net/mlx5: Fix potential deadlock in command mode change
authorMohamad Haj Yahia <mohamad@mellanox.com>
Thu, 30 Jun 2016 14:34:42 +0000 (17:34 +0300)
committerDavid S. Miller <davem@davemloft.net>
Fri, 1 Jul 2016 10:12:03 +0000 (06:12 -0400)
Call command completion handler in case of timeout when working in
interrupts mode.
Avoid flushing the commands workqueue after acquiring the semaphores to
prevent a potential deadlock.

Fixes: e126ba97dba9 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Mohamad Haj Yahia <mohamad@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/mellanox/mlx5/core/cmd.c

index fda43bc5feadfa622af28a56d32c16b0c37aa26e..74067f547aa6f853d0c0a21512dc5867f03d70c9 100644 (file)
@@ -710,13 +710,13 @@ static int wait_func(struct mlx5_core_dev *dev, struct mlx5_cmd_work_ent *ent)
 
        if (cmd->mode == CMD_MODE_POLLING) {
                wait_for_completion(&ent->done);
-               err = ent->ret;
-       } else {
-               if (!wait_for_completion_timeout(&ent->done, timeout))
-                       err = -ETIMEDOUT;
-               else
-                       err = 0;
+       } else if (!wait_for_completion_timeout(&ent->done, timeout)) {
+               ent->ret = -ETIMEDOUT;
+               mlx5_cmd_comp_handler(dev, 1UL << ent->idx);
        }
+
+       err = ent->ret;
+
        if (err == -ETIMEDOUT) {
                mlx5_core_warn(dev, "%s(0x%x) timeout. Will cause a leak of a command resource\n",
                               mlx5_command_str(msg_to_opcode(ent->in)),
@@ -774,28 +774,26 @@ static int mlx5_cmd_invoke(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *in,
                goto out_free;
        }
 
-       if (!callback) {
-               err = wait_func(dev, ent);
-               if (err == -ETIMEDOUT)
-                       goto out;
-
-               ds = ent->ts2 - ent->ts1;
-               op = be16_to_cpu(((struct mlx5_inbox_hdr *)in->first.data)->opcode);
-               if (op < ARRAY_SIZE(cmd->stats)) {
-                       stats = &cmd->stats[op];
-                       spin_lock_irq(&stats->lock);
-                       stats->sum += ds;
-                       ++stats->n;
-                       spin_unlock_irq(&stats->lock);
-               }
-               mlx5_core_dbg_mask(dev, 1 << MLX5_CMD_TIME,
-                                  "fw exec time for %s is %lld nsec\n",
-                                  mlx5_command_str(op), ds);
-               *status = ent->status;
-               free_cmd(ent);
-       }
+       if (callback)
+               goto out;
 
-       return err;
+       err = wait_func(dev, ent);
+       if (err == -ETIMEDOUT)
+               goto out_free;
+
+       ds = ent->ts2 - ent->ts1;
+       op = be16_to_cpu(((struct mlx5_inbox_hdr *)in->first.data)->opcode);
+       if (op < ARRAY_SIZE(cmd->stats)) {
+               stats = &cmd->stats[op];
+               spin_lock_irq(&stats->lock);
+               stats->sum += ds;
+               ++stats->n;
+               spin_unlock_irq(&stats->lock);
+       }
+       mlx5_core_dbg_mask(dev, 1 << MLX5_CMD_TIME,
+                          "fw exec time for %s is %lld nsec\n",
+                          mlx5_command_str(op), ds);
+       *status = ent->status;
 
 out_free:
        free_cmd(ent);
@@ -1185,41 +1183,30 @@ err_dbg:
        return err;
 }
 
-void mlx5_cmd_use_events(struct mlx5_core_dev *dev)
+static void mlx5_cmd_change_mod(struct mlx5_core_dev *dev, int mode)
 {
        struct mlx5_cmd *cmd = &dev->cmd;
        int i;
 
        for (i = 0; i < cmd->max_reg_cmds; i++)
                down(&cmd->sem);
-
        down(&cmd->pages_sem);
 
-       flush_workqueue(cmd->wq);
-
-       cmd->mode = CMD_MODE_EVENTS;
+       cmd->mode = mode;
 
        up(&cmd->pages_sem);
        for (i = 0; i < cmd->max_reg_cmds; i++)
                up(&cmd->sem);
 }
 
-void mlx5_cmd_use_polling(struct mlx5_core_dev *dev)
+void mlx5_cmd_use_events(struct mlx5_core_dev *dev)
 {
-       struct mlx5_cmd *cmd = &dev->cmd;
-       int i;
-
-       for (i = 0; i < cmd->max_reg_cmds; i++)
-               down(&cmd->sem);
-
-       down(&cmd->pages_sem);
-
-       flush_workqueue(cmd->wq);
-       cmd->mode = CMD_MODE_POLLING;
+       mlx5_cmd_change_mod(dev, CMD_MODE_EVENTS);
+}
 
-       up(&cmd->pages_sem);
-       for (i = 0; i < cmd->max_reg_cmds; i++)
-               up(&cmd->sem);
+void mlx5_cmd_use_polling(struct mlx5_core_dev *dev)
+{
+       mlx5_cmd_change_mod(dev, CMD_MODE_POLLING);
 }
 
 static void free_msg(struct mlx5_core_dev *dev, struct mlx5_cmd_msg *msg)