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>

6 files changed, 29 insertions, 16 deletions

diff --git a/drivers/net/wireless/mwifiex/cmdevt.c b/drivers/net/wireless/mwifiex/cmdevt.c
index 9a1302bd4c03..da469c336aa1 100644
--- a/drivers/net/wireless/mwifiex/cmdevt.c
+++ b/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);
diff --git a/drivers/net/wireless/mwifiex/init.c b/drivers/net/wireless/mwifiex/init.c
index daf8801cecd2..003c014d2176 100644
--- a/drivers/net/wireless/mwifiex/init.c
+++ b/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;
         }
 
diff --git a/drivers/net/wireless/mwifiex/main.h b/drivers/net/wireless/mwifiex/main.h
index cab8a8530944..fef89fd6d77b 100644
--- a/drivers/net/wireless/mwifiex/main.h
+++ b/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,
diff --git a/drivers/net/wireless/mwifiex/sta_cmdresp.c b/drivers/net/wireless/mwifiex/sta_cmdresp.c
index c7dc450f0bf3..9f990e14966e 100644
--- a/drivers/net/wireless/mwifiex/sta_cmdresp.c
+++ b/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;
diff --git a/drivers/net/wireless/mwifiex/sta_ioctl.c b/drivers/net/wireless/mwifiex/sta_ioctl.c
index 8c943b6ebf45..e6c9b2ae22ed 100644
--- a/drivers/net/wireless/mwifiex/sta_ioctl.c
+++ b/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));
diff --git a/drivers/net/wireless/mwifiex/util.c b/drivers/net/wireless/mwifiex/util.c
index 54667e65ca47..e57ac0dd3ab5 100644
--- a/drivers/net/wireless/mwifiex/util.c
+++ b/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);