switch inotify_user to anon_inode

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 6 insertions, 54 deletions

diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index a94e8bd8eb1f..472cdf29ef82 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -29,14 +29,12 @@
 #include <linux/init.h> /* module_init */
 #include <linux/inotify.h>
 #include <linux/kernel.h> /* roundup() */
-#include <linux/magic.h> /* superblock magic number */
-#include <linux/mount.h> /* mntget */
 #include <linux/namei.h> /* LOOKUP_FOLLOW */
-#include <linux/path.h> /* struct path */
 #include <linux/sched.h> /* struct user */
 #include <linux/slab.h> /* struct kmem_cache */
 #include <linux/syscalls.h>
 #include <linux/types.h>
+#include <linux/anon_inodes.h>
 #include <linux/uaccess.h>
 #include <linux/poll.h>
 #include <linux/wait.h>
@@ -45,8 +43,6 @@
 
 #include <asm/ioctls.h>
 
-static struct vfsmount *inotify_mnt __read_mostly;
-
 /* these are configurable via /proc/sys/fs/inotify/ */
 static int inotify_max_user_instances __read_mostly;
 static int inotify_max_queued_events __read_mostly;
@@ -645,9 +641,7 @@ SYSCALL_DEFINE1(inotify_init1, int, flags)
 {
         struct fsnotify_group *group;
         struct user_struct *user;
-        struct file *filp;
-        struct path path;
-        int fd, ret;
+        int ret;
 
         /* Check the IN_* constants for consistency.  */
         BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC);
@@ -656,10 +650,6 @@ SYSCALL_DEFINE1(inotify_init1, int, flags)
         if (flags & ~(IN_CLOEXEC | IN_NONBLOCK))
                 return -EINVAL;
 
-        fd = get_unused_fd_flags(flags & O_CLOEXEC);
-        if (fd < 0)
-                return fd;
-
         user = get_current_user();
         if (unlikely(atomic_read(&user->inotify_devs) >=
                         inotify_max_user_instances)) {
@@ -676,27 +666,14 @@ SYSCALL_DEFINE1(inotify_init1, int, flags)
 
         atomic_inc(&user->inotify_devs);
 
-        path.mnt = inotify_mnt;
-        path.dentry = inotify_mnt->mnt_root;
-        path_get(&path);
-        filp = alloc_file(&path, FMODE_READ, &inotify_fops);
-        if (!filp)
-                goto Enfile;
+        ret = anon_inode_getfd("inotify", &inotify_fops, group,
+                                  O_RDONLY | flags);
+        if (ret >= 0)
+                return ret;
 
-        filp->f_flags = O_RDONLY | (flags & O_NONBLOCK);
-        filp->private_data = group;
-
-        fd_install(fd, filp);
-
-        return fd;
-
-Enfile:
-        ret = -ENFILE;
-        path_put(&path);
         atomic_dec(&user->inotify_devs);
 out_free_uid:
         free_uid(user);
-        put_unused_fd(fd);
         return ret;
 }
 
@@ -783,20 +760,6 @@ out:
         return ret;
 }
 
-static int
-inotify_get_sb(struct file_system_type *fs_type, int flags,
-               const char *dev_name, void *data, struct vfsmount *mnt)
-{
-        return get_sb_pseudo(fs_type, "inotify", NULL,
-                        INOTIFYFS_SUPER_MAGIC, mnt);
-}
-
-static struct file_system_type inotify_fs_type = {
-    .name       = "inotifyfs",
-    .get_sb     = inotify_get_sb,
-    .kill_sb    = kill_anon_super,
-};
-
 /*
  * inotify_user_setup - Our initialization function.  Note that we cannnot return
  * error because we have compiled-in VFS hooks.  So an (unlikely) failure here
@@ -804,16 +767,6 @@ static struct file_system_type inotify_fs_type = {
  */
 static int __init inotify_user_setup(void)
 {
-        int ret;
-
-        ret = register_filesystem(&inotify_fs_type);
-        if (unlikely(ret))
-                panic("inotify: register_filesystem returned %d!\n", ret);
-
-        inotify_mnt = kern_mount(&inotify_fs_type);
-        if (IS_ERR(inotify_mnt))
-                panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt));
-
         inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC);
         event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);
 
diff --git a/include/linux/magic.h b/include/linux/magic.h
index 76285e01b39e..eb9800f05782 100644
--- a/include/linux/magic.h
+++ b/include/linux/magic.h
@@ -52,7 +52,6 @@
 #define CGROUP_SUPER_MAGIC      0x27e0eb
 
 #define FUTEXFS_SUPER_MAGIC     0xBAD1DEA
-#define INOTIFYFS_SUPER_MAGIC   0x2BAD1DEA
 
 #define STACK_END_MAGIC         0x57AC6E9D