Bluetooth: Only enable L2CAP FCS for ERTM or streaming

This fixes a bug which caused the FCS setting to show L2CAP_FCS_CRC16
with L2CAP modes other than ERTM or streaming.  At present, this only
affects the FCS value shown with getsockopt() for basic mode.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

1 files changed, 13 insertions, 6 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index fadf26b4ed7c..c7847035562b 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3071,6 +3071,17 @@ static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hd
         return 0;
 }
 
+static inline void set_default_fcs(struct l2cap_pinfo *pi)
+{
+        /* FCS is enabled only in ERTM or streaming mode, if one or both
+         * sides request it.
+         */
+        if (pi->mode != L2CAP_MODE_ERTM && pi->mode != L2CAP_MODE_STREAMING)
+                pi->fcs = L2CAP_FCS_NONE;
+        else if (!(pi->conf_state & L2CAP_CONF_NO_FCS_RECV))
+                pi->fcs = L2CAP_FCS_CRC16;
+}
+
 static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, u16 cmd_len, u8 *data)
 {
         struct l2cap_conf_req *req = (struct l2cap_conf_req *) data;
@@ -3135,9 +3146,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
                 goto unlock;
 
         if (l2cap_pi(sk)->conf_state & L2CAP_CONF_INPUT_DONE) {
-                if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_NO_FCS_RECV) ||
-                    l2cap_pi(sk)->fcs != L2CAP_FCS_NONE)
-                        l2cap_pi(sk)->fcs = L2CAP_FCS_CRC16;
+                set_default_fcs(l2cap_pi(sk));
 
                 sk->sk_state = BT_CONNECTED;
 
@@ -3225,9 +3234,7 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
         l2cap_pi(sk)->conf_state |= L2CAP_CONF_INPUT_DONE;
 
         if (l2cap_pi(sk)->conf_state & L2CAP_CONF_OUTPUT_DONE) {
-                if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_NO_FCS_RECV) ||
-                    l2cap_pi(sk)->fcs != L2CAP_FCS_NONE)
-                        l2cap_pi(sk)->fcs = L2CAP_FCS_CRC16;
+                set_default_fcs(l2cap_pi(sk));
 
                 sk->sk_state = BT_CONNECTED;
                 l2cap_pi(sk)->next_tx_seq = 0;