Bluetooth: Host: Fix use of local variable as atomic target

In bt_conn_unref(), a local variable is used as atomic target:

    atomic_val_t old = atomic_dec(&conn->ref);
    /* Prevent from accessing connection object */
    bool deallocated = (atomic_get(&old) == 1);

Using atomic_get() to access a non-shared local variable
cannot prevent any data race on that variable,
and only causes confusion.

Moreover, this call to atomic_get() is incorrect: the API expects
an atomic_t* argument (target), not an atomic_val_t* (value).
This compiles and /works/ only because Zephyr defines both to be
the same integer type, and thus: atomic_get(&old) == old.
The equivalent C11 code, where _Atomic(T) and T are different types,
wouldn't compile.

Signed-off-by: Christophe Dufaza <[email protected]>

Author: dottspina

subsys/bluetooth/host/conn.c

@@ -1511,8 +1511,8 @@ void bt_conn_unref(struct bt_conn *conn)
 	conn_handle = conn->handle;
 
 	old = atomic_dec(&conn->ref);
-	/* Prevent from accessing connection object */
-	deallocated = (atomic_get(&old) == 1);
+	/* Whether we removed the last reference. */
+	deallocated = (old == 1);
 	IF_ENABLED(CONFIG_BT_CONN_TX,
 		   (__ASSERT(!(deallocated && k_work_is_pending(&conn->tx_complete_work)),
 			     "tx_complete_work is pending when conn is deallocated")));