release/5.2.46/cgroup-blkcg-Prepare-some-symbols-for-module-and-CON.patch

From fbedd26b476df68bb538a1567ebfc1097f4a38b6 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Thu, 27 Jun 2019 13:39:48 -0700
Subject: [PATCH] cgroup, blkcg: Prepare some symbols for module and
 !CONFIG_CGROUP usages

commit 9b0eb69b75bccada2d341d7e7ca342f0cb1c9a6a upstream.

btrfs is going to use css_put() and wbc helpers to improve cgroup
writeback support.  Add dummy css_get() definition and export wbc
helpers to prepare for module and !CONFIG_CGROUP builds.

[only backport the export of __inode_attach_wb for stable kernels - gregkh]

Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[PG: borrow Greg's stable fix from v4.19 for v5.2.x here.]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 5f8cca58b9c0..76ff35d3a430 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -270,6 +270,7 @@ void __inode_attach_wb(struct inode *inode, struct page *page)
 	if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
 		wb_put(wb);
 }
+EXPORT_SYMBOL_GPL(__inode_attach_wb);
 
 /**
  * locked_inode_to_wb_and_lock_list - determine a locked inode's wb and lock it
-- 
2.7.4