[PATCH v2] net/mlx5e: fix bpf_prog reference count leaks in mlx5e_alloc_rq

[Xin Xiong]

The function invokes bpf_prog_inc(), which increases the reference
count of a bpf_prog object "rq->xdp_prog" if the object isn't NULL.

The refcount leak issues take place in two error handling paths. When
either mlx5_wq_ll_create() or mlx5_wq_cyc_create() fails, the function
simply returns the error code and forgets to drop the reference count
increased earlier, causing a reference count leak of "rq->xdp_prog".

Fix this issue by jumping to the error handling path err_rq_wq_destroy
while either function fails.

Fixes: 422d4c401edd ("net/mlx5e: RX, Split WQ objects for different RQ
types")

Signed-off-by: Xin Xiong <xiong...@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyan...@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin....@gmail.com>
---
v1 -> v2:
- Amended parts of wording to be better understood
- Added Fixes tag
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index a836a02a2116..8e1b1ab416d8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -419,7 +419,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
                err = mlx5_wq_ll_create(mdev, &rqp->wq, rqc_wq, &rq->mpwqe.wq,
                                        &rq->wq_ctrl);
                if (err)
-                       return err;
+                       goto err_rq_wq_destroy;
 
                rq->mpwqe.wq.db = &rq->mpwqe.wq.db[MLX5_RCV_DBR];
 
@@ -470,7 +470,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
                err = mlx5_wq_cyc_create(mdev, &rqp->wq, rqc_wq, &rq->wqe.wq,
                                         &rq->wq_ctrl);
                if (err)
-                       return err;
+                       goto err_rq_wq_destroy;
 
                rq->wqe.wq.db = &rq->wqe.wq.db[MLX5_RCV_DBR];
 
-- 
2.25.1