9 files changed, 249 insertions, 217 deletions

diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index 99349efbbc2b..981b05601931 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -21,6 +21,7 @@ proc-y	+= uptime.o
 proc-y  += version.o
 proc-y  += softirqs.o
 proc-y  += namespaces.o
+proc-y  += self.o
 proc-$(CONFIG_PROC_SYSCTL)      += proc_sysctl.o
 proc-$(CONFIG_NET)              += proc_net.o
 proc-$(CONFIG_PROC_KCORE)       += kcore.o
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 060a56a91278..6a91e6ffbcbd 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -162,7 +162,7 @@ static inline const char *get_task_state(struct task_struct *tsk)
 static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
                                 struct pid *pid, struct task_struct *p)
 {
-        struct user_namespace *user_ns = current_user_ns();
+        struct user_namespace *user_ns = seq_user_ns(m);
         struct group_info *group_info;
         int g;
         struct fdtable *fdt = NULL;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index aa63d25157b8..5a5a0be40e40 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2345,146 +2345,6 @@ static const struct file_operations proc_coredump_filter_operations = {
 };
 #endif
 
-/*
- * /proc/self:
- */
-static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
-                              int buflen)
-{
-        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
-        pid_t tgid = task_tgid_nr_ns(current, ns);
-        char tmp[PROC_NUMBUF];
-        if (!tgid)
-                return -ENOENT;
-        sprintf(tmp, "%d", tgid);
-        return vfs_readlink(dentry,buffer,buflen,tmp);
-}
-
-static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
-        pid_t tgid = task_tgid_nr_ns(current, ns);
-        char *name = ERR_PTR(-ENOENT);
-        if (tgid) {
-                /* 11 for max length of signed int in decimal + NULL term */
-                name = kmalloc(12, GFP_KERNEL);
-                if (!name)
-                        name = ERR_PTR(-ENOMEM);
-                else
-                        sprintf(name, "%d", tgid);
-        }
-        nd_set_link(nd, name);
-        return NULL;
-}
-
-static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
-                                void *cookie)
-{
-        char *s = nd_get_link(nd);
-        if (!IS_ERR(s))
-                kfree(s);
-}
-
-static const struct inode_operations proc_self_inode_operations = {
-        .readlink       = proc_self_readlink,
-        .follow_link    = proc_self_follow_link,
-        .put_link       = proc_self_put_link,
-};
-
-/*
- * proc base
- *
- * These are the directory entries in the root directory of /proc
- * that properly belong to the /proc filesystem, as they describe
- * describe something that is process related.
- */
-static const struct pid_entry proc_base_stuff[] = {
-        NOD("self", S_IFLNK|S_IRWXUGO,
-                &proc_self_inode_operations, NULL, {}),
-};
-
-static struct dentry *proc_base_instantiate(struct inode *dir,
-        struct dentry *dentry, struct task_struct *task, const void *ptr)
-{
-        const struct pid_entry *p = ptr;
-        struct inode *inode;
-        struct proc_inode *ei;
-        struct dentry *error;
-
-        /* Allocate the inode */
-        error = ERR_PTR(-ENOMEM);
-        inode = new_inode(dir->i_sb);
-        if (!inode)
-                goto out;
-
-        /* Initialize the inode */
-        ei = PROC_I(inode);
-        inode->i_ino = get_next_ino();
-        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-
-        /*
-         * grab the reference to the task.
-         */
-        ei->pid = get_task_pid(task, PIDTYPE_PID);
-        if (!ei->pid)
-                goto out_iput;
-
-        inode->i_mode = p->mode;
-        if (S_ISDIR(inode->i_mode))
-                set_nlink(inode, 2);
-        if (S_ISLNK(inode->i_mode))
-                inode->i_size = 64;
-        if (p->iop)
-                inode->i_op = p->iop;
-        if (p->fop)
-                inode->i_fop = p->fop;
-        ei->op = p->op;
-        d_add(dentry, inode);
-        error = NULL;
-out:
-        return error;
-out_iput:
-        iput(inode);
-        goto out;
-}
-
-static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
-{
-        struct dentry *error;
-        struct task_struct *task = get_proc_task(dir);
-        const struct pid_entry *p, *last;
-
-        error = ERR_PTR(-ENOENT);
-
-        if (!task)
-                goto out_no_task;
-
-        /* Lookup the directory entry */
-        last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1];
-        for (p = proc_base_stuff; p <= last; p++) {
-                if (p->len != dentry->d_name.len)
-                        continue;
-                if (!memcmp(dentry->d_name.name, p->name, p->len))
-                        break;
-        }
-        if (p > last)
-                goto out;
-
-        error = proc_base_instantiate(dir, dentry, task, p);
-
-out:
-        put_task_struct(task);
-out_no_task:
-        return error;
-}
-
-static int proc_base_fill_cache(struct file *filp, void *dirent,
-        filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
-{
-        return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
-                                proc_base_instantiate, task, p);
-}
-
 #ifdef CONFIG_TASK_IO_ACCOUNTING
 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
 {
@@ -2839,10 +2699,6 @@ void proc_flush_task(struct task_struct *task)
                 proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
                                         tgid->numbers[i].nr);
         }
-
-        upid = &pid->numbers[pid->level];
-        if (upid->nr == 1)
-                pid_ns_release_proc(upid->ns);
 }
 
