[for-next PATCH v5 05/11] RDMA/rxe: Allow registering persistent flag for pmem MR only

[Li Zhijian]

Memory region could  support at most 2 flush access flags:
IB_ACCESS_FLUSH_PERSISTENT and IB_ACCESS_FLUSH_GLOBAL

But we only allow user to register persistent flush flags to the pmem MR
where it has the ability of persisting data across power cycles.

So register a persistent access flag to a non-pmem MR will be rejected.

CC: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
---
V5: make sure the whole MR is pmem
V4: set is_pmem more simple
V2: new scheme check is_pmem # Dan
    update commit message, get rid of confusing ib_check_flush_access_flags() # Tom
---
 drivers/infiniband/sw/rxe/rxe_mr.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 74a38d06332f..1da3ad5eba64 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -112,6 +112,13 @@ void rxe_mr_init_dma(int access, struct rxe_mr *mr)
 	mr->type = IB_MR_TYPE_DMA;
 }
 
+static bool vaddr_in_pmem(char *vaddr)
+{
+	return REGION_INTERSECTS ==
+	       region_intersects(virt_to_phys(vaddr), 1, IORESOURCE_MEM,
+				 IORES_DESC_PERSISTENT_MEMORY);
+}
+
 int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 		     int access, struct rxe_mr *mr)
 {
@@ -122,6 +129,7 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 	int			num_buf;
 	void			*vaddr;
 	int err;
+	bool is_pmem = false;
 	int i;
 
 	umem = ib_umem_get(&rxe->ib_dev, start, length, access);
@@ -149,6 +157,7 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 	num_buf			= 0;
 	map = mr->map;
 	if (length > 0) {
+		is_pmem = true;
 		buf = map[0]->buf;
 
 		for_each_sgtable_page (&umem->sgt_append.sgt, &sg_iter, 0) {
@@ -166,6 +175,10 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 				goto err_cleanup_map;
 			}
 
+			/* True only if the *whole* MR is pmem */
+			if (is_pmem)
+				is_pmem = vaddr_in_pmem(vaddr);
+
 			buf->addr = (uintptr_t)vaddr;
 			buf->size = PAGE_SIZE;
 			num_buf++;
@@ -174,6 +187,12 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 		}
 	}
 
+	if (!is_pmem && access & IB_ACCESS_FLUSH_PERSISTENT) {
+		pr_warn("Cannot register IB_ACCESS_FLUSH_PERSISTENT for non-pmem memory\n");
+		err = -EINVAL;
+		goto err_release_umem;
+	}
+
 	mr->umem = umem;
 	mr->access = access;
 	mr->offset = ib_umem_offset(umem);
-- 
2.31.1