iwlwifi: use threaded interrupt handler

With new transports coming up, move to threaded
interrupt handling now. This has the advantage
that we can use the same locking scheme with all
different transports we may need to implement.

Note that the TX path obviously still runs in a
tasklet, so some spin_lock() calls need to change
to spin_lock_bh() calls to properly lock out the
TX path.

In my test on a Calpella platform this has no
impact on throughput or latency.

Also add lockdep annotations to avoid lockups due
to catch sending synchronous commands or using
locks that connect with them from the irq thread.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 27 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index 0a3d4df5f434..8c7bec6b9a0b 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -65,6 +65,7 @@
 
 #include <linux/ieee80211.h>
 #include <linux/mm.h> /* for page_address */
+#include <linux/lockdep.h>
 
 #include "iwl-debug.h"
 #include "iwl-config.h"
@@ -526,6 +527,10 @@ struct iwl_trans {
 
 	struct dentry *dbgfs_dir;
 
+#ifdef CONFIG_LOCKDEP
+	struct lockdep_map sync_cmd_lockdep_map;
+#endif
+
 	/* pointer to trans specific struct */
 	/*Ensure that this pointer will always be aligned to sizeof pointer */
 	char trans_specific[0] __aligned(sizeof(void *));
@@ -602,12 +607,22 @@ static inline int iwl_trans_d3_resume(struct iwl_trans *trans,
 }
 
 static inline int iwl_trans_send_cmd(struct iwl_trans *trans,
-				struct iwl_host_cmd *cmd)
+				     struct iwl_host_cmd *cmd)
 {
+	int ret;
+
 	WARN_ONCE(trans->state != IWL_TRANS_FW_ALIVE,
 		  "%s bad state = %d", __func__, trans->state);
 
-	return trans->ops->send_cmd(trans, cmd);
+	if (!(cmd->flags & CMD_ASYNC))
+		lock_map_acquire_read(&trans->sync_cmd_lockdep_map);
+
+	ret = trans->ops->send_cmd(trans, cmd);
+
+	if (!(cmd->flags & CMD_ASYNC))
+		lock_map_release(&trans->sync_cmd_lockdep_map);
+
+	return ret;
 }
 
 static inline struct iwl_device_cmd *
@@ -791,4 +806,14 @@ iwl_trans_release_nic_access(struct iwl_trans *trans, unsigned long *flags)
 int __must_check iwl_pci_register_driver(void);
 void iwl_pci_unregister_driver(void);
 
+static inline void trans_lockdep_init(struct iwl_trans *trans)
+{
+#ifdef CONFIG_LOCKDEP
+	static struct lock_class_key __key;
+
+	lockdep_init_map(&trans->sync_cmd_lockdep_map, "sync_cmd_lockdep_map",
+			 &__key, 0);
+#endif
+}
+
 #endif /* __iwl_trans_h__ */