 static struct dentry *proc_pid_instantiate(struct inode *dir,
@@ -2876,15 +2732,11 @@ out:
 
 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
 {
-        struct dentry *result;
+        struct dentry *result = NULL;
         struct task_struct *task;
         unsigned tgid;
         struct pid_namespace *ns;
 
-        result = proc_base_lookup(dir, dentry);
-        if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
-                goto out;
-
         tgid = name_to_int(dentry);
         if (tgid == ~0U)
                 goto out;
@@ -2947,7 +2799,7 @@ retry:
         return iter;
 }
 
-#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
+#define TGID_OFFSET (FIRST_PROCESS_ENTRY)
 
 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
         struct tgid_iter iter)
@@ -2967,25 +2819,12 @@ static int fake_filldir(void *buf, const char *name, int namelen,
 /* for the /proc/ directory itself, after non-process stuff has been done */
 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
-        unsigned int nr;
-        struct task_struct *reaper;
         struct tgid_iter iter;
         struct pid_namespace *ns;
         filldir_t __filldir;
 
         if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
-                goto out_no_task;
-        nr = filp->f_pos - FIRST_PROCESS_ENTRY;
-
-        reaper = get_proc_task(filp->f_path.dentry->d_inode);
-        if (!reaper)
-                goto out_no_task;
-
-        for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
-                const struct pid_entry *p = &proc_base_stuff[nr];
-                if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
-                        goto out;
-        }
+                goto out;
 
         ns = filp->f_dentry->d_sb->s_fs_info;
         iter.task = NULL;
@@ -3006,8 +2845,6 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
         }
         filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET;
 out:
-        put_task_struct(reaper);
-out_no_task:
         return 0;
 }
 
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 0d80cef4cfb9..7b3ae3cc0ef9 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -350,14 +350,14 @@ static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
  * Return an inode number between PROC_DYNAMIC_FIRST and
  * 0xffffffff, or zero on failure.
  */
-static unsigned int get_inode_number(void)
+int proc_alloc_inum(unsigned int *inum)
 {
         unsigned int i;
         int error;
 
 retry:
-        if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0)
-                return 0;
+        if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
+                return -ENOMEM;
 
         spin_lock(&proc_inum_lock);
         error = ida_get_new(&proc_inum_ida, &i);
@@ -365,18 +365,19 @@ retry:
         if (error == -EAGAIN)
                 goto retry;
         else if (error)
-                return 0;
+                return error;
 
         if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
                 spin_lock(&proc_inum_lock);
                 ida_remove(&proc_inum_ida, i);
                 spin_unlock(&proc_inum_lock);
-                return 0;
+                return -ENOSPC;
         }
-        return PROC_DYNAMIC_FIRST + i;
+        *inum = PROC_DYNAMIC_FIRST + i;
+        return 0;
 }
 
-static void release_inode_number(unsigned int inum)
+void proc_free_inum(unsigned int inum)
 {
         spin_lock(&proc_inum_lock);
         ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
@@ -554,13 +555,12 @@ static const struct inode_operations proc_dir_inode_operations = {
 
 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
 {
-        unsigned int i;
         struct proc_dir_entry *tmp;
+        int ret;
         
