mlx4_core: Fix potential deadlock in mlx4_eq_int()

The slave_state_lock spinlock is used in both interrupt context and
process context, hence irq locking must be used.  Found by lockdep.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 11 insertions, 8 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c
index e791e705f7b1..fdc5f23d8e9f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c
@@ -1498,6 +1498,7 @@ static void mlx4_master_do_cmd(struct mlx4_dev *dev, int slave, u8 cmd,
         u32 reply;
         u8 is_going_down = 0;
         int i;
+        unsigned long flags;
 
         slave_state[slave].comm_toggle ^= 1;
         reply = (u32) slave_state[slave].comm_toggle << 31;
@@ -1576,12 +1577,12 @@ static void mlx4_master_do_cmd(struct mlx4_dev *dev, int slave, u8 cmd,
                 mlx4_warn(dev, "Bad comm cmd:%d from slave:%d\n", cmd, slave);
                 goto reset_slave;
         }
-        spin_lock(&priv->mfunc.master.slave_state_lock);
+        spin_lock_irqsave(&priv->mfunc.master.slave_state_lock, flags);
         if (!slave_state[slave].is_slave_going_down)
                 slave_state[slave].last_cmd = cmd;
         else
                 is_going_down = 1;
-        spin_unlock(&priv->mfunc.master.slave_state_lock);
+        spin_unlock_irqrestore(&priv->mfunc.master.slave_state_lock, flags);
         if (is_going_down) {
                 mlx4_warn(dev, "Slave is going down aborting command(%d)"
                           " executing from slave:%d\n",
@@ -1597,10 +1598,10 @@ static void mlx4_master_do_cmd(struct mlx4_dev *dev, int slave, u8 cmd,
 reset_slave:
         /* cleanup any slave resources */
         mlx4_delete_all_resources_for_slave(dev, slave);
-        spin_lock(&priv->mfunc.master.slave_state_lock);
+        spin_lock_irqsave(&priv->mfunc.master.slave_state_lock, flags);
         if (!slave_state[slave].is_slave_going_down)
                 slave_state[slave].last_cmd = MLX4_COMM_CMD_RESET;
-        spin_unlock(&priv->mfunc.master.slave_state_lock);
+        spin_unlock_irqrestore(&priv->mfunc.master.slave_state_lock, flags);
         /*with slave in the middle of flr, no need to clean resources again.*/
 inform_slave_state:
         memset(&slave_state[slave].event_eq, 0,
diff --git a/drivers/net/ethernet/mellanox/mlx4/eq.c b/drivers/net/ethernet/mellanox/mlx4/eq.c
index c509a86db610..3cb7727408e5 100644
--- a/drivers/net/ethernet/mellanox/mlx4/eq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/eq.c
@@ -407,6 +407,7 @@ void mlx4_master_handle_slave_flr(struct work_struct *work)
         struct mlx4_slave_state *slave_state = priv->mfunc.master.slave_state;
         int i;
         int err;
+        unsigned long flags;
 
         mlx4_dbg(dev, "mlx4_handle_slave_flr\n");
 
@@ -418,10 +419,10 @@ void mlx4_master_handle_slave_flr(struct work_struct *work)
 
                         mlx4_delete_all_resources_for_slave(dev, i);
                         /*return the slave to running mode*/
-                        spin_lock(&priv->mfunc.master.slave_state_lock);
+                        spin_lock_irqsave(&priv->mfunc.master.slave_state_lock, flags);
                         slave_state[i].last_cmd = MLX4_COMM_CMD_RESET;
                         slave_state[i].is_slave_going_down = 0;
-                        spin_unlock(&priv->mfunc.master.slave_state_lock);
+                        spin_unlock_irqrestore(&priv->mfunc.master.slave_state_lock, flags);
                         /*notify the FW:*/
                         err = mlx4_cmd(dev, 0, i, 0, MLX4_CMD_INFORM_FLR_DONE,
                                        MLX4_CMD_TIME_CLASS_A, MLX4_CMD_WRAPPED);
@@ -446,6 +447,7 @@ static int mlx4_eq_int(struct mlx4_dev *dev, struct mlx4_eq *eq)
         u8 update_slave_state;
         int i;
         enum slave_port_gen_event gen_event;
+        unsigned long flags;
 
         while ((eqe = next_eqe_sw(eq, dev->caps.eqe_factor))) {
                 /*
@@ -653,13 +655,13 @@ static int mlx4_eq_int(struct mlx4_dev *dev, struct mlx4_eq *eq)
                         } else
                                 update_slave_state = 1;
 
-                        spin_lock(&priv->mfunc.master.slave_state_lock);
+                        spin_lock_irqsave(&priv->mfunc.master.slave_state_lock, flags);
                         if (update_slave_state) {
                                 priv->mfunc.master.slave_state[flr_slave].active = false;
                                 priv->mfunc.master.slave_state[flr_slave].last_cmd = MLX4_COMM_CMD_FLR;
                                 priv->mfunc.master.slave_state[flr_slave].is_slave_going_down = 1;
                         }
-                        spin_unlock(&priv->mfunc.master.slave_state_lock);
+                        spin_unlock_irqrestore(&priv->mfunc.master.slave_state_lock, flags);
                         queue_work(priv->mfunc.master.comm_wq,
                                    &priv->mfunc.master.slave_flr_event_work);
                         break;