mwifiex: fix negative cmd_pending count

cmd_pending is increased in mwifiex_wait_queue_complete() and
decreased in mwifiex_complete_cmd() currently.
If there are two or more commands in the cmd_pending_q the main
worker thread will pick up next command from cmd_pending_q
automatically after finishing current command. As a result
mwifiex_wait_queue_complete() will not be called because
the command is alreay completed. This leads to a negative
number in cmd_pending count.

Fix it by increasing cmd_pending when a cmd is queued into
cmd_pending_q and decreasing when that cmd is recycled. For scan
commands we don't perform inc/dec operations until it's moved
from scan_pending_q to cmd_pending_q. This covers both
synchronous and asynchronous commands.
Reported-by: Daniel Drake <dsd@laptop.org>
Tested-by: Daniel Drake <dsd@laptop.org>
Tested-by: Marco Cesarano <marco@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/cmdevt.c

@@ -153,7 +153,7 @@ static int mwifiex_dnld_cmd_to_fw(struct mwifiex_private *priv,
 			" or cmd size is 0, not sending\n");
 		if (cmd_node->wait_q_enabled)
 			adapter->cmd_wait_q.status = -1;
-		mwifiex_insert_cmd_to_free_q(adapter, cmd_node);
+		mwifiex_recycle_cmd_node(adapter, cmd_node);
 		return -1;
 	}
 
@@ -167,7 +167,7 @@ static int mwifiex_dnld_cmd_to_fw(struct mwifiex_private *priv,
 			"DNLD_CMD: FW in reset state, ignore cmd %#x\n",
 			cmd_code);
 		mwifiex_complete_cmd(adapter, cmd_node);
-		mwifiex_insert_cmd_to_free_q(adapter, cmd_node);
+		mwifiex_recycle_cmd_node(adapter, cmd_node);
 		return -1;
 	}
 
@@ -228,7 +228,7 @@ static int mwifiex_dnld_cmd_to_fw(struct mwifiex_private *priv,
 			adapter->cmd_sent = false;
 		if (cmd_node->wait_q_enabled)
 			adapter->cmd_wait_q.status = -1;
-		mwifiex_insert_cmd_to_free_q(adapter, adapter->curr_cmd);
+		mwifiex_recycle_cmd_node(adapter, adapter->curr_cmd);
 
 		spin_lock_irqsave(&adapter->mwifiex_cmd_lock, flags);
 		adapter->curr_cmd = NULL;
@@ -632,6 +632,20 @@ mwifiex_insert_cmd_to_free_q(struct mwifiex_adapter *adapter,
 	spin_unlock_irqrestore(&adapter->cmd_free_q_lock, flags);
 }
 
+/* This function reuses a command node. */
+void mwifiex_recycle_cmd_node(struct mwifiex_adapter *adapter,
+			      struct cmd_ctrl_node *cmd_node)
+{
+	struct host_cmd_ds_command *host_cmd = (void *)cmd_node->cmd_skb->data;
+
+	mwifiex_insert_cmd_to_free_q(adapter, cmd_node);
+
+	atomic_dec(&adapter->cmd_pending);
+	dev_dbg(adapter->dev, "cmd: FREE_CMD: cmd=%#x, cmd_pending=%d\n",
+		le16_to_cpu(host_cmd->command),
+		atomic_read(&adapter->cmd_pending));
+}
+
 /*
  * This function queues a command to the command pending queue.
  *
@@ -673,7 +687,9 @@ mwifiex_insert_cmd_to_pending_q(struct mwifiex_adapter *adapter,
 		list_add(&cmd_node->list, &adapter->cmd_pending_q);
 	spin_unlock_irqrestore(&adapter->cmd_pending_q_lock, flags);
 
-	dev_dbg(adapter->dev, "cmd: QUEUE_CMD: cmd=%#x is queued\n", command);
+	atomic_inc(&adapter->cmd_pending);
+	dev_dbg(adapter->dev, "cmd: QUEUE_CMD: cmd=%#x, cmd_pending=%d\n",
+		command, atomic_read(&adapter->cmd_pending));
 }
 
 /*
@@ -783,7 +799,7 @@ int mwifiex_process_cmdresp(struct mwifiex_adapter *adapter)
 	if (adapter->curr_cmd->cmd_flag & CMD_F_CANCELED) {
 		dev_err(adapter->dev, "CMD_RESP: %#x been canceled\n",
 			le16_to_cpu(resp->command));
-		mwifiex_insert_cmd_to_free_q(adapter, adapter->curr_cmd);
+		mwifiex_recycle_cmd_node(adapter, adapter->curr_cmd);
 		spin_lock_irqsave(&adapter->mwifiex_cmd_lock, flags);
 		adapter->curr_cmd = NULL;
 		spin_unlock_irqrestore(&adapter->mwifiex_cmd_lock, flags);
@@ -833,7 +849,7 @@ int mwifiex_process_cmdresp(struct mwifiex_adapter *adapter)
 		if (adapter->curr_cmd->wait_q_enabled)
 			adapter->cmd_wait_q.status = -1;
 
