[PATCH AUTOSEL 4.9 23/27] net/mlx4_core: Fix use of ENOSPC around mlx4_counter_alloc()

[Sasha Levin]

From: Tariq Toukan <tariqt@xxxxxxxxxxxx>

[ Upstream commit 40e473071dbad04316ddc3613c3a3d1c75458299 ]

When ENOSPC is set the idx is still valid and gets set to the global
MLX4_SINK_COUNTER_INDEX.  However gcc's static analysis cannot tell that
ENOSPC is impossible from mlx4_cmd_imm() and gives this warning:

drivers/net/ethernet/mellanox/mlx4/main.c:2552:28: warning: 'idx' may be
used uninitialized in this function [-Wmaybe-uninitialized]
 2552 |    priv->def_counter[port] = idx;

Also, when ENOSPC is returned mlx4_allocate_default_counters should not
fail.

Fixes: 6de5f7f6a1fa ("net/mlx4_core: Allocate default counter per port")
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx4/main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 781642d47133d..751aac54f2d55 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -2478,6 +2478,7 @@ static int mlx4_allocate_default_counters(struct mlx4_dev *dev)
 
 		if (!err || err == -ENOSPC) {
 			priv->def_counter[port] = idx;
+			err = 0;
 		} else if (err == -ENOENT) {
 			err = 0;
 			continue;
@@ -2527,7 +2528,8 @@ int mlx4_counter_alloc(struct mlx4_dev *dev, u32 *idx)
 				   MLX4_CMD_TIME_CLASS_A, MLX4_CMD_WRAPPED);
 		if (!err)
 			*idx = get_param_l(&out_param);
-
+		if (WARN_ON(err == -ENOSPC))
+			err = -EINVAL;
 		return err;
 	}
 	return __mlx4_counter_alloc(dev, idx);
-- 
2.20.1