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
13 struct 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) \
19 static struct zonefs_sysfs_attr zonefs_sysfs_attr_##name = __ATTR_RO(name)
20
21 #define ATTR_LIST(name) &zonefs_sysfs_attr_##name.attr
22
23 static 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
37 static 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 }
41 ZONEFS_SYSFS_ATTR_RO(max_wro_seq_files);
42
43 static 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 }
47 ZONEFS_SYSFS_ATTR_RO(nr_wro_seq_files);
48
49 static 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 }
53 ZONEFS_SYSFS_ATTR_RO(max_active_seq_files);
54
55 static 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 }
59 ZONEFS_SYSFS_ATTR_RO(nr_active_seq_files);
60
61 static 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 };
68 ATTRIBUTE_GROUPS(zonefs_sysfs);
69
70 static 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
78 static const struct sysfs_ops zonefs_sysfs_attr_ops = {
79 .show = zonefs_sysfs_attr_show,
80 };
81
82 static 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
88 static struct kobject *zonefs_sysfs_root;
89
90 int 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
109 void 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
121 int __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
130 void zonefs_sysfs_exit(void)
131 {
132 kobject_put(zonefs_sysfs_root);
133 zonefs_sysfs_root = NULL;
134 }
135
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