IB/uverbs: Expose RSS related capabilities

Query RSS related attributes and return them to user-space via the
extended query device uverbs command.

It includes both direct ones (i.e. struct ib_uverbs_rss_caps) and
max_wq_type_rq which may be used in both RSS and non RSS flows.
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -4173,6 +4173,23 @@ int ib_uverbs_ex_query_device(struct ib_uverbs_file *file,
 
 	resp.device_cap_flags_ex = attr.device_cap_flags;
 	resp.response_length += sizeof(resp.device_cap_flags_ex);
+
+	if (ucore->outlen < resp.response_length + sizeof(resp.rss_caps))
+		goto end;
+
+	resp.rss_caps.supported_qpts = attr.rss_caps.supported_qpts;
+	resp.rss_caps.max_rwq_indirection_tables =
+		attr.rss_caps.max_rwq_indirection_tables;
+	resp.rss_caps.max_rwq_indirection_table_size =
+		attr.rss_caps.max_rwq_indirection_table_size;
+
+	resp.response_length += sizeof(resp.rss_caps);
+
+	if (ucore->outlen < resp.response_length + sizeof(resp.max_wq_type_rq))
+		goto end;
+
+	resp.max_wq_type_rq = attr.max_wq_type_rq;
+	resp.response_length += sizeof(resp.max_wq_type_rq);
 end:
 	err = ib_copy_to_udata(ucore, &resp, resp.response_length);
 	return err;

include/uapi/rdma/ib_user_verbs.h

@@ -224,6 +224,17 @@ struct ib_uverbs_odp_caps {
 	__u32 reserved;
 };
 
+struct ib_uverbs_rss_caps {
+	/* Corresponding bit will be set if qp type from
+	 * 'enum ib_qp_type' is supported, e.g.
+	 * supported_qpts |= 1 << IB_QPT_UD
+	 */
+	__u32 supported_qpts;
+	__u32 max_rwq_indirection_tables;
+	__u32 max_rwq_indirection_table_size;
+	__u32 reserved;
+};
+
 struct ib_uverbs_ex_query_device_resp {
 	struct ib_uverbs_query_device_resp base;
 	__u32 comp_mask;
@@ -232,6 +243,9 @@ struct ib_uverbs_ex_query_device_resp {
 	__u64 timestamp_mask;
 	__u64 hca_core_clock; /* in KHZ */
 	__u64 device_cap_flags_ex;
+	struct ib_uverbs_rss_caps rss_caps;
+	__u32  max_wq_type_rq;
+	__u32 reserved;
 };
 
 struct ib_uverbs_query_port {