iwlagn: verify mutex held for sync commands

Emmanuel noticed that there's no explicit checking
that prevents the driver from attempting to issue
multiple synchronous commands at the same time and
wrote a patch to check. However, his patch warns
only if a collision actually happened, an unlikely
thing since the driver mutex should be held for
synchronous command submissions.

So instead of checking that a collision happened
add a check that the mutex is held which ensures
that collisions can't happen.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

2 files changed, 3 insertions, 11 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 8ec04f20c96a..ae2ecc24b91e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1301,7 +1301,6 @@ 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 e3e5fb614178..107b38e2ee93 100644
--- a/drivers/net/wireless/iwlwifi/iwl-hcmd.c
+++ b/drivers/net/wireless/iwlwifi/iwl-hcmd.c
@@ -171,6 +171,8 @@ int iwl_send_cmd_sync(struct iwl_priv *priv, struct iwl_host_cmd *cmd)
         int cmd_idx;
         int ret;
 
+        lockdep_assert_held(&priv->mutex);
+
         if (WARN_ON(cmd->flags & CMD_ASYNC))
                 return -EINVAL;
 
@@ -181,16 +183,7 @@ 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));
 
-        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;
-        }
-
+        set_bit(STATUS_HCMD_ACTIVE, &priv->status);
         IWL_DEBUG_INFO(priv, "Setting HCMD_ACTIVE for command %s\n",
                         get_cmd_string(cmd->id));