriptors[++desc];
+ i = 0;
+ }
+
+ dma_addr = le64_to_cpu(prp_list[i++]);
+ if (dma_addr != dma_start + dma_len) {
+ dma_unmap_page(dev->dev, dma_start, dma_len, dir);
+ dma_start = dma_addr;
+ dma_len = 0;
+ }
+ prp_len = min(length, NVME_CTRL_PAGE_SIZE);
+ dma_len += prp_len;
+ length -= prp_len;
+ } while (length);
+done:
+ dma_unmap_page(dev->dev, dma_start, dma_len, dir);
}
-static void nvme_print_sgl(struct scatterlist *sgl, int nents)
+static void nvme_free_sgls(struct nvme_dev *dev, struct request *req)
{
- int i;
- struct scatterlist *sg;
+ struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+ dma_addr_t sqe_dma_addr = le64_to_cpu(iod->cmd.common.dptr.sgl.addr);
+ unsigned int sqe_dma_len = le32_to_cpu(iod->cmd.common.dptr.sgl.length);
+ struct nvme_sgl_desc *sg_list = iod->descriptors[0];
+ enum dma_data_direction dir = rq_dma_dir(req);
+
+ if (iod->nr_descriptors) {
+ unsigned int nr_entries = sqe_dma_len / sizeof(*sg_list), i;
+
+ for (i = 0; i < nr_entries; i++)
+ dma_unmap_page(dev->dev, le64_to_cpu(sg_list[i].addr),
+ le32_to_cpu(sg_list[i].length), dir);
+ } else {
+ dma_unmap_page(dev->dev, sqe_dma_addr, sqe_dma_len, dir);
+ }
+}
+
+static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
+{
+ struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- for_each_sg(sgl, sg, nents, i) {
- dma_addr_t phys = sg_phys(sg);
- pr_warn("sg[%d] phys_addr:%pad offset:%d length:%d "
- "dma_address:%pad dma_length:%d\n",
- i, &phys, sg->offset, sg->length, &sg_dma_address(sg),
- sg_dma_len(sg));
+ if (!blk_rq_dma_unmap(req, dev->dev, &iod->dma_state)) {
+ if (iod->cmd.common.flags & NVME_CMD_SGL_METABUF)
+ nvme_free_sgls(dev, req);
+ else
+ nvme_free_prps(dev, req);
}
+
+ if (iod->nr_descriptors)
+ nvme_free_descriptors(dev, req);
}
static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
struct request *req, struct nvme_rw_command *cmnd)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- int length = blk_rq_payload_bytes(req);
- 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);
+ unsigned int length = blk_rq_payload_bytes(req);
+ struct blk_dma_iter iter;
+ dma_addr_t prp1_dma, prp2_dma = 0;
+ unsigned int prp_len, i;
__le64 *prp_list;
- dma_addr_t prp_dma;
- int i;
- length -= (NVME_CTRL_PAGE_SIZE - offset);
- if (length <= 0) {
- iod->first_dma = 0;
+ if (!blk_rq_dma_map_iter_start(req, dev->dev, &iod->dma_state, &iter))
+ return iter.status;
+
+ /*
+ * PRP1 always points to the start of the DMA transfers.
+ *
+ * This is the only PRP (except for the list entries) that could be
+ * non-aligned.
