[PATCH 1/2] nvme-pci: Use size_t for length fields to handle larger sizes

Leon Romanovsky
2025-11-15T16:23:05Z

From: Leon Romanovsky <leonro@nvidia.com>

This patch changes the length variables from unsigned int to size_t.
Using size_t ensures that we can handle larger sizes, as size_t is
always equal to or larger than the previously used u32 type.

Originally, u32 was used because blk-mq-dma code evolved from
scatter-gather implementation, which uses unsigned int to describe length.
This change will also allow us to reuse the existing struct phys_vec in places
that don't need scatter-gather.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
block/blk-mq-dma.c | 14 +++++++++-----
drivers/nvme/host/pci.c | 4 ++--
2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c
index e9108ccaf4b0..cc3e2548cc30 100644
--- a/block/blk-mq-dma.c
+++ b/block/blk-mq-dma.c
@@ -8,7 +8,7 @@

struct phys_vec {
phys_addr_t paddr;
- u32 len;
+ size_t len;
};

static bool __blk_map_iter_next(struct blk_map_iter *iter)
@@ -112,8 +112,8 @@ static bool blk_rq_dma_map_iova(struct request *req, struct device *dma_dev,
struct phys_vec *vec)
{
enum dma_data_direction dir = rq_dma_dir(req);
- unsigned int mapped = 0;
unsigned int attrs = 0;
+ size_t mapped = 0;
int error;

iter->addr = state->addr;
@@ -296,8 +296,10 @@ int __blk_rq_map_sg(struct request *rq, struct scatterlist *sglist,
blk_rq_map_iter_init(rq, &iter);
while (blk_map_iter_next(rq, &iter, &vec)) {
*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));
+
+ WARN_ON_ONCE(overflows_type(vec.len, unsigned int));
+ sg_set_page(*last_sg, phys_to_page(vec.paddr),
+ (unsigned int)vec.len, offset_in_page(vec.paddr));
nsegs++;
}

@@ -416,7 +418,9 @@ int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist)

while (blk_map_iter_next(rq, &iter, &vec)) {
sg = blk_next_sg(&sg, sglist);
- sg_set_page(sg, phys_to_page(vec.paddr), vec.len,
+
+ WARN_ON_ONCE(overflows_type(vec.len, unsigned int));
+ sg_set_page(sg, phys_to_page(vec.paddr), (unsigned int)vec.len,
offset_in_page(vec.paddr));
segments++;
}
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 9085bed107fd..de512efa742d 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -290,14 +290,14 @@ struct nvme_iod {
u8 flags;
u8 nr_descriptors;

- unsigned int total_len;
+ size_t total_len;
struct dma_iova_state dma_state;
void *descriptors[NVME_MAX_NR_DESCRIPTORS];
struct nvme_dma_vec *dma_vecs;
unsigned int nr_dma_vecs;

dma_addr_t meta_dma;
- unsigned int meta_total_len;
+ size_t meta_total_len;
struct dma_iova_state meta_dma_state;
struct nvme_sgl_desc *meta_descriptor;
};

--
2.51.1