iwlagn: warn about nested SYNC commands

Since there is no protection around SYNC host command mechanism, at least WARN
when collision happens between two SYNC host comamnds. I am not sure there is a
real  issue (beyond the HCMD_ACTIVE flag maintenance) with having two SYNC host
commands at the same time, but at least now, we will know about it.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

2 files changed, 11 insertions, 1 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 34f9d0f6702a..2d13d8928e2c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1300,6 +1300,7 @@ struct iwl_priv {
 
         /* command queue number */
         u8 cmd_queue;
+        u8 last_sync_cmd_id;
 
         /* max number of station keys */
         u8 sta_key_max_num;
diff --git a/drivers/net/wireless/iwlwifi/iwl-hcmd.c b/drivers/net/wireless/iwlwifi/iwl-hcmd.c
index 76f996623140..7cdb1ec73b54 100644
--- a/drivers/net/wireless/iwlwifi/iwl-hcmd.c
+++ b/drivers/net/wireless/iwlwifi/iwl-hcmd.c
@@ -181,7 +181,16 @@ int iwl_send_cmd_sync(struct iwl_priv *priv, struct iwl_host_cmd *cmd)
         IWL_DEBUG_INFO(priv, "Attempting to send sync command %s\n",
                         get_cmd_string(cmd->id));
 
-        set_bit(STATUS_HCMD_ACTIVE, &priv->status);
+        if (test_and_set_bit(STATUS_HCMD_ACTIVE, &priv->status)) {
+                IWL_ERR(priv, "STATUS_HCMD_ACTIVE already set while sending %s"
+                              ". Previous SYNC cmdn is %s\n",
+                        get_cmd_string(cmd->id),
+                        get_cmd_string(priv->last_sync_cmd_id));
+                WARN_ON(1);
+        } else {
+                priv->last_sync_cmd_id = cmd->id;
+        }
+
         IWL_DEBUG_INFO(priv, "Setting HCMD_ACTIVE for command %s\n",
                         get_cmd_string(cmd->id));