+ */
+ prp1_dma = iter.addr;
+ prp_len = min(length, NVME_CTRL_PAGE_SIZE -
+ (iter.addr & (NVME_CTRL_PAGE_SIZE - 1)));
+ iod->total_len += prp_len;
+ iter.addr += prp_len;
+ iter.len -= prp_len;
+ length -= prp_len;
+ if (!length)
goto done;
- }
- dma_len -= (NVME_CTRL_PAGE_SIZE - offset);
- if (dma_len) {
- dma_addr += (NVME_CTRL_PAGE_SIZE - offset);
- } else {
- sg = sg_next(sg);
- dma_addr = sg_dma_address(sg);
- dma_len = sg_dma_len(sg);
+ if (!iter.len) {
+ if (!blk_rq_dma_map_iter_next(req, dev->dev, &iod->dma_state,
+ &iter)) {
+ if (WARN_ON_ONCE(!iter.status))
+ goto bad_sgl;
+ goto done;
+ }
}
+ /*
+ * PRP2 is usually a list, but can point to data if all data to be
+ * transferred fits into PRP1 + PRP2:
+ */
if (length <= NVME_CTRL_PAGE_SIZE) {
- iod->first_dma = dma_addr;
+ prp2_dma = iter.addr;
+ iod->total_len += length;
goto done;
}
@@ -614,58 +693,83 @@ static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
iod->large_descriptors = true;
prp_list = dma_pool_alloc(nvme_dma_pool(dev, iod), GFP_ATOMIC,
- &prp_dma);
- if (!prp_list)
- return BLK_STS_RESOURCE;
+ &prp2_dma);
+ if (!prp_list) {
+ iter.status = BLK_STS_RESOURCE;
+ goto done;
+ }
iod->descriptors[iod->nr_descriptors++] = prp_list;
- iod->first_dma = prp_dma;
+
i = 0;
for (;;) {
+ prp_list[i++] = cpu_to_le64(iter.addr);
+ prp_len = min(length, NVME_CTRL_PAGE_SIZE);
+ if (WARN_ON_ONCE(iter.len < prp_len))
+ goto bad_sgl;
+
+ iod->total_len += prp_len;
+ iter.addr += prp_len;
+ iter.len -= prp_len;
+ length -= prp_len;
+ if (!length)
+ break;
+
+ if (iter.len == 0) {
+ if (!blk_rq_dma_map_iter_next(req, dev->dev,
+ &iod->dma_state, &iter)) {
+ if (WARN_ON_ONCE(!iter.status))
+ goto bad_sgl;
+ goto done;
+ }
+ }
+
+ /*
+ * If we've filled the entire descriptor, allocate a new that is
+ * pointed to be the last entry in the previous PRP list. To
+ * accommodate for that move the last actual entry to the new
+ * descriptor.
+ */
if (i == NVME_CTRL_PAGE_SIZE >> 3) {
__le64 *old_prp_list = prp_list;
+ dma_addr_t prp_list_dma;
prp_list = dma_pool_alloc(dev->prp_page_pool,
- GFP_ATOMIC, &prp_dma);
- if (!prp_list)
- goto free_prps;
+ GFP_ATOMIC, &prp_list_dma);
+ if (!prp_list) {
+ iter.status = BLK_STS_RESOURCE;
+ goto done;
+ }
iod->descriptors[iod->nr_descriptors++] = prp_list;
+
prp_list[0] = old_prp_list[i - 1];
- old_prp_list[i - 1] = cpu_to_le64(prp_dma);
+ old_prp_list[i - 1] = cpu_to_le64(prp_list_dma);
i = 1;
}
- prp_list[i++] = cpu_to_le64(dma_addr);
- dma_len -= NVME_CTRL_PAGE_SIZE;
- dma_addr += NVME_CTRL_PAGE_SIZE;
- length -= NVME_CTRL_PAGE_SIZE;
- if (length <= 0)
- break;
- if (dma_len > 0)
- continue;
- if (unlikely(dma_len < 0))
- goto bad_sgl;
- sg = sg_next(sg);
- dma_addr = sg_dma_address(sg);
- dma_len = sg_dma_len(sg);
}
+
done:
- 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_descriptors(dev, req);
- return BLK_STS_RESOURCE;
+ /*
+ * nvme_unmap_data uses the DPT field in the SQE to tear down the
+ * mapping, so initialize it even for failures.
+ */
+ cmnd->dptr.prp1 = cpu_to_le64(prp1_dma);
+ cmnd->dptr.prp2 = cpu_to_le64(prp2_dma);
+ if (unlikely(iter.status))
+ nvme_unmap_data(dev, req);
+ return iter.status;
+
bad_sgl:
- 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->sgt.nents);
+ dev_err_once(dev->dev,
+ "Incorrectly formed request for payload:%d nents:%d\n",
+ blk_rq_payload_bytes(req), blk_rq_nr_phys_segments(req));
return BLK_STS_IOERR;
}
static void nvme_pci_sgl_set_data(struct nvme_sgl_desc *sge,
- struct scatterlist *sg)
+ struct blk_dma_iter *iter)
{
- sge->addr = cpu_to_le64(sg_dma_address(sg));
- sge->length = cpu_to_le32(sg_dma_len(sg));
+ sge->addr = cpu_to_le64(iter->addr);
+ sge->length = cpu_to_le32(iter->len);
sge->type = NVME_SGL_FMT_DATA_DESC << 4;
}
@@ -681,17 +785,21 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
