IB/sa: Track multicast join/leave requests

The IB SA tracks multicast join/leave requests on a per port basis and
does not do any reference counting: if two users of the same port join
the same group, and one leaves that group, then the SA will remove the
port from the group even though there is one user who wants to stay a
member left.  Therefore, in order to support multiple users of the
same multicast group from the same port, we need to perform reference
counting locally.

To do this, add an multicast submodule to ib_sa to perform reference
counting of multicast join/leave operations.  Modify ib_ipoib (the
only in-kernel user of multicast) to use the new interface.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/drivers/infiniband/core/sa.h b/drivers/infiniband/core/sa.h
new file mode 100644
index 000000000000..24c93fd320fb
--- /dev/null
+++ b/drivers/infiniband/core/sa.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2004 Topspin Communications.  All rights reserved.
+ * Copyright (c) 2005 Voltaire, Inc.  All rights reserved.
+ * Copyright (c) 2006 Intel Corporation.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef SA_H
+#define SA_H
+
+#include <rdma/ib_sa.h>
+
+static inline void ib_sa_client_get(struct ib_sa_client *client)
+{
+        atomic_inc(&client->users);
+}
+
+static inline void ib_sa_client_put(struct ib_sa_client *client)
+{
+        if (atomic_dec_and_test(&client->users))
+                complete(&client->comp);
+}
+
+int ib_sa_mcmember_rec_query(struct ib_sa_client *client,
+                             struct ib_device *device, u8 port_num,
+                             u8 method,
+                             struct ib_sa_mcmember_rec *rec,
+                             ib_sa_comp_mask comp_mask,
+                             int timeout_ms, gfp_t gfp_mask,
+                             void (*callback)(int status,
+                                              struct ib_sa_mcmember_rec *resp,
+                                              void *context),
+                             void *context,
+                             struct ib_sa_query **sa_query);
+
+int mcast_init(void);
+void mcast_cleanup(void);
+
+#endif /* SA_H */