nvme-pci: Use size_t for length fields to handle larger sizes

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>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: rleon

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;
@@ -297,6 +297,8 @@ 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);
+
+		WARN_ON_ONCE(overflows_type(vec.len, unsigned int));
 		sg_set_page(*last_sg, phys_to_page(vec.paddr), vec.len,
 				offset_in_page(vec.paddr));
 		nsegs++;
@@ -417,6 +419,8 @@ 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);
+
+		WARN_ON_ONCE(overflows_type(vec.len, unsigned int));
 		sg_set_page(sg, phys_to_page(vec.paddr), vec.len,
 				offset_in_page(vec.paddr));
 		segments++;

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;
 };