mtdchar: kill persistently held vfsmount
... and mtdchar_notifier along with it; just have ->drop_inode() that
will unconditionally get evict them instead of dances on mtd device
removal and use simple_pin_fs() instead of kern_mount()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index c57ae92..28c585f 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -39,7 +39,6 @@
#include <asm/uaccess.h>
static DEFINE_MUTEX(mtd_mutex);
-static struct vfsmount *mtd_inode_mnt __read_mostly;
/*
* Data structure to hold the pointer to the mtd device as well
@@ -75,7 +74,9 @@
return -EINVAL;
}
-
+static int count;
+static struct vfsmount *mnt;
+static struct file_system_type mtd_inodefs_type;
static int mtdchar_open(struct inode *inode, struct file *file)
{
@@ -92,6 +93,10 @@
if ((file->f_mode & FMODE_WRITE) && (minor & 1))
return -EACCES;
+ ret = simple_pin_fs(&mtd_inodefs_type, &mnt, &count);
+ if (ret)
+ return ret;
+
mutex_lock(&mtd_mutex);
mtd = get_mtd_device(NULL, devnum);
@@ -106,7 +111,7 @@
goto out;
}
- mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum);
+ mtd_ino = iget_locked(mnt->mnt_sb, devnum);
if (!mtd_ino) {
put_mtd_device(mtd);
ret = -ENOMEM;
@@ -141,6 +146,7 @@
out:
mutex_unlock(&mtd_mutex);
+ simple_release_fs(&mnt, &count);
return ret;
} /* mtdchar_open */
@@ -162,6 +168,7 @@
put_mtd_device(mtd);
file->private_data = NULL;
kfree(mfi);
+ simple_release_fs(&mnt, &count);
return 0;
} /* mtdchar_close */
@@ -1175,10 +1182,15 @@
#endif
};
+static const struct super_operations mtd_ops = {
+ .drop_inode = generic_delete_inode,
+ .statfs = simple_statfs,
+};
+
static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
- return mount_pseudo(fs_type, "mtd_inode:", NULL, NULL, MTD_INODE_FS_MAGIC);
+ return mount_pseudo(fs_type, "mtd_inode:", &mtd_ops, NULL, MTD_INODE_FS_MAGIC);
}
static struct file_system_type mtd_inodefs_type = {
@@ -1187,26 +1199,6 @@
.kill_sb = kill_anon_super,
};
-static void mtdchar_notify_add(struct mtd_info *mtd)
-{
-}
-
-static void mtdchar_notify_remove(struct mtd_info *mtd)
-{
- struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
-
- if (mtd_ino) {
- /* Destroy the inode if it exists */
- clear_nlink(mtd_ino);
- iput(mtd_ino);
- }
-}
-
-static struct mtd_notifier mtdchar_notifier = {
- .add = mtdchar_notify_add,
- .remove = mtdchar_notify_remove,
-};
-
static int __init init_mtdchar(void)
{
int ret;
@@ -1224,19 +1216,8 @@
pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
goto err_unregister_chdev;
}
-
- mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
- if (IS_ERR(mtd_inode_mnt)) {
- ret = PTR_ERR(mtd_inode_mnt);
- pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
- goto err_unregister_filesystem;
- }
- register_mtd_user(&mtdchar_notifier);
-
return ret;
-err_unregister_filesystem:
- unregister_filesystem(&mtd_inodefs_type);
err_unregister_chdev:
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
return ret;
@@ -1244,8 +1225,6 @@
static void __exit cleanup_mtdchar(void)
{
- unregister_mtd_user(&mtdchar_notifier);
- kern_unmount(mtd_inode_mnt);
unregister_filesystem(&mtd_inodefs_type);
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
}