[PATCHv4 1/8] blk-mq-dma: introduce blk_map_iter
Keith Busch
kbusch at meta.com
Thu Jul 31 08:05:06 PDT 2025
From: Keith Busch <kbusch at kernel.org>
Create a type that fully captures the lower level physical address
iteration.
Signed-off-by: Keith Busch <kbusch at kernel.org>
---
block/blk-mq-dma.c | 81 +++++++++++++++++---------------------
include/linux/blk-mq-dma.h | 9 ++++-
2 files changed, 44 insertions(+), 46 deletions(-)
diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c
index ad283017caef2..ff4c9a7e19d83 100644
--- a/block/blk-mq-dma.c
+++ b/block/blk-mq-dma.c
@@ -5,13 +5,7 @@
#include <linux/blk-mq-dma.h>
#include "blk.h"
-struct phys_vec {
- phys_addr_t paddr;
- u32 len;
-};
-
-static bool blk_map_iter_next(struct request *req, struct req_iterator *iter,
- struct phys_vec *vec)
+static bool blk_map_iter_next(struct request *req, struct blk_map_iter *iter)
{
unsigned int max_size;
struct bio_vec bv;
@@ -19,8 +13,8 @@ static bool blk_map_iter_next(struct request *req, struct req_iterator *iter,
if (req->rq_flags & RQF_SPECIAL_PAYLOAD) {
if (!iter->bio)
return false;
- vec->paddr = bvec_phys(&req->special_vec);
- vec->len = req->special_vec.bv_len;
+ iter->paddr = bvec_phys(&req->special_vec);
+ iter->len = req->special_vec.bv_len;
iter->bio = NULL;
return true;
}
@@ -29,8 +23,8 @@ static bool blk_map_iter_next(struct request *req, struct req_iterator *iter,
return false;
bv = mp_bvec_iter_bvec(iter->bio->bi_io_vec, iter->iter);
- vec->paddr = bvec_phys(&bv);
- max_size = get_max_segment_size(&req->q->limits, vec->paddr, UINT_MAX);
+ iter->paddr = bvec_phys(&bv);
+ max_size = get_max_segment_size(&req->q->limits, iter->paddr, UINT_MAX);
bv.bv_len = min(bv.bv_len, max_size);
bio_advance_iter_single(iter->bio, &iter->iter, bv.bv_len);
@@ -58,7 +52,7 @@ static bool blk_map_iter_next(struct request *req, struct req_iterator *iter,
bio_advance_iter_single(iter->bio, &iter->iter, next.bv_len);
}
- vec->len = bv.bv_len;
+ iter->len = bv.bv_len;
return true;
}
@@ -77,29 +71,29 @@ static inline bool blk_can_dma_map_iova(struct request *req,
dma_get_merge_boundary(dma_dev));
}
-static bool blk_dma_map_bus(struct blk_dma_iter *iter, struct phys_vec *vec)
+static bool blk_dma_map_bus(struct blk_dma_iter *iter)
{
- iter->addr = pci_p2pdma_bus_addr_map(&iter->p2pdma, vec->paddr);
- iter->len = vec->len;
+ iter->addr = pci_p2pdma_bus_addr_map(&iter->p2pdma, iter->iter.paddr);
+ iter->len = iter->iter.len;
return true;
}
static bool blk_dma_map_direct(struct request *req, struct device *dma_dev,
- struct blk_dma_iter *iter, struct phys_vec *vec)
+ struct blk_dma_iter *iter)
{
- iter->addr = dma_map_page(dma_dev, phys_to_page(vec->paddr),
- offset_in_page(vec->paddr), vec->len, rq_dma_dir(req));
+ iter->addr = dma_map_page(dma_dev, phys_to_page(iter->iter.paddr),
+ offset_in_page(iter->iter.paddr), iter->iter.len,
+ rq_dma_dir(req));
if (dma_mapping_error(dma_dev, iter->addr)) {
iter->status = BLK_STS_RESOURCE;
return false;
}
- iter->len = vec->len;
+ iter->len = iter->iter.len;
return true;
}
static bool blk_rq_dma_map_iova(struct request *req, struct device *dma_dev,
- struct dma_iova_state *state, struct blk_dma_iter *iter,
- struct phys_vec *vec)
+ struct dma_iova_state *state, struct blk_dma_iter *iter)
{
enum dma_data_direction dir = rq_dma_dir(req);
unsigned int mapped = 0;
@@ -109,12 +103,12 @@ static bool blk_rq_dma_map_iova(struct request *req, struct device *dma_dev,
iter->len = dma_iova_size(state);
do {
- error = dma_iova_link(dma_dev, state, vec->paddr, mapped,
- vec->len, dir, 0);
+ error = dma_iova_link(dma_dev, state, iter->iter.paddr, mapped,
+ iter->iter.len, dir, 0);
if (error)
break;
- mapped += vec->len;
- } while (blk_map_iter_next(req, &iter->iter, vec));
+ mapped += iter->iter.len;
+ } while (blk_map_iter_next(req, &iter->iter));
error = dma_iova_sync(dma_dev, state, 0, mapped);
if (error) {
@@ -151,7 +145,6 @@ bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
struct dma_iova_state *state, struct blk_dma_iter *iter)
{
unsigned int total_len = blk_rq_payload_bytes(req);
- struct phys_vec vec;
iter->iter.bio = req->bio;
iter->iter.iter = req->bio->bi_iter;
@@ -162,14 +155,14 @@ bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
* Grab the first segment ASAP because we'll need it to check for P2P
* transfers.
