Revert "Bluetooth: hci_core: Fix sleeping function called from invalid context"

This reverts commit 4d94f05558271654670d18c26c912da0c1c15549 which has
problems (see [1]) and is no longer needed since 581dd2dc168f
("Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating")
has reworked the code where the original bug has been found.

[1] Link: https://lore.kernel.org/linux-bluetooth/877c55ci1r.wl-tiwai@suse.de/T/#t
Fixes: 4d94f0555827 ("Bluetooth: hci_core: Fix sleeping function called from invalid context")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

1 files changed, 38 insertions, 70 deletions

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index f756fac95488..6281063cbd8e 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -804,6 +804,7 @@ struct hci_conn_params {
 extern struct list_head hci_dev_list;
 extern struct list_head hci_cb_list;
 extern rwlock_t hci_dev_list_lock;
+extern struct mutex hci_cb_list_lock;
 
 #define hci_dev_set_flag(hdev, nr)             set_bit((nr), (hdev)->dev_flags)
 #define hci_dev_clear_flag(hdev, nr)           clear_bit((nr), (hdev)->dev_flags)
@@ -2010,47 +2011,24 @@ struct hci_cb {
 
 	char *name;
 
-	bool (*match)		(struct hci_conn *conn);
 	void (*connect_cfm)	(struct hci_conn *conn, __u8 status);
 	void (*disconn_cfm)	(struct hci_conn *conn, __u8 status);
 	void (*security_cfm)	(struct hci_conn *conn, __u8 status,
-				 __u8 encrypt);
+								__u8 encrypt);
 	void (*key_change_cfm)	(struct hci_conn *conn, __u8 status);
 	void (*role_switch_cfm)	(struct hci_conn *conn, __u8 status, __u8 role);
 };
 
-static inline void hci_cb_lookup(struct hci_conn *conn, struct list_head *list)
-{
-	struct hci_cb *cb, *cpy;
-
-	rcu_read_lock();
-	list_for_each_entry_rcu(cb, &hci_cb_list, list) {
-		if (cb->match && cb->match(conn)) {
-			cpy = kmalloc(sizeof(*cpy), GFP_ATOMIC);
-			if (!cpy)
-				break;
-
-			*cpy = *cb;
-			INIT_LIST_HEAD(&cpy->list);
-			list_add_rcu(&cpy->list, list);
-		}
-	}
-	rcu_read_unlock();
-}
-
 static inline void hci_connect_cfm(struct hci_conn *conn, __u8 status)
 {
-	struct list_head list;
-	struct hci_cb *cb, *tmp;
-
-	INIT_LIST_HEAD(&list);
-	hci_cb_lookup(conn, &list);
+	struct hci_cb *cb;
 
-	list_for_each_entry_safe(cb, tmp, &list, list) {
+	mutex_lock(&hci_cb_list_lock);
+	list_for_each_entry(cb, &hci_cb_list, list) {
 		if (cb->connect_cfm)
 			cb->connect_cfm(conn, status);
-		kfree(cb);
 	}
+	mutex_unlock(&hci_cb_list_lock);
 
 	if (conn->connect_cfm_cb)
 		conn->connect_cfm_cb(conn, status);
@@ -2058,43 +2036,22 @@ static inline void hci_connect_cfm(struct hci_conn *conn, __u8 status)
 
 static inline void hci_disconn_cfm(struct hci_conn *conn, __u8 reason)
 {
-	struct list_head list;
-	struct hci_cb *cb, *tmp;
-
-	INIT_LIST_HEAD(&list);
-	hci_cb_lookup(conn, &list);
+	struct hci_cb *cb;
 
