cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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reservations.h (4776B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * reservations.h
      4 *
      5 * Allocation reservations function prototypes and structures.
      6 *
      7 * Copyright (C) 2010 Novell.  All rights reserved.
      8 */
      9
     10#ifndef	OCFS2_RESERVATIONS_H
     11#define	OCFS2_RESERVATIONS_H
     12
     13#include <linux/rbtree.h>
     14
     15#define OCFS2_DEFAULT_RESV_LEVEL	2
     16#define OCFS2_MAX_RESV_LEVEL	9
     17#define OCFS2_MIN_RESV_LEVEL	0
     18
     19struct ocfs2_alloc_reservation {
     20	struct rb_node	r_node;
     21
     22	unsigned int	r_start;	/* Beginning of current window */
     23	unsigned int	r_len;		/* Length of the window */
     24
     25	unsigned int	r_last_len;	/* Length of most recent alloc */
     26	unsigned int	r_last_start;	/* Start of most recent alloc */
     27	struct list_head	r_lru;	/* LRU list head */
     28
     29	unsigned int	r_flags;
     30};
     31
     32#define	OCFS2_RESV_FLAG_INUSE	0x01	/* Set when r_node is part of a btree */
     33#define	OCFS2_RESV_FLAG_TMP	0x02	/* Temporary reservation, will be
     34					 * destroyed immedately after use */
     35#define	OCFS2_RESV_FLAG_DIR	0x04	/* Reservation is for an unindexed
     36					 * directory btree */
     37
     38struct ocfs2_reservation_map {
     39	struct rb_root		m_reservations;
     40	char			*m_disk_bitmap;
     41
     42	struct ocfs2_super	*m_osb;
     43
     44	/* The following are not initialized to meaningful values until a disk
     45	 * bitmap is provided. */
     46	u32			m_bitmap_len;	/* Number of valid
     47						 * bits available */
     48
     49	struct list_head	m_lru;		/* LRU of reservations
     50						 * structures. */
     51
     52};
     53
     54void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv);
     55
     56#define OCFS2_RESV_TYPES	(OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR)
     57void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
     58			 unsigned int flags);
     59
     60int ocfs2_dir_resv_allowed(struct ocfs2_super *osb);
     61
     62/**
     63 * ocfs2_resv_discard() - truncate a reservation
     64 * @resmap:
     65 * @resv: the reservation to truncate.
     66 *
     67 * After this function is called, the reservation will be empty, and
     68 * unlinked from the rbtree.
     69 */
     70void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
     71			struct ocfs2_alloc_reservation *resv);
     72
     73
     74/**
     75 * ocfs2_resmap_init() - Initialize fields of a reservations bitmap
     76 * @osb: struct ocfs2_super to be saved in resmap
     77 * @resmap: struct ocfs2_reservation_map to initialize
     78 */
     79void ocfs2_resmap_init(struct ocfs2_super *osb,
     80		      struct ocfs2_reservation_map *resmap);
     81
     82/**
     83 * ocfs2_resmap_restart() - "restart" a reservation bitmap
     84 * @resmap: reservations bitmap
     85 * @clen: Number of valid bits in the bitmap
     86 * @disk_bitmap: the disk bitmap this resmap should refer to.
     87 *
     88 * Re-initialize the parameters of a reservation bitmap. This is
     89 * useful for local alloc window slides.
     90 *
     91 * This function will call ocfs2_trunc_resv against all existing
     92 * reservations. A future version will recalculate existing
     93 * reservations based on the new bitmap.
     94 */
     95void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
     96			  unsigned int clen, char *disk_bitmap);
     97
     98/**
     99 * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure
    100 * @resmap: the struct ocfs2_reservation_map to uninitialize
    101 */
    102void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap);
    103
    104/**
    105 * ocfs2_resmap_resv_bits() - Return still-valid reservation bits
    106 * @resmap: reservations bitmap
    107 * @resv: reservation to base search from
    108 * @cstart: start of proposed allocation
    109 * @clen: length (in clusters) of proposed allocation
    110 *
    111 * Using the reservation data from resv, this function will compare
    112 * resmap and resmap->m_disk_bitmap to determine what part (if any) of
    113 * the reservation window is still clear to use. If resv is empty,
    114 * this function will try to allocate a window for it.
    115 *
    116 * On success, zero is returned and the valid allocation area is set in cstart
    117 * and clen.
    118 *
    119 * Returns -ENOSPC if reservations are disabled.
    120 */
    121int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
    122			   struct ocfs2_alloc_reservation *resv,
    123			   int *cstart, int *clen);
    124
    125/**
    126 * ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used.
    127 * @resmap: reservations bitmap
    128 * @resv: optional reservation to recalulate based on new bitmap
    129 * @cstart: start of allocation in clusters
    130 * @clen: end of allocation in clusters.
    131 *
    132 * Tell the reservation code that bits were used to fulfill allocation in
    133 * resmap. The bits don't have to have been part of any existing
    134 * reservation. But we must always call this function when bits are claimed.
    135 * Internally, the reservations code will use this information to mark the
    136 * reservations bitmap. If resv is passed, it's next allocation window will be
    137 * calculated. It also expects that 'cstart' is the same as we passed back
    138 * from ocfs2_resmap_resv_bits().
    139 */
    140void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
    141			       struct ocfs2_alloc_reservation *resv,
    142			       u32 cstart, u32 clen);
    143
    144#endif	/* OCFS2_RESERVATIONS_H */