-		mwifiex_insert_cmd_to_free_q(adapter, adapter->curr_cmd);
+		mwifiex_recycle_cmd_node(adapter, adapter->curr_cmd);
 		spin_lock_irqsave(&adapter->mwifiex_cmd_lock, flags);
 		adapter->curr_cmd = NULL;
 		spin_unlock_irqrestore(&adapter->mwifiex_cmd_lock, flags);
@@ -865,8 +881,7 @@ int mwifiex_process_cmdresp(struct mwifiex_adapter *adapter)
 		if (adapter->curr_cmd->wait_q_enabled)
 			adapter->cmd_wait_q.status = ret;
 
-		/* Clean up and put current command back to cmd_free_q */
-		mwifiex_insert_cmd_to_free_q(adapter, adapter->curr_cmd);
+		mwifiex_recycle_cmd_node(adapter, adapter->curr_cmd);
 
 		spin_lock_irqsave(&adapter->mwifiex_cmd_lock, flags);
 		adapter->curr_cmd = NULL;
@@ -993,7 +1008,7 @@ mwifiex_cancel_all_pending_cmd(struct mwifiex_adapter *adapter)
 			mwifiex_complete_cmd(adapter, cmd_node);
 			cmd_node->wait_q_enabled = false;
 		}
-		mwifiex_insert_cmd_to_free_q(adapter, cmd_node);
+		mwifiex_recycle_cmd_node(adapter, cmd_node);
 		spin_lock_irqsave(&adapter->cmd_pending_q_lock, flags);
 	}
 	spin_unlock_irqrestore(&adapter->cmd_pending_q_lock, flags);
@@ -1040,7 +1055,7 @@ mwifiex_cancel_pending_ioctl(struct mwifiex_adapter *adapter)
 		cmd_node = adapter->curr_cmd;
 		cmd_node->wait_q_enabled = false;
 		cmd_node->cmd_flag |= CMD_F_CANCELED;
-		mwifiex_insert_cmd_to_free_q(adapter, cmd_node);
+		mwifiex_recycle_cmd_node(adapter, cmd_node);
 		mwifiex_complete_cmd(adapter, adapter->curr_cmd);
 		adapter->curr_cmd = NULL;
 		spin_unlock_irqrestore(&adapter->mwifiex_cmd_lock, cmd_flags);

drivers/net/wireless/mwifiex/init.c

@@ -713,7 +713,7 @@ mwifiex_shutdown_drv(struct mwifiex_adapter *adapter)
 	if (adapter->curr_cmd) {
 		dev_warn(adapter->dev, "curr_cmd is still in processing\n");
 		del_timer(&adapter->cmd_timer);
-		mwifiex_insert_cmd_to_free_q(adapter, adapter->curr_cmd);
+		mwifiex_recycle_cmd_node(adapter, adapter->curr_cmd);
 		adapter->curr_cmd = NULL;
 	}
 

drivers/net/wireless/mwifiex/main.h

@@ -798,6 +798,8 @@ void mwifiex_cancel_pending_ioctl(struct mwifiex_adapter *adapter);
 
 void mwifiex_insert_cmd_to_free_q(struct mwifiex_adapter *adapter,
 				  struct cmd_ctrl_node *cmd_node);
+void mwifiex_recycle_cmd_node(struct mwifiex_adapter *adapter,
+			      struct cmd_ctrl_node *cmd_node);
 
 void mwifiex_insert_cmd_to_pending_q(struct mwifiex_adapter *adapter,
 				     struct cmd_ctrl_node *cmd_node,

drivers/net/wireless/mwifiex/sta_cmdresp.c

@@ -95,7 +95,7 @@ mwifiex_process_cmdresp_error(struct mwifiex_private *priv,
 		break;
 	}
 	/* Handling errors here */
-	mwifiex_insert_cmd_to_free_q(adapter, adapter->curr_cmd);
+	mwifiex_recycle_cmd_node(adapter, adapter->curr_cmd);
 
 	spin_lock_irqsave(&adapter->mwifiex_cmd_lock, flags);
 	adapter->curr_cmd = NULL;

drivers/net/wireless/mwifiex/sta_ioctl.c

@@ -59,9 +59,6 @@ int mwifiex_wait_queue_complete(struct mwifiex_adapter *adapter,
 {
 	int status;
 
-	dev_dbg(adapter->dev, "cmd pending\n");
-	atomic_inc(&adapter->cmd_pending);
-
 	/* Wait for completion */
 	status = wait_event_interruptible(adapter->cmd_wait_q.wait,
 					  *(cmd_queued->condition));

drivers/net/wireless/mwifiex/util.c

@@ -239,7 +239,6 @@ int mwifiex_recv_packet(struct mwifiex_private *priv, struct sk_buff *skb)
 int mwifiex_complete_cmd(struct mwifiex_adapter *adapter,
 			 struct cmd_ctrl_node *cmd_node)
 {
-	atomic_dec(&adapter->cmd_pending);
 	dev_dbg(adapter->dev, "cmd completed: status=%d\n",
 		adapter->cmd_wait_q.status);