linux-stable/fs/openpromfs/inode.c
Vladimir Davydov 5d097056c9 kmemcg: account certain kmem allocations to memcg
Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14 16:00:49 -08:00

471 lines
9.6 KiB
C

/* inode.c: /proc/openprom handling routines
*
* Copyright (C) 1996-1999 Jakub Jelinek (jakub@redhat.com)
* Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/magic.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
static DEFINE_MUTEX(op_mutex);
#define OPENPROM_ROOT_INO 0
enum op_inode_type {
op_inode_node,
op_inode_prop,
};
union op_inode_data {
struct device_node *node;
struct property *prop;
};
struct op_inode_info {
struct inode vfs_inode;
enum op_inode_type type;
union op_inode_data u;
};
static struct inode *openprom_iget(struct super_block *sb, ino_t ino);
static inline struct op_inode_info *OP_I(struct inode *inode)
{
return container_of(inode, struct op_inode_info, vfs_inode);
}
static int is_string(unsigned char *p, int len)
{
int i;
for (i = 0; i < len; i++) {
unsigned char val = p[i];
if ((i && !val) ||
(val >= ' ' && val <= '~'))
continue;
return 0;
}
return 1;
}
static int property_show(struct seq_file *f, void *v)
{
struct property *prop = f->private;
void *pval;
int len;
len = prop->length;
pval = prop->value;
if (is_string(pval, len)) {
while (len > 0) {
int n = strlen(pval);
seq_printf(f, "%s", (char *) pval);
/* Skip over the NULL byte too. */
pval += n + 1;
len -= n + 1;
if (len > 0)
seq_printf(f, " + ");
}
} else {
if (len & 3) {
while (len) {
len--;
if (len)
seq_printf(f, "%02x.",
*(unsigned char *) pval);
else
seq_printf(f, "%02x",
*(unsigned char *) pval);
pval++;
}
} else {
while (len >= 4) {
len -= 4;
if (len)
seq_printf(f, "%08x.",
*(unsigned int *) pval);
else
seq_printf(f, "%08x",
*(unsigned int *) pval);
pval += 4;
}
}
}
seq_printf(f, "\n");
return 0;
}
static void *property_start(struct seq_file *f, loff_t *pos)
{
if (*pos == 0)
return pos;
return NULL;
}
static void *property_next(struct seq_file *f, void *v, loff_t *pos)
{
(*pos)++;
return NULL;
}
static void property_stop(struct seq_file *f, void *v)
{
/* Nothing to do */
}
static const struct seq_operations property_op = {
.start = property_start,
.next = property_next,
.stop = property_stop,
.show = property_show
};
static int property_open(struct inode *inode, struct file *file)
{
struct op_inode_info *oi = OP_I(inode);
int ret;
BUG_ON(oi->type != op_inode_prop);
ret = seq_open(file, &property_op);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = oi->u.prop;
}
return ret;
}
static const struct file_operations openpromfs_prop_ops = {
.open = property_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int openpromfs_readdir(struct file *, struct dir_context *);
static const struct file_operations openprom_operations = {
.read = generic_read_dir,
.iterate = openpromfs_readdir,
.llseek = generic_file_llseek,
};
static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, unsigned int);
static const struct inode_operations openprom_inode_operations = {
.lookup = openpromfs_lookup,
};
static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
struct op_inode_info *ent_oi, *oi = OP_I(dir);
struct device_node *dp, *child;
struct property *prop;
enum op_inode_type ent_type;
union op_inode_data ent_data;
const char *name;
struct inode *inode;
unsigned int ino;
int len;
BUG_ON(oi->type != op_inode_node);
dp = oi->u.node;
name = dentry->d_name.name;
len = dentry->d_name.len;
mutex_lock(&op_mutex);
child = dp->child;
while (child) {
int n = strlen(child->path_component_name);
if (len == n &&
!strncmp(child->path_component_name, name, len)) {
ent_type = op_inode_node;
ent_data.node = child;
ino = child->unique_id;
goto found;
}
child = child->sibling;
}
prop = dp->properties;
while (prop) {
int n = strlen(prop->name);
if (len == n && !strncmp(prop->name, name, len)) {
ent_type = op_inode_prop;
ent_data.prop = prop;
ino = prop->unique_id;
goto found;
}
prop = prop->next;
}
mutex_unlock(&op_mutex);
return ERR_PTR(-ENOENT);
found:
inode = openprom_iget(dir->i_sb, ino);
mutex_unlock(&op_mutex);
if (IS_ERR(inode))
return ERR_CAST(inode);
ent_oi = OP_I(inode);
ent_oi->type = ent_type;
ent_oi->u = ent_data;
switch (ent_type) {
case op_inode_node:
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
inode->i_op = &openprom_inode_operations;
inode->i_fop = &openprom_operations;
set_nlink(inode, 2);
break;
case op_inode_prop:
if (!strcmp(dp->name, "options") && (len == 17) &&
!strncmp (name, "security-password", 17))
inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
else
inode->i_mode = S_IFREG | S_IRUGO;
inode->i_fop = &openpromfs_prop_ops;
set_nlink(inode, 1);
inode->i_size = ent_oi->u.prop->length;
break;
}
d_add(dentry, inode);
return NULL;
}
static int openpromfs_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
struct op_inode_info *oi = OP_I(inode);
struct device_node *dp = oi->u.node;
struct device_node *child;
struct property *prop;
int i;
mutex_lock(&op_mutex);
if (ctx->pos == 0) {
if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
goto out;
ctx->pos = 1;
}
if (ctx->pos == 1) {
if (!dir_emit(ctx, "..", 2,
(dp->parent == NULL ?
