Bluetooth: Use struct list_head for L2CAP channels list

Use a well known Kernel API is always a good idea than implement your own
list.
In the future we might use RCU on this list.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

2 files changed, 88 insertions, 112 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 6378bcc94e2b..ddf4bc56a5b5 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -277,16 +277,9 @@ struct l2cap_conn_param_update_rsp {
 #define L2CAP_CONN_PARAM_REJECTED       0x0001
 
 /* ----- L2CAP channels and connections ----- */
-
 struct l2cap_chan {
         struct sock *sk;
-        struct l2cap_chan       *next_c;
-        struct l2cap_chan       *prev_c;
-};
-
-struct l2cap_chan_list {
-        struct l2cap_chan *head;
-        rwlock_t        lock;
+        struct list_head list;
 };
 
 struct l2cap_conn {
@@ -312,7 +305,8 @@ struct l2cap_conn {
 
         __u8            disc_reason;
 
-        struct l2cap_chan_list chan_list;
+        struct list_head chan_l;
+        rwlock_t        chan_lock;
 };
 
 struct sock_del_list {
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index e49d8f7b80a5..0dbbaf394c13 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -74,66 +74,75 @@ static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
 static int l2cap_ertm_data_rcv(struct sock *sk, struct sk_buff *skb);
 
 /* ---- L2CAP channels ---- */
-static struct l2cap_chan *__l2cap_get_chan_by_dcid(struct l2cap_chan_list *l, u16 cid)
+static struct l2cap_chan *__l2cap_get_chan_by_dcid(struct l2cap_conn *conn, u16 cid)
 {
         struct l2cap_chan *c;
-        for (c = l->head; c; c = c->next_c) {
-                if (l2cap_pi(c->sk)->dcid == cid)
-                        break;
+
+        list_for_each_entry(c, &conn->chan_l, list) {
+                struct sock *s = c->sk;
+                if (l2cap_pi(s)->dcid == cid)
+                        return c;
         }
-        return c;
+        return NULL;
+
 }
 
-static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_chan_list *l, u16 cid)
+static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid)
 {
         struct l2cap_chan *c;
-        for (c = l->head; c; c = c->next_c) {
-                if (l2cap_pi(c->sk)->scid == cid)
-                        break;
+
+        list_for_each_entry(c, &conn->chan_l, list) {
+                struct sock *s = c->sk;
+                if (l2cap_pi(s)->scid == cid)
+                        return c;
         }
-        return c;
+        return NULL;
 }
 
 /* Find channel with given SCID.
  * Returns locked socket */
-static inline struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_chan_list *l, u16 cid)
+static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid)
 {
         struct l2cap_chan *c;
-        read_lock(&l->lock);
-        c = __l2cap_get_chan_by_scid(l, cid);
+
+        read_lock(&conn->chan_lock);
+        c = __l2cap_get_chan_by_scid(conn, cid);
         if (c)
                 bh_lock_sock(c->sk);
-        read_unlock(&l->lock);
+        read_unlock(&conn->chan_lock);
         return c;
 }
 
-static struct l2cap_chan *__l2cap_get_chan_by_ident(struct l2cap_chan_list *l, u8 ident)
+static struct l2cap_chan *__l2cap_get_chan_by_ident(struct l2cap_conn *conn, u8 ident)
 {
         struct l2cap_chan *c;
-        for (c = l->head; c; c = c->next_c) {
-                if (l2cap_pi(c->sk)->ident == ident)
-                        break;
+
+        list_for_each_entry(c, &conn->chan_l, list) {
+                struct sock *s = c->sk;
+                if (l2cap_pi(s)->ident == ident)
+                        return c;
         }
-        return c;
+        return NULL;
 }
 
-static inline struct l2cap_chan *l2cap_get_chan_by_ident(struct l2cap_chan_list *l, u8 ident)
+static inline struct l2cap_chan *l2cap_get_chan_by_ident(struct l2cap_conn *conn, u8 ident)
 {
         struct l2cap_chan *c;
-        read_lock(&l->lock);
-        c = __l2cap_get_chan_by_ident(l, ident);
+
+        read_lock(&conn->chan_lock);
+        c = __l2cap_get_chan_by_ident(conn, ident);
         if (c)
                 bh_lock_sock(c->sk);
-        read_unlock(&l->lock);
+        read_unlock(&conn->chan_lock);
         return c;
 }
 
-static u16 l2cap_alloc_cid(struct l2cap_chan_list *l)
+static u16 l2cap_alloc_cid(struct l2cap_conn *conn)
 {
         u16 cid = L2CAP_CID_DYN_START;
 
         for (; cid < L2CAP_CID_DYN_END; cid++) {
-                if (!__l2cap_get_chan_by_scid(l, cid))
+                if (!__l2cap_get_chan_by_scid(conn, cid))
                         return cid;
         }
 
@@ -153,38 +162,8 @@ static struct l2cap_chan *l2cap_chan_alloc(struct sock *sk)
         return chan;
 }
 
-static inline void __l2cap_chan_link(struct l2cap_chan_list *l, struct l2cap_chan *chan)
-{
-        sock_hold(chan->sk);
-
-        if (l->head)
-                l->head->prev_c = chan;
-
-        chan->next_c = l->head;
-        chan->prev_c = NULL;
-        l->head = chan;
-}
-
-static inline void l2cap_chan_unlink(struct l2cap_chan_list *l, struct l2cap_chan *chan)
-{
-        struct l2cap_chan *next = chan->next_c, *prev = chan->prev_c;
-
-        write_lock_bh(&l->lock);
-        if (chan == l->head)
-                l->head = next;
-
-        if (next)
-                next->prev_c = prev;
-        if (prev)
-                prev->next_c = next;
-        write_unlock_bh(&l->lock);
-
-        __sock_put(chan->sk);
-}
-
 static void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
 {
-        struct l2cap_chan_list *l = &conn->chan_list;
         struct sock *sk = chan->sk;
 
         BT_DBG("conn %p, psm 0x%2.2x, dcid 0x%4.4x", conn,
@@ -202,7 +181,7 @@ static void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
                         l2cap_pi(sk)->dcid = L2CAP_CID_LE_DATA;