*/
- if (!blk_map_iter_next(req, &iter->iter, &vec))
+ if (!blk_map_iter_next(req, &iter->iter))
return false;
if (IS_ENABLED(CONFIG_PCI_P2PDMA) && (req->cmd_flags & REQ_P2PDMA)) {
switch (pci_p2pdma_state(&iter->p2pdma, dma_dev,
- phys_to_page(vec.paddr))) {
+ phys_to_page(iter->iter.paddr))) {
case PCI_P2PDMA_MAP_BUS_ADDR:
- return blk_dma_map_bus(iter, &vec);
+ return blk_dma_map_bus(iter);
case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
/*
* P2P transfers through the host bridge are treated the
@@ -184,9 +177,9 @@ bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
}
if (blk_can_dma_map_iova(req, dma_dev) &&
- dma_iova_try_alloc(dma_dev, state, vec.paddr, total_len))
- return blk_rq_dma_map_iova(req, dma_dev, state, iter, &vec);
- return blk_dma_map_direct(req, dma_dev, iter, &vec);
+ dma_iova_try_alloc(dma_dev, state, iter->iter.paddr, total_len))
+ return blk_rq_dma_map_iova(req, dma_dev, state, iter);
+ return blk_dma_map_direct(req, dma_dev, iter);
}
EXPORT_SYMBOL_GPL(blk_rq_dma_map_iter_start);
@@ -211,14 +204,12 @@ EXPORT_SYMBOL_GPL(blk_rq_dma_map_iter_start);
bool blk_rq_dma_map_iter_next(struct request *req, struct device *dma_dev,
struct dma_iova_state *state, struct blk_dma_iter *iter)
{
- struct phys_vec vec;
-
- if (!blk_map_iter_next(req, &iter->iter, &vec))
+ if (!blk_map_iter_next(req, &iter->iter))
return false;
if (iter->p2pdma.map == PCI_P2PDMA_MAP_BUS_ADDR)
- return blk_dma_map_bus(iter, &vec);
- return blk_dma_map_direct(req, dma_dev, iter, &vec);
+ return blk_dma_map_bus(iter);
+ return blk_dma_map_direct(req, dma_dev, iter);
}
EXPORT_SYMBOL_GPL(blk_rq_dma_map_iter_next);
@@ -246,20 +237,20 @@ blk_next_sg(struct scatterlist **sg, struct scatterlist *sglist)
int __blk_rq_map_sg(struct request *rq, struct scatterlist *sglist,
struct scatterlist **last_sg)
{
- struct req_iterator iter = {
- .bio = rq->bio,
+ struct bio *bio = rq->bio;
+ struct blk_map_iter iter = {
+ .bio = bio,
};
- struct phys_vec vec;
int nsegs = 0;
/* the internal flush request may not have bio attached */
- if (iter.bio)
- iter.iter = iter.bio->bi_iter;
+ if (bio)
+ iter.iter = bio->bi_iter;
- while (blk_map_iter_next(rq, &iter, &vec)) {
+ while (blk_map_iter_next(rq, &iter)) {
*last_sg = blk_next_sg(last_sg, sglist);
- sg_set_page(*last_sg, phys_to_page(vec.paddr), vec.len,
- offset_in_page(vec.paddr));
+ sg_set_page(*last_sg, phys_to_page(iter.paddr), iter.len,
+ offset_in_page(iter.paddr));
nsegs++;
}
diff --git a/include/linux/blk-mq-dma.h b/include/linux/blk-mq-dma.h
index c26a01aeae006..1e5988afdb978 100644
--- a/include/linux/blk-mq-dma.h
+++ b/include/linux/blk-mq-dma.h
@@ -5,6 +5,13 @@
#include <linux/blk-mq.h>
#include <linux/pci-p2pdma.h>
+struct blk_map_iter {
+ phys_addr_t paddr;
+ u32 len;
+ struct bvec_iter iter;
+ struct bio *bio;
+};
+
struct blk_dma_iter {
/* Output address range for this iteration */
dma_addr_t addr;
@@ -14,7 +21,7 @@ struct blk_dma_iter {
blk_status_t status;
/* Internal to blk_rq_dma_map_iter_* */
- struct req_iterator iter;
+ struct blk_map_iter iter;
struct pci_p2pdma_map_state p2pdma;
};
--
2.47.3
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