cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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aops.h (3232B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/**
      3 * aops.h - Defines for NTFS kernel address space operations and page cache
      4 *	    handling.  Part of the Linux-NTFS project.
      5 *
      6 * Copyright (c) 2001-2004 Anton Altaparmakov
      7 * Copyright (c) 2002 Richard Russon
      8 */
      9
     10#ifndef _LINUX_NTFS_AOPS_H
     11#define _LINUX_NTFS_AOPS_H
     12
     13#include <linux/mm.h>
     14#include <linux/highmem.h>
     15#include <linux/pagemap.h>
     16#include <linux/fs.h>
     17
     18#include "inode.h"
     19
     20/**
     21 * ntfs_unmap_page - release a page that was mapped using ntfs_map_page()
     22 * @page:	the page to release
     23 *
     24 * Unpin, unmap and release a page that was obtained from ntfs_map_page().
     25 */
     26static inline void ntfs_unmap_page(struct page *page)
     27{
     28	kunmap(page);
     29	put_page(page);
     30}
     31
     32/**
     33 * ntfs_map_page - map a page into accessible memory, reading it if necessary
     34 * @mapping:	address space for which to obtain the page
     35 * @index:	index into the page cache for @mapping of the page to map
     36 *
     37 * Read a page from the page cache of the address space @mapping at position
     38 * @index, where @index is in units of PAGE_SIZE, and not in bytes.
     39 *
     40 * If the page is not in memory it is loaded from disk first using the
     41 * read_folio method defined in the address space operations of @mapping
     42 * and the page is added to the page cache of @mapping in the process.
     43 *
     44 * If the page belongs to an mst protected attribute and it is marked as such
     45 * in its ntfs inode (NInoMstProtected()) the mst fixups are applied but no
     46 * error checking is performed.  This means the caller has to verify whether
     47 * the ntfs record(s) contained in the page are valid or not using one of the
     48 * ntfs_is_XXXX_record{,p}() macros, where XXXX is the record type you are
     49 * expecting to see.  (For details of the macros, see fs/ntfs/layout.h.)
     50 *
     51 * If the page is in high memory it is mapped into memory directly addressible
     52 * by the kernel.
     53 *
     54 * Finally the page count is incremented, thus pinning the page into place.
     55 *
     56 * The above means that page_address(page) can be used on all pages obtained
     57 * with ntfs_map_page() to get the kernel virtual address of the page.
     58 *
     59 * When finished with the page, the caller has to call ntfs_unmap_page() to
     60 * unpin, unmap and release the page.
     61 *
     62 * Note this does not grant exclusive access. If such is desired, the caller
     63 * must provide it independently of the ntfs_{un}map_page() calls by using
     64 * a {rw_}semaphore or other means of serialization. A spin lock cannot be
     65 * used as ntfs_map_page() can block.
     66 *
     67 * The unlocked and uptodate page is returned on success or an encoded error
     68 * on failure. Caller has to test for error using the IS_ERR() macro on the
     69 * return value. If that evaluates to 'true', the negative error code can be
     70 * obtained using PTR_ERR() on the return value of ntfs_map_page().
     71 */
     72static inline struct page *ntfs_map_page(struct address_space *mapping,
     73		unsigned long index)
     74{
     75	struct page *page = read_mapping_page(mapping, index, NULL);
     76
     77	if (!IS_ERR(page)) {
     78		kmap(page);
     79		if (!PageError(page))
     80			return page;
     81		ntfs_unmap_page(page);
     82		return ERR_PTR(-EIO);
     83	}
     84	return page;
     85}
     86
     87#ifdef NTFS_RW
     88
     89extern void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs);
     90
     91#endif /* NTFS_RW */
     92
     93#endif /* _LINUX_NTFS_AOPS_H */