[PATCH] RDMA/restrack: Don't set RESTRACK_DD mark after a failed xa_insert()

[lirongqing]

From: Li RongQing <lirongqing@xxxxxxxxx>

When adding a QP to the restrack xarray, rdma_restrack_add() does:

	ret = xa_insert(&rt->xa, res->id, res, GFP_KERNEL);
	if (ret)
		res->id = 0;

	if (qp->qp_type >= IB_QPT_DRIVER)
		xa_set_mark(&rt->xa, res->id, RESTRACK_DD);

The xa_set_mark() call is not guarded by "!ret".  When xa_insert() fails
(possible on a qp_num collision or memory pressure), res->id is reset to
0, yet the mark is still applied to index 0.  If a legitimate QP whose
qp_num is 0 already occupies that slot - e.g. a normal QP or the SMI QP
- it is spuriously tagged as driver-private (RESTRACK_DD), and the
netlink dump path res_get_common_dumpit() then hides it from "rdma res"
output whenever the caller does not request driver details.

Only set the mark when the insertion actually succeeded by folding the
mark into the non-failure branch.

Fixes: e18fa0bbcedf8 ("RDMA/core: Add an option to display driver-specific QPs in the rdmatool")
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
---
 drivers/infiniband/core/restrack.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c
index f89a81d..a8b838f 100644
--- a/drivers/infiniband/core/restrack.c
+++ b/drivers/infiniband/core/restrack.c
@@ -250,8 +250,7 @@ void rdma_restrack_add(struct rdma_restrack_entry *res)
 		ret = xa_insert(&rt->xa, res->id, res, GFP_KERNEL);
 		if (ret)
 			res->id = 0;
-
-		if (qp->qp_type >= IB_QPT_DRIVER)
+		else if (qp->qp_type >= IB_QPT_DRIVER)
 			xa_set_mark(&rt->xa, res->id, RESTRACK_DD);
 	} else if (res->type == RDMA_RESTRACK_COUNTER) {
 		/* Special case to ensure that cntn points to right counter */
-- 
2.9.4