RDMA/core: Add Completion Counters support

Add core infrastructure for Completion Counters, a light-weight
alternative to polling CQ for tracking operation completions.

Define the UVERBS_OBJECT_COMP_CNTR ioctl object with create, destroy,
modify and read methods for both success and error counters. Add a QP
attach method on the QP object to associate a completion counter with a
queue pair.

Add ib_comp_cntr struct, ib_comp_cntr_attach_attr, device ops, and
DECLARE_RDMA_OBJ_SIZE for driver object allocation.

Only userspace Completion Counters are supported at this stage.

Reviewed-by: Yonatan Nachum <ynachum@amazon.com>
Signed-off-by: Michael Margolin <mrgolin@amazon.com>
Link: https://patch.msgid.link/20260722083603.30334-2-mrgolin@amazon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

2 files changed, 55 insertions, 0 deletions

diff --git a/include/uapi/rdma/ib_user_ioctl_cmds.h b/include/uapi/rdma/ib_user_ioctl_cmds.h
index 839835bd4b23..19a94b91987e 100644
--- a/include/uapi/rdma/ib_user_ioctl_cmds.h
+++ b/include/uapi/rdma/ib_user_ioctl_cmds.h
@@ -57,6 +57,7 @@ enum uverbs_default_objects {
 	UVERBS_OBJECT_ASYNC_EVENT,
 	UVERBS_OBJECT_DMAH,
 	UVERBS_OBJECT_DMABUF,
+	UVERBS_OBJECT_COMP_CNTR,
 };
 
 enum {
@@ -169,9 +170,16 @@ enum uverbs_attrs_destroy_qp_cmd_attr_ids {
 	UVERBS_ATTR_DESTROY_QP_RESP,
 };
 
+enum uverbs_attrs_qp_attach_comp_cntr_cmd_attr_ids {
+	UVERBS_ATTR_QP_ATTACH_COMP_CNTR_HANDLE,
+	UVERBS_ATTR_QP_ATTACH_COMP_CNTR_CNTR_HANDLE,
+	UVERBS_ATTR_QP_ATTACH_COMP_CNTR_OP_MASK,
+};
+
 enum uverbs_methods_qp {
 	UVERBS_METHOD_QP_CREATE,
 	UVERBS_METHOD_QP_DESTROY,
+	UVERBS_METHOD_QP_ATTACH_COMP_CNTR,
 };
 
 enum uverbs_attrs_create_srq_cmd_attr_ids {
@@ -438,4 +446,32 @@ enum uverbs_attrs_query_gid_entry_cmd_attr_ids {
 	UVERBS_ATTR_QUERY_GID_ENTRY_RESP_ENTRY,
 };
 
+enum uverbs_methods_comp_cntr {
+	UVERBS_METHOD_COMP_CNTR_CREATE,
+	UVERBS_METHOD_COMP_CNTR_DESTROY,
+	UVERBS_METHOD_COMP_CNTR_MODIFY,
+	UVERBS_METHOD_COMP_CNTR_READ,
+};
+
+enum uverbs_attrs_create_comp_cntr_cmd_attr_ids {
+	UVERBS_ATTR_CREATE_COMP_CNTR_HANDLE,
+};
+
+enum uverbs_attrs_destroy_comp_cntr_cmd_attr_ids {
+	UVERBS_ATTR_DESTROY_COMP_CNTR_HANDLE,
+};
+
+enum uverbs_attrs_modify_comp_cntr_cmd_attr_ids {
+	UVERBS_ATTR_MODIFY_COMP_CNTR_HANDLE,
+	UVERBS_ATTR_MODIFY_COMP_CNTR_ENTRY,
+	UVERBS_ATTR_MODIFY_COMP_CNTR_OP,
+	UVERBS_ATTR_MODIFY_COMP_CNTR_VALUE,
+};
+
+enum uverbs_attrs_read_comp_cntr_cmd_attr_ids {
+	UVERBS_ATTR_READ_COMP_CNTR_HANDLE,
+	UVERBS_ATTR_READ_COMP_CNTR_ENTRY,
+	UVERBS_ATTR_READ_COMP_CNTR_RESP_VALUE,
+};
+
 #endif
diff --git a/include/uapi/rdma/ib_user_ioctl_verbs.h b/include/uapi/rdma/ib_user_ioctl_verbs.h
index 51030c27d479..21f86cc7bb1f 100644
--- a/include/uapi/rdma/ib_user_ioctl_verbs.h
+++ b/include/uapi/rdma/ib_user_ioctl_verbs.h
@@ -300,4 +300,23 @@ struct ib_uverbs_buffer_desc {
 	__aligned_u64 length;
 };
 
+enum ib_uverbs_comp_cntr_entry {
+	IB_UVERBS_COMP_CNTR_ENTRY_COMP,
+	IB_UVERBS_COMP_CNTR_ENTRY_ERR,
+};
+
+enum ib_uverbs_comp_cntr_modify_op {
+	IB_UVERBS_COMP_CNTR_MODIFY_OP_SET,
+	IB_UVERBS_COMP_CNTR_MODIFY_OP_INC,
+};
+
+enum ib_uverbs_qp_attach_comp_cntr_op {
+	IB_UVERBS_QP_ATTACH_COMP_CNTR_OP_SEND = 1 << 0,
+	IB_UVERBS_QP_ATTACH_COMP_CNTR_OP_RECV = 1 << 1,
+	IB_UVERBS_QP_ATTACH_COMP_CNTR_OP_RDMA_READ = 1 << 2,
+	IB_UVERBS_QP_ATTACH_COMP_CNTR_OP_REMOTE_RDMA_READ = 1 << 3,
+	IB_UVERBS_QP_ATTACH_COMP_CNTR_OP_RDMA_WRITE = 1 << 4,
+	IB_UVERBS_QP_ATTACH_COMP_CNTR_OP_REMOTE_RDMA_WRITE = 1 << 5,
+};
+
 #endif