From eb7ae5e06bb6e6ac6bb86872d27c43ebab92f6b2 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 4 May 2020 14:47:54 +0200
Subject: [PATCH] bdi: move bdi_dev_name out of line
Git-commit: eb7ae5e06bb6e6ac6bb86872d27c43ebab92f6b2
Patch-mainline: v5.7-rc5
References: bsc#1171844

bdi_dev_name is not a fast path function, move it out of line.  This
prepares for using it from modular callers without having to export
an implementation detail like bdi_unknown_name.

kABI note: bdi_dev_name() could never be used in a module because
bdi_unknown_name used there is not exported. So this move is irrelevant for
kABI.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Jan Kara <jack@suse.cz>

---
 include/linux/backing-dev.h |  9 +--------
 mm/backing-dev.c            | 10 +++++++++-
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index f88197c1ffc2..c9ad5c3b7b4b 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -505,13 +505,6 @@ static inline int bdi_rw_congested(struct backing_dev_info *bdi)
 				  (1 << WB_async_congested));
 }
 
-extern const char *bdi_unknown_name;
-
-static inline const char *bdi_dev_name(struct backing_dev_info *bdi)
-{
-	if (!bdi || !bdi->dev)
-		return bdi_unknown_name;
-	return dev_name(bdi->dev);
-}
+const char *bdi_dev_name(struct backing_dev_info *bdi);
 
 #endif	/* _LINUX_BACKING_DEV_H */
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index c81b4f3a7268..c2c44c89ee5d 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -21,7 +21,7 @@ struct backing_dev_info noop_backing_dev_info = {
 EXPORT_SYMBOL_GPL(noop_backing_dev_info);
 
 static struct class *bdi_class;
-const char *bdi_unknown_name = "(unknown)";
+static const char *bdi_unknown_name = "(unknown)";
 
 /*
  * bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU
@@ -1043,6 +1043,14 @@ void bdi_put(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL(bdi_put);
 
+const char *bdi_dev_name(struct backing_dev_info *bdi)
+{
+	if (!bdi || !bdi->dev)
+		return bdi_unknown_name;
+	return dev_name(bdi->dev);
+}
+EXPORT_SYMBOL_GPL(bdi_dev_name);
+
 static wait_queue_head_t congestion_wqh[2] = {
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
-- 
2.16.4