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From: Dongsheng Yang <dongsheng.yang@easystack.cn>
To: dan.j.williams@intel.com,
	axboe@kernel.dk
Cc: linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-cxl@vger.kernel.org,
	Dongsheng Yang <dongsheng.yang.linux@gmail.com>
Subject: [PATCH 7/7] cbd: add related sysfs files in transport register
Date: Mon, 22 Apr 2024 07:16:06 +0000
Message-Id: <20240422071606.52637-8-dongsheng.yang@easystack.cn>
In-Reply-To: <20240422071606.52637-1-dongsheng.yang@easystack.cn>
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From: Dongsheng Yang <dongsheng.yang.linux@gmail.com>

When a transport is registered, a corresponding file is created for each
area within the transport in the sysfs, including "cbd_hosts",
"cbd_backends", "cbd_blkdevs", and "cbd_channels".

Through these sysfs files, we can examine the information of each entity
and thereby understand the relationships between them. This allows us to
further understand the current operational status of the transport.

For example, by examining "cbd_hosts", we can find all the hosts
currently using the transport. We can also determine which host each
backend is running on by looking at the "host_id" in "cbd_backends".
Similarly, by examining "cbd_blkdevs", we can determine which host each
blkdev is running on, and through the "mapped_id", we can know the name
of the cbd device to which the blkdev is mapped. Additionally, by
looking at "cbd_channels", we can determine which blkdev and backend are
connected through each channel by examining the "blkdev_id" and
"backend_id".

Signed-off-by: Dongsheng Yang <dongsheng.yang.linux@gmail.com>
---
 drivers/block/cbd/cbd_transport.c | 101 +++++++++++++++++++++++++++++-
 1 file changed, 100 insertions(+), 1 deletion(-)

diff --git a/drivers/block/cbd/cbd_transport.c b/drivers/block/cbd/cbd_transport.c
index 75b9d34218fc..0e917d72b209 100644
--- a/drivers/block/cbd/cbd_transport.c
+++ b/drivers/block/cbd/cbd_transport.c
@@ -1,8 +1,91 @@
 #include <linux/pfn_t.h>
-
 #include "cbd_internal.h"
 
 #define CBDT_OBJ(OBJ, OBJ_SIZE)							\
+extern struct device_type cbd_##OBJ##_type;					\
+extern struct device_type cbd_##OBJ##s_type;					\
+										\
+static int cbd_##OBJ##s_init(struct cbd_transport *cbdt) 			\
+{ 										\
+	struct cbd_##OBJ##s_device *devs; 					\
+	struct cbd_##OBJ##_device *cbd_dev;					\
+	struct device *dev;							\
+	int i; 									\
+	int ret;								\
+										\
+	u32 memsize = struct_size(devs, OBJ##_devs,				\
+			cbdt->transport_info->OBJ##_num);			\
+	devs = kzalloc(memsize, GFP_KERNEL);					\
+	if (!devs) {								\
+	    return -ENOMEM;							\
+	}									\
+										\
+	dev = &devs->OBJ##s_dev;						\
+	device_initialize(dev);							\
+	device_set_pm_not_required(dev);					\
+	dev_set_name(dev, "cbd_" #OBJ "s");					\
+	dev->parent = &cbdt->device;						\
+	dev->type = &cbd_##OBJ##s_type;						\
+	ret = device_add(dev);							\
+	if (ret) {								\
+		goto devs_free;							\
+	}									\
+										\
+	for (i = 0; i < cbdt->transport_info->OBJ##_num; i++) {			\
+		cbd_dev = &devs->OBJ##_devs[i];					\
+		dev = &cbd_dev->dev;						\
+										\
+		cbd_dev->cbdt = cbdt;						\
+		cbd_dev->OBJ##_info = cbdt_get_##OBJ##_info(cbdt, i);		\
+		device_initialize(dev);						\
+		device_set_pm_not_required(dev);				\
+		dev_set_name(dev, #OBJ "%u", i);				\
+		dev->parent = &devs->OBJ##s_dev;				\
+		dev->type = &cbd_##OBJ##_type;					\
+										\
+		ret = device_add(dev);						\
+		if (ret) {							\
+			i--;							\
+			goto del_device;					\
+		}								\
+	}									\
+	cbdt->cbd_##OBJ##s_dev = devs;						\
+										\
+    	return 0;								\
+del_device:									\
+	for (; i >= 0; i--) {							\
+		cbd_dev = &devs->OBJ##_devs[i];					\
+		dev = &cbd_dev->dev;						\
+		device_del(dev);						\
+	}									\
+devs_free:									\
+	kfree(devs);								\
+	return ret;								\
+}										\
+										\
+static void cbd_##OBJ##s_exit(struct cbd_transport *cbdt)			\
+{										\
+	struct cbd_##OBJ##s_device *devs = cbdt->cbd_##OBJ##s_dev;		\
+	struct device *dev;							\
+	int i;									\
+										\
+	if (!devs)								\
+		return;								\
+										\
+	for (i = 0; i < cbdt->transport_info->OBJ##_num; i++) {			\
+		struct cbd_##OBJ##_device *cbd_dev = &devs->OBJ##_devs[i];	\
+		dev = &cbd_dev->dev;						\
+										\
+		device_del(dev);						\
+	}									\
+										\
+	device_del(&devs->OBJ##s_dev);						\
+										\
+	kfree(devs);								\
+	cbdt->cbd_##OBJ##s_dev = NULL;						\
+										\
+	return;									\
+}										\
 										\
 static inline struct cbd_##OBJ##_info						\
 *__get_##OBJ##_info(struct cbd_transport *cbdt, u32 id)				\
@@ -588,6 +671,11 @@ int cbdt_unregister(u32 tid)
 	}
 	mutex_unlock(&cbdt->lock);
 
+	cbd_blkdevs_exit(cbdt);
+	cbd_channels_exit(cbdt);
+	cbd_backends_exit(cbdt);
+	cbd_hosts_exit(cbdt);
+
 	cbd_host_unregister(cbdt);
 	device_unregister(&cbdt->device);
 	cbdt_dax_release(cbdt);
@@ -647,9 +735,20 @@ int cbdt_register(struct cbdt_register_options *opts)
 		goto dev_unregister;
 	}
 
+	if (cbd_hosts_init(cbdt) || cbd_backends_init(cbdt) ||
+	    cbd_channels_init(cbdt) || cbd_blkdevs_init(cbdt)) {
+		ret = -ENOMEM;
+		goto devs_exit;
+	}
+
 	return 0;
 
 devs_exit:
+	cbd_blkdevs_exit(cbdt);
+	cbd_channels_exit(cbdt);
+	cbd_backends_exit(cbdt);
+	cbd_hosts_exit(cbdt);
+
 	cbd_host_unregister(cbdt);
 dev_unregister:
 	device_unregister(&cbdt->device);
-- 
2.34.1