[PATCH v5 07/28] netfs, mm: Move PG_fscache helper funcs to linux/netfs.h

[David Howells <dhowells@redhat.com>]

Move the PG_fscache related helper funcs (such as SetPageFsCache()) to
linux/netfs.h rather than linux/fscache.h as the intention is to move to a
model where they're used by the network filesystem and the helper library,
but not by fscache/cachefiles itself.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-mm@kvack.org
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/161340392347.1303470.18065131603507621762.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539534516.286939.6265142985563005000.stgit@warthog.procyon.org.uk/ # v4
---

 include/linux/fscache.h |   11 +----------
 include/linux/netfs.h   |   29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 10 deletions(-)
 create mode 100644 include/linux/netfs.h

diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index a1c928fe98e7..1f8dc72369ee 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -19,6 +19,7 @@
 #include <linux/pagemap.h>
 #include <linux/pagevec.h>
 #include <linux/list_bl.h>
+#include <linux/netfs.h>
 
 #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
 #define fscache_available() (1)
@@ -29,16 +30,6 @@
 #endif
 
 
-/*
- * overload PG_private_2 to give us PG_fscache - this is used to indicate that
- * a page is currently backed by a local disk cache
- */
-#define PageFsCache(page)		PagePrivate2((page))
-#define SetPageFsCache(page)		SetPagePrivate2((page))
-#define ClearPageFsCache(page)		ClearPagePrivate2((page))
-#define TestSetPageFsCache(page)	TestSetPagePrivate2((page))
-#define TestClearPageFsCache(page)	TestClearPagePrivate2((page))
-
 /* pattern used to fill dead space in an index entry */
 #define FSCACHE_INDEX_DEADFILL_PATTERN 0x79
 
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
new file mode 100644
index 000000000000..cc1102040488
--- /dev/null
+++ b/include/linux/netfs.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Network filesystem support services.
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * See:
+ *
+ *	Documentation/filesystems/netfs_library.rst
+ *
+ * for a description of the network filesystem interface declared here.
+ */
+
+#ifndef _LINUX_NETFS_H
+#define _LINUX_NETFS_H
+
+#include <linux/pagemap.h>
+
+/*
+ * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
+ * a page is currently backed by a local disk cache
+ */
+#define PageFsCache(page)		PagePrivate2((page))
+#define SetPageFsCache(page)		SetPagePrivate2((page))
+#define ClearPageFsCache(page)		ClearPagePrivate2((page))
+#define TestSetPageFsCache(page)	TestSetPagePrivate2((page))
+#define TestClearPageFsCache(page)	TestClearPagePrivate2((page))
+
+#endif /* _LINUX_NETFS_H */