Commit ff0c7d15 authored by Nick Piggin's avatar Nick Piggin

fs: avoid inode RCU freeing for pseudo fs

Pseudo filesystems that don't put inode on RCU list or reachable by
rcu-walk dentries do not need to RCU free their inodes.
Signed-off-by: default avatarNick Piggin <>
parent fa0d7e3d
......@@ -257,6 +257,12 @@ static struct inode *alloc_inode(struct super_block *sb)
return inode;
void free_inode_nonrcu(struct inode *inode)
kmem_cache_free(inode_cachep, inode);
void __destroy_inode(struct inode *inode)
......@@ -1253,6 +1253,10 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
return ret;
static const struct super_operations pipefs_ops = {
.destroy_inode = free_inode_nonrcu,
* pipefs should _never_ be mounted by userland - too much of security hassle,
* no real gain from having the whole whorehouse mounted. So we don't need
......@@ -1262,7 +1266,7 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
static struct dentry *pipefs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
return mount_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC);
return mount_pseudo(fs_type, "pipe:", &pipefs_ops, PIPEFS_MAGIC);
static struct file_system_type pipe_fs_type = {
......@@ -2233,6 +2233,7 @@ extern void iget_failed(struct inode *);
extern void end_writeback(struct inode *);
extern void __destroy_inode(struct inode *);
extern struct inode *new_inode(struct super_block *);
extern void free_inode_nonrcu(struct inode *inode);
extern int should_remove_suid(struct dentry *);
extern int file_remove_suid(struct file *);
......@@ -120,6 +120,7 @@ enum sock_shutdown_cmd {
struct socket_wq {
wait_queue_head_t wait;
struct fasync_struct *fasync_list;
struct rcu_head rcu;
} ____cacheline_aligned_in_smp;
......@@ -262,20 +262,21 @@ static struct inode *sock_alloc_inode(struct super_block *sb)
static void sock_free_rcu(struct rcu_head *head)
static void wq_free_rcu(struct rcu_head *head)
struct inode *inode = container_of(head, struct inode, i_rcu);
struct socket_alloc *ei = container_of(inode, struct socket_alloc,
struct socket_wq *wq = container_of(head, struct socket_wq, rcu);
kmem_cache_free(sock_inode_cachep, ei);
static void sock_destroy_inode(struct inode *inode)
call_rcu(&inode->i_rcu, sock_free_rcu);
struct socket_alloc *ei;
ei = container_of(inode, struct socket_alloc, vfs_inode);
call_rcu(&ei->socket.wq->rcu, wq_free_rcu);
kmem_cache_free(sock_inode_cachep, ei);
static void init_once(void *foo)
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