struct request *req, struct nvme_rw_command *cmd)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+ unsigned int entries = blk_rq_nr_phys_segments(req);
struct nvme_sgl_desc *sg_list;
- struct scatterlist *sg = iod->sgt.sgl;
- unsigned int entries = iod->sgt.nents;
+ struct blk_dma_iter iter;
dma_addr_t sgl_dma;
- int i = 0;
+ unsigned int mapped = 0;
/* setting the transfer type as SGL */
cmd->flags = NVME_CMD_SGL_METABUF;
- if (entries == 1) {
- nvme_pci_sgl_set_data(&cmd->dptr.sgl, sg);
+ if (!blk_rq_dma_map_iter_start(req, dev->dev, &iod->dma_state, &iter))
+ return iter.status;
+
+ if (entries == 1 || blk_rq_dma_map_coalesce(&iod->dma_state)) {
+ nvme_pci_sgl_set_data(&cmd->dptr.sgl, &iter);
+ iod->total_len += iter.len;
return BLK_STS_OK;
}
@@ -702,110 +810,30 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
if (!sg_list)
return BLK_STS_RESOURCE;
iod->descriptors[iod->nr_descriptors++] = sg_list;
- iod->first_dma = sgl_dma;
- nvme_pci_sgl_set_seg(&cmd->dptr.sgl, sgl_dma, entries);
do {
- nvme_pci_sgl_set_data(&sg_list[i++], sg);
- sg = sg_next(sg);
- } while (--entries > 0);
-
- 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 offset = bv->bv_offset & (NVME_CTRL_PAGE_SIZE - 1);
- unsigned int first_prp_len = NVME_CTRL_PAGE_SIZE - 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);
- else
- cmnd->dptr.prp2 = 0;
- return BLK_STS_OK;
-}
-
-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);
+ if (WARN_ON_ONCE(mapped == entries)) {
+ iter.status = BLK_STS_IOERR;
+ break;
+ }
+ nvme_pci_sgl_set_data(&sg_list[mapped++], &iter);
+ iod->total_len += iter.len;
+ } while (blk_rq_dma_map_iter_next(req, dev->dev, &iod->dma_state,
+ &iter));
- 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;
+ nvme_pci_sgl_set_seg(&cmd->dptr.sgl, sgl_dma, mapped);
- cmnd->flags = NVME_CMD_SGL_METABUF;
- 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 BLK_STS_OK;
+ if (unlikely(iter.status))
+ nvme_free_sgls(dev, req);
+ return iter.status;
}
static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
struct nvme_command *cmnd)
{
- struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- blk_status_t ret = BLK_STS_RESOURCE;
- int rc;
-
- if (blk_rq_nr_phys_segments(req) == 1) {
- struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
- struct bio_vec bv = req_bvec(req);
-
- if (!is_pci_p2pdma_page(bv.bv_page)) {
- if ((bv.bv_offset & (NVME_CTRL_PAGE_SIZE - 1)) +
- bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
- return nvme_setup_prp_simple(dev, req,
- &cmnd->rw, &bv);
-
- if (nvmeq->qid && sgl_threshold &&
- nvme_ctrl_sgl_supported(&dev->ctrl))
- return nvme_setup_sgl_simple(dev, req,
- &cmnd->rw, &bv);
- }
- }
-
- iod->dma_len = 0;
- iod->sgt.sgl = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
- if (!iod->sgt.sgl)
- return BLK_STS_RESOURCE;
- 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;
-
- 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;
- }
-
- if (nvme_pci_use_sgls(dev, req, iod->sgt.nents))
- ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw);
- else
- ret = nvme_pci_setup_prps(dev, req, &cmnd->rw);
- if (ret != BLK_STS_OK)
- goto out_unmap_sg;
- return BLK_STS_OK;
-
-out_unmap_sg:
- dma_unmap_sgtable(dev->dev, &iod->sgt, rq_dma_dir(req), 0);
-out_free_sg:
- mempool_free(iod->sgt.sgl, dev->iod_mempool);
- return ret;
+ if (nvme_pci_use_sgls(dev, req, blk_rq_nr_phys_segments(req)))
+ return nvme_pci_setup_sgls(dev, req, &cmnd->rw);
+ return nvme_pci_setup_prps(dev, req, &cmnd->rw);
}
static blk_status_t nvme_map_metadata(struct nvme_dev *dev, struct request *req,
@@ -829,7 +857,7 @@ static blk_status_t nvme_prep_rq(struct nvme_dev *dev, struct request *req)
iod->aborted = false;
iod->nr_descriptors = 0;
iod->large_descriptors = false;
- iod->sgt.nents = 0;
+ iod->total_len = 0;
ret = nvme_setup_cmd(req->q->queuedata, req);
if (ret)
--
2.46.2
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