[PATCH v2 for-next] RDMA/hns: Fix memory corruption when allocating XRCDN

[Weihang Li <liweihang@huawei.com>]

It's incorrect to cast the type of pointer to xrcdn from (u32 *) to
(unsigned long *), then pass it into hns_roce_bitmap_alloc(), this will
lead to a memory corruption.

Fixes: 32548870d438 ("RDMA/hns: Add support for XRC on HIP09")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
---
Changes since v1:
- xrcdn won't be set if hns_roce_bitmap_alloc() fails.
- Link: https://patchwork.kernel.org/project/linux-rdma/patch/1616143536-24874-1-git-send-email-liweihang@huawei.com/

 drivers/infiniband/hw/hns/hns_roce_pd.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_pd.c b/drivers/infiniband/hw/hns/hns_roce_pd.c
index 3ca51ce..68a59ff 100644
--- a/drivers/infiniband/hw/hns/hns_roce_pd.c
+++ b/drivers/infiniband/hw/hns/hns_roce_pd.c
@@ -140,8 +140,16 @@ void hns_roce_cleanup_uar_table(struct hns_roce_dev *hr_dev)
 
 static int hns_roce_xrcd_alloc(struct hns_roce_dev *hr_dev, u32 *xrcdn)
 {
-	return hns_roce_bitmap_alloc(&hr_dev->xrcd_bitmap,
-				     (unsigned long *)xrcdn);
+	unsigned long obj;
+	int ret;
+
+	ret = hns_roce_bitmap_alloc(&hr_dev->xrcd_bitmap, &obj);
+	if (ret)
+		return ret;
+
+	*xrcdn = (u32)obj;
+
+	return 0;
 }
 
 static void hns_roce_xrcd_free(struct hns_roce_dev *hr_dev,
-- 
2.8.1