IB/uverbs: Add CQ moderation capability to query_device

The query_device function can now obtain the maximum values for
cq_max_count and cq_period, needed for CQ moderation.
cq_max_count is a 16 bits number that determines the number
of CQEs to accumulate before generating an event.
cq_period is a 16 bits number that determines the timeout in micro
seconds from the last event generated, upon which a new event will
be generated even if cq_max_count was not reached.

Signed-off-by: Yonatan Cohen <yonatanc@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -3852,6 +3852,15 @@ int ib_uverbs_ex_query_device(struct ib_uverbs_file *file,
 	resp.tm_caps.max_sge		= attr.tm_caps.max_sge;
 	resp.tm_caps.flags		= attr.tm_caps.flags;
 	resp.response_length += sizeof(resp.tm_caps);
+
+	if (ucore->outlen < resp.response_length + sizeof(resp.cq_moderation_caps))
+		goto end;
+
+	resp.cq_moderation_caps.max_cq_moderation_count  =
+		attr.cq_caps.max_cq_moderation_count;
+	resp.cq_moderation_caps.max_cq_moderation_period =
+		attr.cq_caps.max_cq_moderation_period;
+	resp.response_length += sizeof(resp.cq_moderation_caps);
 end:
 	err = ib_copy_to_udata(ucore, &resp, resp.response_length);
 	return err;

include/rdma/ib_verbs.h

@@ -315,6 +315,11 @@ enum ib_cq_attr_mask {
 	IB_CQ_MODERATE = 1 << 0,
 };
 
+struct ib_cq_caps {
+	u16     max_cq_moderation_count;
+	u16     max_cq_moderation_period;
+};
+
 struct ib_device_attr {
 	u64			fw_ver;
 	__be64			sys_image_guid;
@@ -365,6 +370,7 @@ struct ib_device_attr {
 	u32			max_wq_type_rq;
 	u32			raw_packet_caps; /* Use ib_raw_packet_caps enum */
 	struct ib_tm_caps	tm_caps;
+	struct ib_cq_caps       cq_caps;
 };
 
 enum ib_mtu {

include/uapi/rdma/ib_user_verbs.h

@@ -125,6 +125,12 @@ struct ib_uverbs_comp_event_desc {
 	__u64 cq_handle;
 };
 
+struct ib_uverbs_cq_moderation_caps {
+	__u16     max_cq_moderation_count;
+	__u16     max_cq_moderation_period;
+	__u32     reserved;
+};
+
 /*
  * All commands from userspace should start with a __u32 command field
  * followed by __u16 in_words and out_words fields (which give the
@@ -263,6 +269,7 @@ struct ib_uverbs_ex_query_device_resp {
 	__u32  max_wq_type_rq;
 	__u32 raw_packet_caps;
 	struct ib_uverbs_tm_caps tm_caps;
+	struct ib_uverbs_cq_moderation_caps cq_moderation_caps;
 };
 
 struct ib_uverbs_query_port {