iwlwifi: enable serialization of synchronous commands

Until now it was only possible to have one synchronous command running at
any time. If a synchronous command is in progress when a second request
arrives then the second command will fail. Create a new mutex specific for
this purpose to only allow one synchronous command at a time, but enable
other commands to wait instead of fail if a synchronous command is in
progress.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

7 files changed, 13 insertions, 10 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 4157c6c8645f..52b6beb371fe 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -3364,6 +3364,7 @@ static int iwl_init_drv(struct iwl_priv *priv)
         INIT_LIST_HEAD(&priv->free_frames);
 
         mutex_init(&priv->mutex);
+        mutex_init(&priv->sync_cmd_mutex);
 
         /* Clear the driver's (not device's) station table */
         iwl_clear_stations_table(priv);
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 530fae8cf16d..6347d4b5c22f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -603,7 +603,7 @@ void iwlcore_free_geos(struct iwl_priv *priv);
 /*************** DRIVER STATUS FUNCTIONS   *****/
 
 #define STATUS_HCMD_ACTIVE      0       /* host command in progress */
-#define STATUS_HCMD_SYNC_ACTIVE 1       /* sync host command in progress */
+/* 1 is unused (used to be STATUS_HCMD_SYNC_ACTIVE) */
 #define STATUS_INT_ENABLED      2
 #define STATUS_RF_KILL_HW       3
 #define STATUS_CT_KILL          4
diff --git a/drivers/net/wireless/iwlwifi/iwl-debugfs.c b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
index 78298be0bdb6..7241fda022c5 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debugfs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
@@ -530,8 +530,6 @@ static ssize_t iwl_dbgfs_status_read(struct file *file,
 
         pos += scnprintf(buf + pos, bufsz - pos, "STATUS_HCMD_ACTIVE:\t %d\n",
                 test_bit(STATUS_HCMD_ACTIVE, &priv->status));
-        pos += scnprintf(buf + pos, bufsz - pos, "STATUS_HCMD_SYNC_ACTIVE: %d\n",
-                test_bit(STATUS_HCMD_SYNC_ACTIVE, &priv->status));
         pos += scnprintf(buf + pos, bufsz - pos, "STATUS_INT_ENABLED:\t %d\n",
                 test_bit(STATUS_INT_ENABLED, &priv->status));
         pos += scnprintf(buf + pos, bufsz - pos, "STATUS_RF_KILL_HW:\t %d\n",
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index f81317d478ee..021c68658718 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1111,6 +1111,7 @@ struct iwl_priv {
         spinlock_t hcmd_lock;   /* protect hcmd */
         spinlock_t reg_lock;    /* protect hw register access */
         struct mutex mutex;
+        struct mutex sync_cmd_mutex; /* enable serialization of sync commands */
 
         /* basic pci-network driver stuff */
         struct pci_dev *pci_dev;
diff --git a/drivers/net/wireless/iwlwifi/iwl-hcmd.c b/drivers/net/wireless/iwlwifi/iwl-hcmd.c
index 86783c27d97c..73681c4fefe7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-hcmd.c
+++ b/drivers/net/wireless/iwlwifi/iwl-hcmd.c
@@ -164,15 +164,13 @@ int iwl_send_cmd_sync(struct iwl_priv *priv, struct iwl_host_cmd *cmd)
          /* A synchronous command can not have a callback set. */
         BUG_ON(cmd->callback);
 
-        if (test_and_set_bit(STATUS_HCMD_SYNC_ACTIVE, &priv->status)) {
-                IWL_ERR(priv,
-                        "Error sending %s: Already sending a host command\n",
+        IWL_DEBUG_INFO(priv, "Attempting to send sync command %s\n",
                         get_cmd_string(cmd->id));
-                ret = -EBUSY;
-                goto out;
-        }
+        mutex_lock(&priv->sync_cmd_mutex);
 
         set_bit(STATUS_HCMD_ACTIVE, &priv->status);
+        IWL_DEBUG_INFO(priv, "Setting HCMD_ACTIVE for command %s \n",
+                        get_cmd_string(cmd->id));
 
         cmd_idx = iwl_enqueue_hcmd(priv, cmd);
         if (cmd_idx < 0) {
@@ -193,6 +191,8 @@ int iwl_send_cmd_sync(struct iwl_priv *priv, struct iwl_host_cmd *cmd)
                                 jiffies_to_msecs(HOST_COMPLETE_TIMEOUT));
 
                         clear_bit(STATUS_HCMD_ACTIVE, &priv->status);
+                        IWL_DEBUG_INFO(priv, "Clearing HCMD_ACTIVE for command %s \n",
+                                       get_cmd_string(cmd->id));
                         ret = -ETIMEDOUT;
                         goto cancel;
                 }
@@ -237,7 +237,7 @@ fail:
                 cmd->reply_page = 0;
         }
 out:
-        clear_bit(STATUS_HCMD_SYNC_ACTIVE, &priv->status);
+        mutex_unlock(&priv->sync_cmd_mutex);
         return ret;
 }
 EXPORT_SYMBOL(iwl_send_cmd_sync);
diff --git a/drivers/net/wireless/iwlwifi/iwl-tx.c b/drivers/net/wireless/iwlwifi/iwl-tx.c
index d8c11f955e42..38655ad8f43c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-tx.c
@@ -1238,6 +1238,8 @@ void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
 
         if (!(meta->flags & CMD_ASYNC)) {
                 clear_bit(STATUS_HCMD_ACTIVE, &priv->status);
+                IWL_DEBUG_INFO(priv, "Clearing HCMD_ACTIVE for command %s \n",
+                               get_cmd_string(cmd->hdr.cmd));
                 wake_up_interruptible(&priv->wait_command_queue);
         }
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 0e5a1ca30334..54daa38ecba3 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -3847,6 +3847,7 @@ static int iwl3945_init_drv(struct iwl_priv *priv)
         INIT_LIST_HEAD(&priv->free_frames);
 
         mutex_init(&priv->mutex);
+        mutex_init(&priv->sync_cmd_mutex);
 
         /* Clear the driver's (not device's) station table */
         iwl_clear_stations_table(priv);