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>

6 files changed, 57 insertions, 97 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)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index e7ec12437c8b..012fc107901a 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -57,6 +57,7 @@ DEFINE_RWLOCK(hci_dev_list_lock);
 
 /* HCI callback list */
 LIST_HEAD(hci_cb_list);
+DEFINE_MUTEX(hci_cb_list_lock);
 
 /* HCI ID Numbering */
 static DEFINE_IDA(hci_index_ida);
@@ -2972,7 +2973,9 @@ int hci_register_cb(struct hci_cb *cb)
 {
 	BT_DBG("%p name %s", cb, cb->name);
 
-	list_add_tail_rcu(&cb->list, &hci_cb_list);
+	mutex_lock(&hci_cb_list_lock);
+	list_add_tail(&cb->list, &hci_cb_list);
+	mutex_unlock(&hci_cb_list_lock);
 
 	return 0;
 }
@@ -2982,8 +2985,9 @@ int hci_unregister_cb(struct hci_cb *cb)
 {
 	BT_DBG("%p name %s", cb, cb->name);
 
-	list_del_rcu(&cb->list);
-	synchronize_rcu();
+	mutex_lock(&hci_cb_list_lock);
+	list_del(&cb->list);
+	mutex_unlock(&hci_cb_list_lock);
 
 	return 0;
 }
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 44acddf58a0c..0cb52a3308ba 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -2187,11 +2187,6 @@ done:
 	return HCI_LM_ACCEPT;
 }
 
-static bool iso_match(struct hci_conn *hcon)
-{
-	return hcon->type == ISO_LINK || hcon->type == LE_LINK;
-}
-
 static void iso_connect_cfm(struct hci_conn *hcon, __u8 status)
 {
 	if (hcon->type != ISO_LINK) {
@@ -2373,7 +2368,6 @@ drop:
 
 static struct hci_cb iso_cb = {
 	.name		= "ISO",
-	.match		= iso_match,
 	.connect_cfm	= iso_connect_cfm,
 	.disconn_cfm	= iso_disconn_cfm,
 };
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index b22078b67972..c27ea70f71e1 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -7182,11 +7182,6 @@ static struct l2cap_chan *l2cap_global_fixed_chan(struct l2cap_chan *c,
 	return NULL;
 }
 
-static bool l2cap_match(struct hci_conn *hcon)
-{
-	return hcon->type == ACL_LINK || hcon->type == LE_LINK;
-}
-
 static void l2cap_connect_cfm(struct hci_conn *hcon, u8 status)
 {
 	struct hci_dev *hdev = hcon->hdev;
@@ -7194,6 +7189,9 @@ static void l2cap_connect_cfm(struct hci_conn *hcon, u8 status)
 	struct l2cap_chan *pchan;
 	u8 dst_type;
 
+	if (hcon->type != ACL_LINK && hcon->type != LE_LINK)
+		return;
+
 	BT_DBG("hcon %p bdaddr %pMR status %d", hcon, &hcon->dst, status);
 
 	if (status) {
@@ -7258,6 +7256,9 @@ int l2cap_disconn_ind(struct hci_conn *hcon)
 
 static void l2cap_disconn_cfm(struct hci_conn *hcon, u8 reason)
 {
+	if (hcon->type != ACL_LINK && hcon->type != LE_LINK)
+		return;
+
 	BT_DBG("hcon %p reason %d", hcon, reason);
 
 	l2cap_conn_del(hcon, bt_to_errno(reason));
@@ -7565,7 +7566,6 @@ unlock:
 
 static struct hci_cb l2cap_cb = {
 	.name		= "L2CAP",
-	.match		= l2cap_match,
 	.connect_cfm	= l2cap_connect_cfm,
 	.disconn_cfm	= l2cap_disconn_cfm,
 	.security_cfm	= l2cap_security_cfm,
diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
index 4c56ca5a216c..ad5177e3a69b 100644
--- a/net/bluetooth/rfcomm/core.c
+++ b/net/bluetooth/rfcomm/core.c
@@ -2134,11 +2134,6 @@ static int rfcomm_run(void *unused)
 	return 0;
 }
 
-static bool rfcomm_match(struct hci_conn *hcon)
-{
-	return hcon->type == ACL_LINK;
-}
-
 static void rfcomm_security_cfm(struct hci_conn *conn, u8 status, u8 encrypt)
 {
 	struct rfcomm_session *s;
@@ -2185,7 +2180,6 @@ static void rfcomm_security_cfm(struct hci_conn *conn, u8 status, u8 encrypt)
 
 static struct hci_cb rfcomm_cb = {
 	.name		= "RFCOMM",
-	.match		= rfcomm_match,
 	.security_cfm	= rfcomm_security_cfm
 };
 
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index ed6846864ea9..5d1bc0d6aee0 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -1407,13 +1407,11 @@ int sco_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 	return lm;
 }
 
-static bool sco_match(struct hci_conn *hcon)
-{
-	return hcon->type == SCO_LINK || hcon->type == ESCO_LINK;
-}
-
 static void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
 {
+	if (hcon->type != SCO_LINK && hcon->type != ESCO_LINK)
+		return;
+
 	BT_DBG("hcon %p bdaddr %pMR status %u", hcon, &hcon->dst, status);
 
 	if (!status) {
@@ -1430,6 +1428,9 @@ static void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
 
 static void sco_disconn_cfm(struct hci_conn *hcon, __u8 reason)
 {
+	if (hcon->type != SCO_LINK && hcon->type != ESCO_LINK)
+		return;
+
 	BT_DBG("hcon %p reason %d", hcon, reason);
 
 	sco_conn_del(hcon, bt_to_errno(reason));
@@ -1455,7 +1456,6 @@ drop:
 
 static struct hci_cb sco_cb = {
 	.name		= "SCO",
-	.match		= sco_match,
 	.connect_cfm	= sco_connect_cfm,
 	.disconn_cfm	= sco_disconn_cfm,
 };