[PATCH] rdmavt: avoid NULL pointer dereference in rvt_qp_exit()

[Natalia Petrova <n.petrova@fintech.ru>]

rvt_qp_exit() checks 'rdi->qp_dev' for NULL, but the pointer is
dereferenced before that in rvt_free_all_qps().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: f92e48718889 ("IB/rdmavt: Reset all QPs when the device is shut
down")
Signed-off-by: Natalia Petrova <n.petrova@fintech.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
 drivers/infiniband/sw/rdmavt/qp.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index 3acab569fbb9..06e755975f61 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -459,13 +459,16 @@ static unsigned rvt_free_all_qps(struct rvt_dev_info *rdi)
  */
 void rvt_qp_exit(struct rvt_dev_info *rdi)
 {
-	u32 qps_inuse = rvt_free_all_qps(rdi);
+	u32 qps_inuse = 0;
+
+	if (!rdi->qp_dev)
+		return;
+
+	qps_inuse = rvt_free_all_qps(rdi);
 
 	if (qps_inuse)
 		rvt_pr_err(rdi, "QP memory leak! %u still in use\n",
 			   qps_inuse);
-	if (!rdi->qp_dev)
-		return;
 
 	kfree(rdi->qp_dev->qp_table);
 	free_qpn_table(&rdi->qp_dev->qpn_table);
-- 
2.34.1