-        i = get_inode_number();
-        if (i == 0)
-                return -EAGAIN;
-        dp->low_ino = i;
+        ret = proc_alloc_inum(&dp->low_ino);
+        if (ret)
+                return ret;
 
         if (S_ISDIR(dp->mode)) {
                 if (dp->proc_iops == NULL) {
@@ -764,7 +764,7 @@ EXPORT_SYMBOL(proc_create_data);
 
 static void free_proc_entry(struct proc_dir_entry *de)
 {
-        release_inode_number(de->low_ino);
+        proc_free_inum(de->low_ino);
 
         if (S_ISLNK(de->mode))
                 kfree(de->data);
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 3b22bbdee9ec..439ae6886507 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -31,6 +31,7 @@ static void proc_evict_inode(struct inode *inode)
         struct proc_dir_entry *de;
         struct ctl_table_header *head;
         const struct proc_ns_operations *ns_ops;
+        void *ns;
 
         truncate_inode_pages(&inode->i_data, 0);
         clear_inode(inode);
@@ -49,8 +50,9 @@ static void proc_evict_inode(struct inode *inode)
         }
         /* Release any associated namespace */
         ns_ops = PROC_I(inode)->ns_ops;
-        if (ns_ops && ns_ops->put)
-                ns_ops->put(PROC_I(inode)->ns);
+        ns = PROC_I(inode)->ns;
+        if (ns_ops && ns)
+                ns_ops->put(ns);
 }
 
 static struct kmem_cache * proc_inode_cachep;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 43973b084abf..252544c05207 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -15,6 +15,7 @@ struct  ctl_table_header;
 struct  mempolicy;
 
 extern struct proc_dir_entry proc_root;
+extern void proc_self_init(void);
 #ifdef CONFIG_PROC_SYSCTL
 extern int proc_sys_init(void);
 extern void sysctl_head_put(struct ctl_table_header *head);
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index b178ed733c36..b7a47196c8c3 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -11,6 +11,7 @@
 #include <net/net_namespace.h>
 #include <linux/ipc_namespace.h>
 #include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
 #include "internal.h"
 
 
@@ -24,12 +25,168 @@ static const struct proc_ns_operations *ns_entries[] = {
 #ifdef CONFIG_IPC_NS
         &ipcns_operations,
 #endif
+#ifdef CONFIG_PID_NS
+        &pidns_operations,
+#endif
+#ifdef CONFIG_USER_NS
+        &userns_operations,
+#endif
+        &mntns_operations,
 };
 
 static const struct file_operations ns_file_operations = {
         .llseek         = no_llseek,
 };
 
