From 23ca067b3295d935835b71f743235f9e5ab31cc5 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 1 Sep 2021 10:44:03 +0200
Subject: [PATCH] mm: Fully initialize invalidate_lock, amend lock class later
Git-commit: 23ca067b3295d935835b71f743235f9e5ab31cc5
Patch-mainline: v5.15-rc3
References: bsc#1197921

The function __init_rwsem() is not part of the official API, it just a helper
function used by init_rwsem().
Changing the lock's class and name should be done by using
lockdep_set_class_and_name() after the has been fully initialized. The overhead
of the additional class struct and setting it twice is negligible and it works
across all locks.

Fully initialize the lock with init_rwsem() and then set the custom class and
name for the lock.

Fixes: 730633f0b7f95 ("mm: Protect operations adding pages to page cache with invalidate_lock")
Link: https://lore.kernel.org/r/20210901084403.g4fezi23cixemlhh@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/inode.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 37710ca863b5..ed0cab8a32db 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -190,8 +190,10 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
 	mapping->private_data = NULL;
 	mapping->writeback_index = 0;
-	__init_rwsem(&mapping->invalidate_lock, "mapping.invalidate_lock",
-		     &sb->s_type->invalidate_lock_key);
+	init_rwsem(&mapping->invalidate_lock);
+	lockdep_set_class_and_name(&mapping->invalidate_lock,
+				   &sb->s_type->invalidate_lock_key,
+				   "mapping.invalidate_lock");
 	inode->i_private = NULL;
 	inode->i_mapping = mapping;
 	INIT_HLIST_HEAD(&inode->i_dentry);	/* buggered by rcu freeing */
-- 
2.34.1