fs/zonefs/sysfs.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Simple file system for zoned block devices exposing zones as files.
0004  *
0005  * Copyright (C) 2022 Western Digital Corporation or its affiliates.
0006  */
0007 #include <linux/fs.h>
0008 #include <linux/seq_file.h>
0009 #include <linux/blkdev.h>
0010
0011 #include "zonefs.h"
0012
0013 struct zonefs_sysfs_attr {
0014     struct attribute attr;
0015     ssize_t (*show)(struct zonefs_sb_info *sbi, char *buf);
0016 };
0017
0018 static inline struct zonefs_sysfs_attr *to_attr(struct attribute *attr)
0019 {
0020     return container_of(attr, struct zonefs_sysfs_attr, attr);
0021 }
0022
0023 #define ZONEFS_SYSFS_ATTR_RO(name) \
0024 static struct zonefs_sysfs_attr zonefs_sysfs_attr_##name = __ATTR_RO(name)
0025
0026 #define ATTR_LIST(name) &zonefs_sysfs_attr_##name.attr
0027
0028 static ssize_t zonefs_sysfs_attr_show(struct kobject *kobj,
0029                       struct attribute *attr, char *buf)
0030 {
0031     struct zonefs_sb_info *sbi =
0032         container_of(kobj, struct zonefs_sb_info, s_kobj);
0033     struct zonefs_sysfs_attr *zonefs_attr =
0034         container_of(attr, struct zonefs_sysfs_attr, attr);
0035
0036     if (!zonefs_attr->show)
0037         return 0;
0038
0039     return zonefs_attr->show(sbi, buf);
0040 }
0041
0042 static ssize_t max_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
0043 {
0044     return sysfs_emit(buf, "%u\n", sbi->s_max_wro_seq_files);
0045 }
0046 ZONEFS_SYSFS_ATTR_RO(max_wro_seq_files);
0047
0048 static ssize_t nr_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
0049 {
0050     return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_wro_seq_files));
0051 }
0052 ZONEFS_SYSFS_ATTR_RO(nr_wro_seq_files);
0053
0054 static ssize_t max_active_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
0055 {
0056     return sysfs_emit(buf, "%u\n", sbi->s_max_active_seq_files);
0057 }
0058 ZONEFS_SYSFS_ATTR_RO(max_active_seq_files);
0059
0060 static ssize_t nr_active_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
0061 {
0062     return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_active_seq_files));
0063 }
0064 ZONEFS_SYSFS_ATTR_RO(nr_active_seq_files);
0065
0066 static struct attribute *zonefs_sysfs_attrs[] = {
0067     ATTR_LIST(max_wro_seq_files),
0068     ATTR_LIST(nr_wro_seq_files),
0069     ATTR_LIST(max_active_seq_files),
0070     ATTR_LIST(nr_active_seq_files),
0071     NULL,
0072 };
0073 ATTRIBUTE_GROUPS(zonefs_sysfs);
0074
0075 static void zonefs_sysfs_sb_release(struct kobject *kobj)
0076 {
0077     struct zonefs_sb_info *sbi =
0078         container_of(kobj, struct zonefs_sb_info, s_kobj);
0079
0080     complete(&sbi->s_kobj_unregister);
0081 }
0082
0083 static const struct sysfs_ops zonefs_sysfs_attr_ops = {
0084     .show   = zonefs_sysfs_attr_show,
0085 };
0086
0087 static struct kobj_type zonefs_sb_ktype = {
0088     .default_groups = zonefs_sysfs_groups,
0089     .sysfs_ops  = &zonefs_sysfs_attr_ops,
0090     .release    = zonefs_sysfs_sb_release,
0091 };
0092
0093 static struct kobject *zonefs_sysfs_root;
0094
0095 int zonefs_sysfs_register(struct super_block *sb)
0096 {
0097     struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
0098     int ret;
0099
0100     init_completion(&sbi->s_kobj_unregister);
0101     ret = kobject_init_and_add(&sbi->s_kobj, &zonefs_sb_ktype,
0102                    zonefs_sysfs_root, "%s", sb->s_id);
0103     if (ret) {
0104         kobject_put(&sbi->s_kobj);
0105         wait_for_completion(&sbi->s_kobj_unregister);
0106         return ret;
0107     }
0108
0109     sbi->s_sysfs_registered = true;
0110
0111     return 0;
0112 }
0113
0114 void zonefs_sysfs_unregister(struct super_block *sb)
0115 {
0116     struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
0117
0118     if (!sbi || !sbi->s_sysfs_registered)
0119         return;
0120
0121     kobject_del(&sbi->s_kobj);
0122     kobject_put(&sbi->s_kobj);
0123     wait_for_completion(&sbi->s_kobj_unregister);
0124 }
0125
0126 int __init zonefs_sysfs_init(void)
0127 {
0128     zonefs_sysfs_root = kobject_create_and_add("zonefs", fs_kobj);
0129     if (!zonefs_sysfs_root)
0130         return -ENOMEM;
0131
0132     return 0;
0133 }
0134
0135 void zonefs_sysfs_exit(void)
0136 {
0137     kobject_put(zonefs_sysfs_root);
0138     zonefs_sysfs_root = NULL;
0139 }