+static const struct inode_operations ns_inode_operations = {
+        .setattr        = proc_setattr,
+};
+
+static int ns_delete_dentry(const struct dentry *dentry)
+{
+        /* Don't cache namespace inodes when not in use */
+        return 1;
+}
+
+static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+        struct inode *inode = dentry->d_inode;
+        const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
+
+        return dynamic_dname(dentry, buffer, buflen, "%s:[%lu]",
+                ns_ops->name, inode->i_ino);
+}
+
+const struct dentry_operations ns_dentry_operations =
+{
+        .d_delete       = ns_delete_dentry,
+        .d_dname        = ns_dname,
+};
+
+static struct dentry *proc_ns_get_dentry(struct super_block *sb,
+        struct task_struct *task, const struct proc_ns_operations *ns_ops)
+{
+        struct dentry *dentry, *result;
+        struct inode *inode;
+        struct proc_inode *ei;
+        struct qstr qname = { .name = "", };
+        void *ns;
+
+        ns = ns_ops->get(task);
+        if (!ns)
+                return ERR_PTR(-ENOENT);
+
+        dentry = d_alloc_pseudo(sb, &qname);
+        if (!dentry) {
+                ns_ops->put(ns);
+                return ERR_PTR(-ENOMEM);
+        }
+
+        inode = iget_locked(sb, ns_ops->inum(ns));
+        if (!inode) {
+                dput(dentry);
+                ns_ops->put(ns);
+                return ERR_PTR(-ENOMEM);
+        }
+
+        ei = PROC_I(inode);
+        if (inode->i_state & I_NEW) {
+                inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+                inode->i_op = &ns_inode_operations;
+                inode->i_mode = S_IFREG | S_IRUGO;
+                inode->i_fop = &ns_file_operations;
+                ei->ns_ops = ns_ops;
+                ei->ns = ns;
+                unlock_new_inode(inode);
+        } else {
+                ns_ops->put(ns);
+        }
+
+        d_set_d_op(dentry, &ns_dentry_operations);
+        result = d_instantiate_unique(dentry, inode);
+        if (result) {
+                dput(dentry);
+                dentry = result;
+        }
+
+        return dentry;
+}
+
+static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+        struct inode *inode = dentry->d_inode;
+        struct super_block *sb = inode->i_sb;
+        struct proc_inode *ei = PROC_I(inode);
+        struct task_struct *task;
+        struct dentry *ns_dentry;
+        void *error = ERR_PTR(-EACCES);
+
+        task = get_proc_task(inode);
+        if (!task)
+                goto out;
+
+        if (!ptrace_may_access(task, PTRACE_MODE_READ))
+                goto out_put_task;
+
+        ns_dentry = proc_ns_get_dentry(sb, task, ei->ns_ops);
+        if (IS_ERR(ns_dentry)) {
+                error = ERR_CAST(ns_dentry);
+                goto out_put_task;
+        }
+
+        dput(nd->path.dentry);
+        nd->path.dentry = ns_dentry;
+        error = NULL;
+
+out_put_task:
+        put_task_struct(task);
+out:
+        return error;
+}
+
+static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
+{
+        struct inode *inode = dentry->d_inode;
+        struct proc_inode *ei = PROC_I(inode);
+        const struct proc_ns_operations *ns_ops = ei->ns_ops;
+        struct task_struct *task;
+        void *ns;
+        char name[50];
+        int len = -EACCES;
+
+        task = get_proc_task(inode);
+        if (!task)
+                goto out;
+
+        if (!ptrace_may_access(task, PTRACE_MODE_READ))
+                goto out_put_task;
+
+        len = -ENOENT;
+        ns = ns_ops->get(task);
+        if (!ns)
+                goto out_put_task;
+
+        snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));
+        len = strlen(name);
+
+        if (len > buflen)
+                len = buflen;
+        if (copy_to_user(buffer, name, len))
+                len = -EFAULT;
+
+        ns_ops->put(ns);
+out_put_task:
+        put_task_struct(task);
+out:
+        return len;
+}
+
+static const struct inode_operations proc_ns_link_inode_operations = {
+        .readlink       = proc_ns_readlink,
+        .follow_link    = proc_ns_follow_link,
+        .setattr        = proc_setattr,
+};
+
 static struct dentry *proc_ns_instantiate(struct inode *dir,
         struct dentry *dentry, struct task_struct *task, const void *ptr)
 {
@@ -37,21 +194,15 @@ static struct dentry *proc_ns_instantiate(struct inode *dir,
         struct inode *inode;
         struct proc_inode *ei;
         struct dentry *error = ERR_PTR(-ENOENT);
-        void *ns;
 
         inode = proc_pid_make_inode(dir->i_sb, task);
         if (!inode)
                 goto out;
 
-        ns = ns_ops->get(task);
-        if (!ns)
-                goto out_iput;
-
         ei = PROC_I(inode);
-        inode->i_mode = S_IFREG|S_IRUSR;
-        inode->i_fop  = &ns_file_operations;
-        ei->ns_ops    = ns_ops;
-        ei->ns        = ns;
+        inode->i_mode = S_IFLNK|S_IRWXUGO;
+        inode->i_op = &proc_ns_link_inode_operations;
+        ei->ns_ops = ns_ops;
 
         d_set_d_op(dentry, &pid_dentry_operations);
         d_add(dentry, inode);
@@ -60,9 +211,6 @@ static struct dentry *proc_ns_instantiate(struct inode *dir,
                 error = NULL;
 out:
         return error;
-out_iput:
-        iput(inode);
-        goto out;
 }
 
 static int proc_ns_fill_cache(struct file *filp, void *dirent,
@@ -89,10 +237,6 @@ static int proc_ns_dir_readdir(struct file *filp, void *dirent,
         if (!task)
                 goto out_no_task;
 
-        ret = -EPERM;
-        if (!ptrace_may_access(task, PTRACE_MODE_READ))
-                goto out;
-
         ret = 0;
         i = filp->f_pos;
         switch (i) {
@@ -152,10 +296,6 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
         if (!task)
                 goto out_no_task;
 