OPENPROM_ROOT_INO :
dp->parent->unique_id), DT_DIR))
goto out;
ctx->pos = 2;
}
i = ctx->pos - 2;
/* First, the children nodes as directories. */
child = dp->child;
while (i && child) {
child = child->sibling;
i--;
}
while (child) {
if (!dir_emit(ctx,
child->path_component_name,
strlen(child->path_component_name),
child->unique_id, DT_DIR))
goto out;
ctx->pos++;
child = child->sibling;
}
/* Next, the properties as files. */
prop = dp->properties;
while (i && prop) {
prop = prop->next;
i--;
}
while (prop) {
if (!dir_emit(ctx, prop->name, strlen(prop->name),
prop->unique_id, DT_REG))
goto out;
ctx->pos++;
prop = prop->next;
}
out:
mutex_unlock(&op_mutex);
return 0;
}
static struct kmem_cache *op_inode_cachep;
static struct inode *openprom_alloc_inode(struct super_block *sb)
{
struct op_inode_info *oi;
oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
if (!oi)
return NULL;
return &oi->vfs_inode;
}
static void openprom_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(op_inode_cachep, OP_I(inode));
}
static void openprom_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, openprom_i_callback);
}
static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
{
struct inode *inode;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (inode->i_state & I_NEW) {
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
if (inode->i_ino == OPENPROM_ROOT_INO) {
inode->i_op = &openprom_inode_operations;
inode->i_fop = &openprom_operations;
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
}
unlock_new_inode(inode);
}
return inode;
}
static int openprom_remount(struct super_block *sb, int *flags, char *data)
{
sync_filesystem(sb);
*flags |= MS_NOATIME;
return 0;
}
static const struct super_operations openprom_sops = {
.alloc_inode = openprom_alloc_inode,
.destroy_inode = openprom_destroy_inode,
.statfs = simple_statfs,
.remount_fs = openprom_remount,
};
static int openprom_fill_super(struct super_block *s, void *data, int silent)
{
struct inode *root_inode;
struct op_inode_info *oi;
int ret;
s->s_flags |= MS_NOATIME;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = OPENPROM_SUPER_MAGIC;
s->s_op = &openprom_sops;
s->s_time_gran = 1;
root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
if (IS_ERR(root_inode)) {
ret = PTR_ERR(root_inode);
goto out_no_root;
}
oi = OP_I(root_inode);
oi->type = op_inode_node;
oi->u.node = of_find_node_by_path("/");
s->s_root = d_make_root(root_inode);
if (!s->s_root)
goto out_no_root_dentry;
return 0;
out_no_root_dentry:
ret = -ENOMEM;
out_no_root:
printk("openprom_fill_super: get root inode failed\n");
return ret;
}
static struct dentry *openprom_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_single(fs_type, flags, data, openprom_fill_super);
}
static struct file_system_type openprom_fs_type = {
.owner = THIS_MODULE,
.name = "openpromfs",
.mount = openprom_mount,
.kill_sb = kill_anon_super,
};
MODULE_ALIAS_FS("openpromfs");
static void op_inode_init_once(void *data)
{
struct op_inode_info *oi = (struct op_inode_info *) data;
inode_init_once(&oi->vfs_inode);
}
static int __init init_openprom_fs(void)
{
int err;
op_inode_cachep = kmem_cache_create("op_inode_cache",
sizeof(struct op_inode_info),
0,
(SLAB_RECLAIM_ACCOUNT |
SLAB_MEM_SPREAD | SLAB_ACCOUNT),
op_inode_init_once);
if (!op_inode_cachep)
return -ENOMEM;
err = register_filesystem(&openprom_fs_type);
if (err)
kmem_cache_destroy(op_inode_cachep);
return err;
}
static void __exit exit_openprom_fs(void)
{
unregister_filesystem(&openprom_fs_type);
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(op_inode_cachep);
}
module_init(init_openprom_fs)
module_exit(exit_openprom_fs)
MODULE_LICENSE("GPL");