-	list_for_each_entry_safe(cb, tmp, &list, list) {
+	mutex_lock(&hci_cb_list_lock);
+	list_for_each_entry(cb, &hci_cb_list, list) {
 		if (cb->disconn_cfm)
 			cb->disconn_cfm(conn, reason);
-		kfree(cb);
 	}
+	mutex_unlock(&hci_cb_list_lock);
 
 	if (conn->disconn_cfm_cb)
 		conn->disconn_cfm_cb(conn, reason);
 }
 
-static inline void hci_security_cfm(struct hci_conn *conn, __u8 status,
-				    __u8 encrypt)
-{
-	struct list_head list;
-	struct hci_cb *cb, *tmp;
-
-	INIT_LIST_HEAD(&list);
-	hci_cb_lookup(conn, &list);
-
-	list_for_each_entry_safe(cb, tmp, &list, list) {
-		if (cb->security_cfm)
-			cb->security_cfm(conn, status, encrypt);
-		kfree(cb);
-	}
-
-	if (conn->security_cfm_cb)
-		conn->security_cfm_cb(conn, status);
-}
-
 static inline void hci_auth_cfm(struct hci_conn *conn, __u8 status)
 {
+	struct hci_cb *cb;
 	__u8 encrypt;
 
 	if (test_bit(HCI_CONN_ENCRYPT_PEND, &conn->flags))
@@ -2102,11 +2059,20 @@ static inline void hci_auth_cfm(struct hci_conn *conn, __u8 status)
 
 	encrypt = test_bit(HCI_CONN_ENCRYPT, &conn->flags) ? 0x01 : 0x00;
 
-	hci_security_cfm(conn, status, encrypt);
+	mutex_lock(&hci_cb_list_lock);
+	list_for_each_entry(cb, &hci_cb_list, list) {
+		if (cb->security_cfm)
+			cb->security_cfm(conn, status, encrypt);
+	}
+	mutex_unlock(&hci_cb_list_lock);
+
+	if (conn->security_cfm_cb)
+		conn->security_cfm_cb(conn, status);
 }
 
 static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status)
 {
+	struct hci_cb *cb;
 	__u8 encrypt;
 
 	if (conn->state == BT_CONFIG) {
@@ -2133,38 +2099,40 @@ static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status)
 			conn->sec_level = conn->pending_sec_level;
 	}
 
-	hci_security_cfm(conn, status, encrypt);
+	mutex_lock(&hci_cb_list_lock);
+	list_for_each_entry(cb, &hci_cb_list, list) {
+		if (cb->security_cfm)
+			cb->security_cfm(conn, status, encrypt);
+	}
+	mutex_unlock(&hci_cb_list_lock);
+
+	if (conn->security_cfm_cb)
+		conn->security_cfm_cb(conn, status);
 }
 
 static inline void hci_key_change_cfm(struct hci_conn *conn, __u8 status)
 {
-	struct list_head list;
-	struct hci_cb *cb, *tmp;
-
-	INIT_LIST_HEAD(&list);
-	hci_cb_lookup(conn, &list);
+	struct hci_cb *cb;
 
-	list_for_each_entry_safe(cb, tmp, &list, list) {
+	mutex_lock(&hci_cb_list_lock);
+	list_for_each_entry(cb, &hci_cb_list, list) {
 		if (cb->key_change_cfm)
 			cb->key_change_cfm(conn, status);
-		kfree(cb);
 	}
+	mutex_unlock(&hci_cb_list_lock);
 }
 
 static inline void hci_role_switch_cfm(struct hci_conn *conn, __u8 status,
 								__u8 role)
 {
-	struct list_head list;
-	struct hci_cb *cb, *tmp;
-
-	INIT_LIST_HEAD(&list);
-	hci_cb_lookup(conn, &list);
+	struct hci_cb *cb;
 
-	list_for_each_entry_safe(cb, tmp, &list, list) {
+	mutex_lock(&hci_cb_list_lock);
+	list_for_each_entry(cb, &hci_cb_list, list) {
 		if (cb->role_switch_cfm)
 			cb->role_switch_cfm(conn, status, role);
-		kfree(cb);
 	}
+	mutex_unlock(&hci_cb_list_lock);
 }
 
 static inline bool hci_bdaddr_is_rpa(bdaddr_t *bdaddr, u8 addr_type)