cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sysfs.c (3449B)

      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
     18static inline struct zonefs_sysfs_attr *to_attr(struct attribute *attr)
     19{
     20	return container_of(attr, struct zonefs_sysfs_attr, attr);
     21}
     22
     23#define ZONEFS_SYSFS_ATTR_RO(name) \
     24static struct zonefs_sysfs_attr zonefs_sysfs_attr_##name = __ATTR_RO(name)
     25
     26#define ATTR_LIST(name) &zonefs_sysfs_attr_##name.attr
     27
     28static ssize_t zonefs_sysfs_attr_show(struct kobject *kobj,
     29				      struct attribute *attr, char *buf)
     30{
     31	struct zonefs_sb_info *sbi =
     32		container_of(kobj, struct zonefs_sb_info, s_kobj);
     33	struct zonefs_sysfs_attr *zonefs_attr =
     34		container_of(attr, struct zonefs_sysfs_attr, attr);
     35
     36	if (!zonefs_attr->show)
     37		return 0;
     38
     39	return zonefs_attr->show(sbi, buf);
     40}
     41
     42static ssize_t max_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
     43{
     44	return sysfs_emit(buf, "%u\n", sbi->s_max_wro_seq_files);
     45}
     46ZONEFS_SYSFS_ATTR_RO(max_wro_seq_files);
     47
     48static ssize_t nr_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
     49{
     50	return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_wro_seq_files));
     51}
     52ZONEFS_SYSFS_ATTR_RO(nr_wro_seq_files);
     53
     54static ssize_t max_active_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
     55{
     56	return sysfs_emit(buf, "%u\n", sbi->s_max_active_seq_files);
     57}
     58ZONEFS_SYSFS_ATTR_RO(max_active_seq_files);
     59
     60static ssize_t nr_active_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
     61{
     62	return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_active_seq_files));
     63}
     64ZONEFS_SYSFS_ATTR_RO(nr_active_seq_files);
     65
     66static struct attribute *zonefs_sysfs_attrs[] = {
     67	ATTR_LIST(max_wro_seq_files),
     68	ATTR_LIST(nr_wro_seq_files),
     69	ATTR_LIST(max_active_seq_files),
     70	ATTR_LIST(nr_active_seq_files),
     71	NULL,
     72};
     73ATTRIBUTE_GROUPS(zonefs_sysfs);
     74
     75static void zonefs_sysfs_sb_release(struct kobject *kobj)
     76{
     77	struct zonefs_sb_info *sbi =
     78		container_of(kobj, struct zonefs_sb_info, s_kobj);
     79
     80	complete(&sbi->s_kobj_unregister);
     81}
     82
     83static const struct sysfs_ops zonefs_sysfs_attr_ops = {
     84	.show	= zonefs_sysfs_attr_show,
     85};
     86
     87static struct kobj_type zonefs_sb_ktype = {
     88	.default_groups = zonefs_sysfs_groups,
     89	.sysfs_ops	= &zonefs_sysfs_attr_ops,
     90	.release	= zonefs_sysfs_sb_release,
     91};
     92
     93static struct kobject *zonefs_sysfs_root;
     94
     95int zonefs_sysfs_register(struct super_block *sb)
     96{
     97	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
     98	int ret;
     99
    100	init_completion(&sbi->s_kobj_unregister);
    101	ret = kobject_init_and_add(&sbi->s_kobj, &zonefs_sb_ktype,
    102				   zonefs_sysfs_root, "%s", sb->s_id);
    103	if (ret) {
    104		kobject_put(&sbi->s_kobj);
    105		wait_for_completion(&sbi->s_kobj_unregister);
    106		return ret;
    107	}
    108
    109	sbi->s_sysfs_registered = true;
    110
    111	return 0;
    112}
    113
    114void zonefs_sysfs_unregister(struct super_block *sb)
    115{
    116	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
    117
    118	if (!sbi || !sbi->s_sysfs_registered)
    119		return;
    120
    121	kobject_del(&sbi->s_kobj);
    122	kobject_put(&sbi->s_kobj);
    123	wait_for_completion(&sbi->s_kobj_unregister);
    124}
    125
    126int __init zonefs_sysfs_init(void)
    127{
    128	zonefs_sysfs_root = kobject_create_and_add("zonefs", fs_kobj);
    129	if (!zonefs_sysfs_root)
    130		return -ENOMEM;
    131
    132	return 0;
    133}
    134
    135void zonefs_sysfs_exit(void)
    136{
    137	kobject_put(zonefs_sysfs_root);
    138	zonefs_sysfs_root = NULL;
    139}