xref: /kernel/linux/linux-6.6/fs/zonefs/sysfs.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Simple file system for zoned block devices exposing zones as files.
4 *
5 * Copyright (C) 2022 Western Digital Corporation or its affiliates.
6 */
7#include <linux/fs.h>
8#include <linux/seq_file.h>
9#include <linux/blkdev.h>
10
11#include "zonefs.h"
12
13struct zonefs_sysfs_attr {
14	struct attribute attr;
15	ssize_t (*show)(struct zonefs_sb_info *sbi, char *buf);
16};
17
18#define ZONEFS_SYSFS_ATTR_RO(name) \
19static struct zonefs_sysfs_attr zonefs_sysfs_attr_##name = __ATTR_RO(name)
20
21#define ATTR_LIST(name) &zonefs_sysfs_attr_##name.attr
22
23static ssize_t zonefs_sysfs_attr_show(struct kobject *kobj,
24				      struct attribute *attr, char *buf)
25{
26	struct zonefs_sb_info *sbi =
27		container_of(kobj, struct zonefs_sb_info, s_kobj);
28	struct zonefs_sysfs_attr *zonefs_attr =
29		container_of(attr, struct zonefs_sysfs_attr, attr);
30
31	if (!zonefs_attr->show)
32		return 0;
33
34	return zonefs_attr->show(sbi, buf);
35}
36
37static ssize_t max_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
38{
39	return sysfs_emit(buf, "%u\n", sbi->s_max_wro_seq_files);
40}
41ZONEFS_SYSFS_ATTR_RO(max_wro_seq_files);
42
43static ssize_t nr_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
44{
45	return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_wro_seq_files));
46}
47ZONEFS_SYSFS_ATTR_RO(nr_wro_seq_files);
48
49static ssize_t max_active_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
50{
51	return sysfs_emit(buf, "%u\n", sbi->s_max_active_seq_files);
52}
53ZONEFS_SYSFS_ATTR_RO(max_active_seq_files);
54
55static ssize_t nr_active_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
56{
57	return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_active_seq_files));
58}
59ZONEFS_SYSFS_ATTR_RO(nr_active_seq_files);
60
61static struct attribute *zonefs_sysfs_attrs[] = {
62	ATTR_LIST(max_wro_seq_files),
63	ATTR_LIST(nr_wro_seq_files),
64	ATTR_LIST(max_active_seq_files),
65	ATTR_LIST(nr_active_seq_files),
66	NULL,
67};
68ATTRIBUTE_GROUPS(zonefs_sysfs);
69
70static void zonefs_sysfs_sb_release(struct kobject *kobj)
71{
72	struct zonefs_sb_info *sbi =
73		container_of(kobj, struct zonefs_sb_info, s_kobj);
74
75	complete(&sbi->s_kobj_unregister);
76}
77
78static const struct sysfs_ops zonefs_sysfs_attr_ops = {
79	.show	= zonefs_sysfs_attr_show,
80};
81
82static const struct kobj_type zonefs_sb_ktype = {
83	.default_groups = zonefs_sysfs_groups,
84	.sysfs_ops	= &zonefs_sysfs_attr_ops,
85	.release	= zonefs_sysfs_sb_release,
86};
87
88static struct kobject *zonefs_sysfs_root;
89
90int zonefs_sysfs_register(struct super_block *sb)
91{
92	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
93	int ret;
94
95	init_completion(&sbi->s_kobj_unregister);
96	ret = kobject_init_and_add(&sbi->s_kobj, &zonefs_sb_ktype,
97				   zonefs_sysfs_root, "%s", sb->s_id);
98	if (ret) {
99		kobject_put(&sbi->s_kobj);
100		wait_for_completion(&sbi->s_kobj_unregister);
101		return ret;
102	}
103
104	sbi->s_sysfs_registered = true;
105
106	return 0;
107}
108
109void zonefs_sysfs_unregister(struct super_block *sb)
110{
111	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
112
113	if (!sbi || !sbi->s_sysfs_registered)
114		return;
115
116	kobject_del(&sbi->s_kobj);
117	kobject_put(&sbi->s_kobj);
118	wait_for_completion(&sbi->s_kobj_unregister);
119}
120
121int __init zonefs_sysfs_init(void)
122{
123	zonefs_sysfs_root = kobject_create_and_add("zonefs", fs_kobj);
124	if (!zonefs_sysfs_root)
125		return -ENOMEM;
126
127	return 0;
128}
129
130void zonefs_sysfs_exit(void)
131{
132	kobject_put(zonefs_sysfs_root);
133	zonefs_sysfs_root = NULL;
134}
135