[PATCH] RDMA: Add ib_virt_dma_to_page()

* [PATCH] RDMA: Add ib_virt_dma_to_page()
@ 2023-03-30 14:26 Jason Gunthorpe
  2023-03-30 18:24 ` Linus Walleij
  2023-03-30 19:01 ` kernel test robot
  0 siblings, 2 replies; 5+ messages in thread
From: Jason Gunthorpe @ 2023-03-30 14:26 UTC (permalink / raw)
  To: Bernard Metzler, Leon Romanovsky, linux-rdma, Zhu Yanjun; +Cc: Linus Walleij

Make it clearer what is going on by adding a function to go back from the
"virtual" dma_addr to a struct page. This is used in the
ib_uses_virt_dma() style drivers (siw, rxe, hfi, qib).

Call it instead of a naked virt_to_page() when working with dma_addr
values encoded by the various ib_map functions.

This also fixes the vir_to_page() casting problem Linus Walleij has been
chasing.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/infiniband/sw/rxe/rxe_mr.c    | 16 ++++++++--------
 drivers/infiniband/sw/siw/siw_qp_tx.c | 12 +++---------
 include/rdma/ib_verbs.h               | 13 +++++++++++++
 3 files changed, 24 insertions(+), 17 deletions(-)

Maybe this will be clearer overall

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 1e17f8086d59a8..0e538fafcc20ff 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -210,10 +210,10 @@ int rxe_mr_init_fast(int max_pages, struct rxe_mr *mr)
 	return err;
 }
 
-static int rxe_set_page(struct ib_mr *ibmr, u64 iova)
+static int rxe_set_page(struct ib_mr *ibmr, u64 dma_addr)
 {
 	struct rxe_mr *mr = to_rmr(ibmr);
-	struct page *page = virt_to_page(iova & mr->page_mask);
+	struct page *page = ib_virt_dma_to_page(dma_addr);
 	bool persistent = !!(mr->access & IB_ACCESS_FLUSH_PERSISTENT);
 	int err;
 
@@ -279,16 +279,16 @@ static int rxe_mr_copy_xarray(struct rxe_mr *mr, u64 iova, void *addr,
 	return 0;
 }
 
-static void rxe_mr_copy_dma(struct rxe_mr *mr, u64 iova, void *addr,
+static void rxe_mr_copy_dma(struct rxe_mr *mr, u64 dma_addr, void *addr,
 			    unsigned int length, enum rxe_mr_copy_dir dir)
 {
-	unsigned int page_offset = iova & (PAGE_SIZE - 1);
+	unsigned int page_offset = dma_addr & (PAGE_SIZE - 1);
 	unsigned int bytes;
 	struct page *page;
 	u8 *va;
 
 	while (length) {
-		page = virt_to_page(iova & mr->page_mask);
+		page = ib_virt_dma_to_page(dma_addr);
 		bytes = min_t(unsigned int, length,
 				PAGE_SIZE - page_offset);
 		va = kmap_local_page(page);
@@ -300,7 +300,7 @@ static void rxe_mr_copy_dma(struct rxe_mr *mr, u64 iova, void *addr,
 
 		kunmap_local(va);
 		page_offset = 0;
-		iova += bytes;
+		dma_addr += bytes;
 		addr += bytes;
 		length -= bytes;
 	}
@@ -488,7 +488,7 @@ int rxe_mr_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 
 	if (mr->ibmr.type == IB_MR_TYPE_DMA) {
 		page_offset = iova & (PAGE_SIZE - 1);
-		page = virt_to_page(iova & PAGE_MASK);
+		page = ib_virt_dma_to_page(iova);
 	} else {
 		unsigned long index;
 		int err;
@@ -545,7 +545,7 @@ int rxe_mr_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
 
 	if (mr->ibmr.type == IB_MR_TYPE_DMA) {
 		page_offset = iova & (PAGE_SIZE - 1);
-		page = virt_to_page(iova & PAGE_MASK);
+		page = ib_virt_dma_to_page(iova);
 	} else {
 		unsigned long index;
 		int err;
diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c b/drivers/infiniband/sw/siw/siw_qp_tx.c
index 6bb9e9e81ff4ca..108985af49723b 100644
--- a/drivers/infiniband/sw/siw/siw_qp_tx.c
+++ b/drivers/infiniband/sw/siw/siw_qp_tx.c
@@ -29,7 +29,7 @@ static struct page *siw_get_pblpage(struct siw_mem *mem, u64 addr, int *idx)
 	dma_addr_t paddr = siw_pbl_get_buffer(pbl, offset, NULL, idx);
 
 	if (paddr)
-		return virt_to_page((void *)(uintptr_t)paddr);
+		return ib_virt_dma_to_page(paddr);
 
 	return NULL;
 }
@@ -537,15 +537,9 @@ static int siw_tx_hdt(struct siw_iwarp_tx *c_tx, struct socket *s)
 				 * Cast to an uintptr_t to preserve all 64 bits
 				 * in sge->laddr.
 				 */
-				uintptr_t va = (uintptr_t)(sge->laddr + sge_off);
+				u64 va = (uintptr_t)(sge->laddr + sge_off);
 
-				/*
-				 * virt_to_page() takes a (void *) pointer
-				 * so cast to a (void *) meaning it will be 64
-				 * bits on a 64 bit platform and 32 bits on a
-				 * 32 bit platform.
-				 */
-				page_array[seg] = virt_to_page((void *)(va & PAGE_MASK));
+				page_array[seg] = ib_virt_dma_to_page(va);
 				if (do_crc)
 					crypto_shash_update(
 						c_tx->mpa_crc_hd,
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 949cf4ffc536c5..4e8868171de68c 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -4035,6 +4035,19 @@ static inline bool ib_dma_pci_p2p_dma_supported(struct ib_device *dev)
 	return dma_pci_p2pdma_supported(dev->dma_device);
 }
 
+/**
+ * ib_virt_dma_to_page - Convert a dma_addr to a struct page
+ * @dma_addr: The DMA address to check
+ *
+ * Used by ib_uses_virt_dma() to get back to the struct page after
+ * going through the dma_addr marshalling.
+ */
+static inline struct page *ib_virt_dma_to_page(u64 dma_addr)
+{
+	/* virt_dma mode maps the kvs's directly into the dma addr */
+	return virt_to_page((void *)(uintptr_t)dma_addr);
+}
+
 /**
  * ib_dma_mapping_error - check a DMA addr for error
  * @dev: The device for which the dma_addr was created

base-commit: 78b26a335310a097d6b22581b706050db42f196c
-- 
2.40.0


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