-        error = ERR_PTR(-EPERM);
-        if (!ptrace_may_access(task, PTRACE_MODE_READ))
-                goto out;
-
         last = &ns_entries[ARRAY_SIZE(ns_entries)];
         for (entry = ns_entries; entry < last; entry++) {
                 if (strlen((*entry)->name) != len)
@@ -163,7 +303,6 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
                 if (!memcmp(dentry->d_name.name, (*entry)->name, len))
                         break;
         }
-        error = ERR_PTR(-ENOENT);
         if (entry == last)
                 goto out;
 
@@ -198,3 +337,7 @@ out_invalid:
         return ERR_PTR(-EINVAL);
 }
 
+bool proc_ns_inode(struct inode *inode)
+{
+        return inode->i_fop == &ns_file_operations;
+}
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 9889a92d2e01..c6e9fac26bac 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -100,14 +100,13 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
         int err;
         struct super_block *sb;
         struct pid_namespace *ns;
-        struct proc_inode *ei;
         char *options;
 
         if (flags & MS_KERNMOUNT) {
                 ns = (struct pid_namespace *)data;
                 options = NULL;
         } else {
-                ns = current->nsproxy->pid_ns;
+                ns = task_active_pid_ns(current);
                 options = data;
         }
 
@@ -130,13 +129,6 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
                 sb->s_flags |= MS_ACTIVE;
         }
 
-        ei = PROC_I(sb->s_root->d_inode);
-        if (!ei->pid) {
-                rcu_read_lock();
-                ei->pid = get_pid(find_pid_ns(1, ns));
-                rcu_read_unlock();
-        }
-
         return dget(sb->s_root);
 }
 
@@ -153,6 +145,7 @@ static struct file_system_type proc_fs_type = {
         .name           = "proc",
         .mount          = proc_mount,
         .kill_sb        = proc_kill_sb,
+        .fs_flags       = FS_USERNS_MOUNT,
 };
 
 void __init proc_root_init(void)
@@ -163,12 +156,8 @@ void __init proc_root_init(void)
         err = register_filesystem(&proc_fs_type);
         if (err)
                 return;
-        err = pid_ns_prepare_proc(&init_pid_ns);
-        if (err) {
-                unregister_filesystem(&proc_fs_type);
-                return;
-        }
 
+        proc_self_init();
         proc_symlink("mounts", NULL, "self/mounts");
 
         proc_net_init();
diff --git a/fs/proc/self.c b/fs/proc/self.c
new file mode 100644
index 000000000000..aa5cc3bff140
--- /dev/null
+++ b/fs/proc/self.c
@@ -0,0 +1,59 @@
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/namei.h>
+
+/*
+ * /proc/self:
+ */
+static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
+                              int buflen)
+{
+        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+        pid_t tgid = task_tgid_nr_ns(current, ns);
+        char tmp[PROC_NUMBUF];
+        if (!tgid)
+                return -ENOENT;
+        sprintf(tmp, "%d", tgid);
+        return vfs_readlink(dentry,buffer,buflen,tmp);
+}
+
+static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+        struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+        pid_t tgid = task_tgid_nr_ns(current, ns);
+        char *name = ERR_PTR(-ENOENT);
+        if (tgid) {
+                /* 11 for max length of signed int in decimal + NULL term */
+                name = kmalloc(12, GFP_KERNEL);
+                if (!name)
+                        name = ERR_PTR(-ENOMEM);
+                else
+                        sprintf(name, "%d", tgid);
+        }
+        nd_set_link(nd, name);
+        return NULL;
+}
+
+static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
+                                void *cookie)
+{
+        char *s = nd_get_link(nd);
+        if (!IS_ERR(s))
+                kfree(s);
+}
+
+static const struct inode_operations proc_self_inode_operations = {
+        .readlink       = proc_self_readlink,
+        .follow_link    = proc_self_follow_link,
+        .put_link       = proc_self_put_link,
+};
+
+void __init proc_self_init(void)
+{
+        struct proc_dir_entry *proc_self_symlink;
+        mode_t mode;
+
+        mode = S_IFLNK | S_IRWXUGO;
+        proc_self_symlink = proc_create("self", mode, NULL, NULL );
+        proc_self_symlink->proc_iops = &proc_self_inode_operations;
+}