[for-next PATCH v6 04/10] RDMA/rxe: Allow registering persistent flag for pmem MR only

Li Zhijian
2022-11-16T08:20:39Z

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@intel.com>
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
---
V6: Minimize pmem checking side effect # Jason
V5: make sure the whole MR is pmem # Bob
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 | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index bc081002bddc..fd423c015be0 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -111,6 +111,15 @@ void rxe_mr_init_dma(int access, struct rxe_mr *mr)
mr->ibmr.type = IB_MR_TYPE_DMA;
}

+static bool is_pmem_page(struct page *pg)
+{
+ unsigned long paddr = page_to_phys(pg);;
+
+ return REGION_INTERSECTS ==
+ region_intersects(paddr, PAGE_SIZE, 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)
{
@@ -148,16 +157,25 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
num_buf = 0;
map = mr->map;
if (length > 0) {
- buf = map[0]->buf;
+ bool persistent_access = access & IB_ACCESS_FLUSH_PERSISTENT;

+ buf = map[0]->buf;
for_each_sgtable_page (&umem->sgt_append.sgt, &sg_iter, 0) {
+ struct page *pg = sg_page_iter_page(&sg_iter);
+
+ if (persistent_access && !is_pmem_page(pg)) {
+ pr_debug("Unable to register persistent access to non-pmem device\n");
+ err = -EINVAL;
+ goto err_release_umem;
+ }
+
if (num_buf >= RXE_BUF_PER_MAP) {
map++;
buf = map[0]->buf;
num_buf = 0;
}

- vaddr = page_address(sg_page_iter_page(&sg_iter));
+ vaddr = page_address(pg);
if (!vaddr) {
pr_warn("%s: Unable to get virtual address\n",
__func__);
--
2.31.1