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/* 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))
/**
* set_page_fscache - Set PG_fscache on a page and take a ref
* @page: The page.
*
* Set the PG_fscache (PG_private_2) flag on a page and take the reference
* needed for the VM to handle its lifetime correctly. This sets the flag and
* takes the reference unconditionally, so care must be taken not to set the
* flag again if it's already set.
*/
static inline void set_page_fscache(struct page *page)
{
set_page_private_2(page);
}
/**
* end_page_fscache - Clear PG_fscache and release any waiters
* @page: The page
*
* Clear the PG_fscache (PG_private_2) bit on a page and wake up any sleepers
* waiting for this. The page ref held for PG_private_2 being set is released.
*
* This is, for example, used when a netfs page is being written to a local
* disk cache, thereby allowing writes to the cache for the same page to be
* serialised.
*/
static inline void end_page_fscache(struct page *page)
{
end_page_private_2(page);
}
/**
* wait_on_page_fscache - Wait for PG_fscache to be cleared on a page
* @page: The page to wait on
*
* Wait for PG_fscache (aka PG_private_2) to be cleared on a page.
*/
static inline void wait_on_page_fscache(struct page *page)
{
wait_on_page_private_2(page);
}
/**
* wait_on_page_fscache_killable - Wait for PG_fscache to be cleared on a page
* @page: The page to wait on
*
* Wait for PG_fscache (aka PG_private_2) to be cleared on a page or until a
* fatal signal is received by the calling task.
*
* Return:
* - 0 if successful.
* - -EINTR if a fatal signal was encountered.
*/
static inline int wait_on_page_fscache_killable(struct page *page)
{
return wait_on_page_private_2_killable(page);
}
#endif /* _LINUX_NETFS_H */
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