proc: fix proc_kill_inodes to kill dentries on all proc superblocks

It appears we overlooked support for removing generic proc files
when we added support for multiple proc super blocks.  Handle
that now.

[akpm@linux-foundation.org: coding-style cleanups]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/generic.c

@@ -561,16 +561,19 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
 static void proc_kill_inodes(struct proc_dir_entry *de)
 {
 	struct list_head *p;
-	struct super_block *sb = proc_mnt->mnt_sb;
+	struct super_block *sb;
 
 	/*
 	 * Actually it's a partial revoke().
 	 */
+	spin_lock(&sb_lock);
+	list_for_each_entry(sb, &proc_fs_type.fs_supers, s_instances) {
 		file_list_lock();
 		list_for_each(p, &sb->s_files) {
-		struct file * filp = list_entry(p, struct file, f_u.fu_list);
-		struct dentry * dentry = filp->f_path.dentry;
-		struct inode * inode;
+			struct file *filp = list_entry(p, struct file,
+							f_u.fu_list);
+			struct dentry *dentry = filp->f_path.dentry;
+			struct inode *inode;
 			const struct file_operations *fops;
 
 			if (dentry->d_op != &proc_dentry_operations)
@@ -583,6 +586,8 @@ static void proc_kill_inodes(struct proc_dir_entry *de)
 			fops_put(fops);
 		}
 		file_list_unlock();
+	}
+	spin_unlock(&sb_lock);
 }
 
 static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,

fs/proc/internal.h

@@ -78,3 +78,5 @@ static inline int proc_fd(struct inode *inode)
 {
 	return PROC_I(inode)->fd;
 }
+
+extern struct file_system_type proc_fs_type;

fs/proc/root.c

@@ -98,7 +98,7 @@ static void proc_kill_sb(struct super_block *sb)
 	put_pid_ns(ns);
 }
 
-static struct file_system_type proc_fs_type = {
+struct file_system_type proc_fs_type = {
 	.name		= "proc",
 	.get_sb		= proc_get_sb,
 	.kill_sb	= proc_kill_sb,