From: Raed Salem <raeds@mellanox.com>
Date: Thu, 31 May 2018 16:43:34 +0300
Subject: IB/uverbs: Add read counters support
Patch-mainline: v4.18-rc1
Git-commit: ebb6796bd397f3fb9b2b46398b2fbb585e1b8bb6
References: bsc#1103992 FATE#326009

This patch exposes the read counters verb to user space applications.  By
that verb the user can read the hardware counters which are associated
with the counters object.

The application needs to provide a sufficient memory to hold the
statistics.

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Raed Salem <raeds@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/uverbs_std_types_counters.c |   59 +++++++++++++++++++-
 include/uapi/rdma/ib_user_ioctl_cmds.h              |    7 ++
 2 files changed, 65 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/uverbs_std_types_counters.c
+++ b/drivers/infiniband/core/uverbs_std_types_counters.c
@@ -80,6 +80,49 @@ err_create_counters:
 	return ret;
 }
 
+static int UVERBS_HANDLER(UVERBS_METHOD_COUNTERS_READ)(struct ib_device *ib_dev,
+						       struct ib_uverbs_file *file,
+						       struct uverbs_attr_bundle *attrs)
+{
+	struct ib_counters_read_attr read_attr = {};
+	const struct uverbs_attr *uattr;
+	struct ib_counters *counters =
+		uverbs_attr_get_obj(attrs, UVERBS_ATTR_READ_COUNTERS_HANDLE);
+	int ret;
+
+	if (!ib_dev->read_counters)
+		return -EOPNOTSUPP;
+
+	if (!atomic_read(&counters->usecnt))
+		return -EINVAL;
+
+	ret = uverbs_copy_from(&read_attr.flags, attrs,
+			       UVERBS_ATTR_READ_COUNTERS_FLAGS);
+	if (ret)
+		return ret;
+
+	uattr = uverbs_attr_get(attrs, UVERBS_ATTR_READ_COUNTERS_BUFF);
+	read_attr.ncounters = uattr->ptr_attr.len / sizeof(u64);
+	read_attr.counters_buff = kcalloc(read_attr.ncounters,
+					  sizeof(u64), GFP_KERNEL);
+	if (!read_attr.counters_buff)
+		return -ENOMEM;
+
+	ret = ib_dev->read_counters(counters,
+				    &read_attr,
+				    attrs);
+	if (ret)
+		goto err_read;
+
+	ret = uverbs_copy_to(attrs, UVERBS_ATTR_READ_COUNTERS_BUFF,
+			     read_attr.counters_buff,
+			     read_attr.ncounters * sizeof(u64));
+
+err_read:
+	kfree(read_attr.counters_buff);
+	return ret;
+}
+
 static DECLARE_UVERBS_NAMED_METHOD(UVERBS_METHOD_COUNTERS_CREATE,
 	&UVERBS_ATTR_IDR(UVERBS_ATTR_CREATE_COUNTERS_HANDLE,
 			 UVERBS_OBJECT_COUNTERS,
@@ -93,8 +136,22 @@ static DECLARE_UVERBS_NAMED_METHOD_WITH_
 			 UVERBS_ACCESS_DESTROY,
 			 UA_FLAGS(UVERBS_ATTR_SPEC_F_MANDATORY)));
 
+#define MAX_COUNTERS_BUFF_SIZE USHRT_MAX
+static DECLARE_UVERBS_NAMED_METHOD(UVERBS_METHOD_COUNTERS_READ,
+	&UVERBS_ATTR_IDR(UVERBS_ATTR_READ_COUNTERS_HANDLE,
+			 UVERBS_OBJECT_COUNTERS,
+			 UVERBS_ACCESS_READ,
+			 UA_FLAGS(UVERBS_ATTR_SPEC_F_MANDATORY)),
+	&UVERBS_ATTR_PTR_OUT(UVERBS_ATTR_READ_COUNTERS_BUFF,
+			     UVERBS_ATTR_SIZE(0, MAX_COUNTERS_BUFF_SIZE),
+			     UA_FLAGS(UVERBS_ATTR_SPEC_F_MANDATORY)),
+	&UVERBS_ATTR_PTR_IN(UVERBS_ATTR_READ_COUNTERS_FLAGS,
+			    UVERBS_ATTR_TYPE(__u32),
+			    UA_FLAGS(UVERBS_ATTR_SPEC_F_MANDATORY)));
+
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_COUNTERS,
 			    &UVERBS_TYPE_ALLOC_IDR(0, uverbs_free_counters),
 			    &UVERBS_METHOD(UVERBS_METHOD_COUNTERS_CREATE),
-			    &UVERBS_METHOD(UVERBS_METHOD_COUNTERS_DESTROY));
+			    &UVERBS_METHOD(UVERBS_METHOD_COUNTERS_DESTROY),
+			    &UVERBS_METHOD(UVERBS_METHOD_COUNTERS_READ));
 
--- a/include/uapi/rdma/ib_user_ioctl_cmds.h
+++ b/include/uapi/rdma/ib_user_ioctl_cmds.h
@@ -140,9 +140,16 @@ enum uverbs_attrs_destroy_counters_cmd_a
 	UVERBS_ATTR_DESTROY_COUNTERS_HANDLE,
 };
 
+enum uverbs_attrs_read_counters_cmd_attr_ids {
+	UVERBS_ATTR_READ_COUNTERS_HANDLE,
+	UVERBS_ATTR_READ_COUNTERS_BUFF,
+	UVERBS_ATTR_READ_COUNTERS_FLAGS,
+};
+
 enum uverbs_methods_actions_counters_ops {
 	UVERBS_METHOD_COUNTERS_CREATE,
 	UVERBS_METHOD_COUNTERS_DESTROY,
+	UVERBS_METHOD_COUNTERS_READ,
 };
 
 #endif