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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dm-bio-prison-v2.h (4611B)

      1/*
      2 * Copyright (C) 2011-2017 Red Hat, Inc.
      3 *
      4 * This file is released under the GPL.
      5 */
      6
      7#ifndef DM_BIO_PRISON_V2_H
      8#define DM_BIO_PRISON_V2_H
      9
     10#include "persistent-data/dm-block-manager.h" /* FIXME: for dm_block_t */
     11#include "dm-thin-metadata.h" /* FIXME: for dm_thin_id */
     12
     13#include <linux/bio.h>
     14#include <linux/rbtree.h>
     15#include <linux/workqueue.h>
     16
     17/*----------------------------------------------------------------*/
     18
     19int dm_bio_prison_init_v2(void);
     20void dm_bio_prison_exit_v2(void);
     21
     22/*
     23 * Sometimes we can't deal with a bio straight away.  We put them in prison
     24 * where they can't cause any mischief.  Bios are put in a cell identified
     25 * by a key, multiple bios can be in the same cell.  When the cell is
     26 * subsequently unlocked the bios become available.
     27 */
     28struct dm_bio_prison_v2;
     29
     30/*
     31 * Keys define a range of blocks within either a virtual or physical
     32 * device.
     33 */
     34struct dm_cell_key_v2 {
     35	int virtual;
     36	dm_thin_id dev;
     37	dm_block_t block_begin, block_end;
     38};
     39
     40/*
     41 * Treat this as opaque, only in header so callers can manage allocation
     42 * themselves.
     43 */
     44struct dm_bio_prison_cell_v2 {
     45	// FIXME: pack these
     46	bool exclusive_lock;
     47	unsigned exclusive_level;
     48	unsigned shared_count;
     49	struct work_struct *quiesce_continuation;
     50
     51	struct rb_node node;
     52	struct dm_cell_key_v2 key;
     53	struct bio_list bios;
     54};
     55
     56struct dm_bio_prison_v2 *dm_bio_prison_create_v2(struct workqueue_struct *wq);
     57void dm_bio_prison_destroy_v2(struct dm_bio_prison_v2 *prison);
     58
     59/*
     60 * These two functions just wrap a mempool.  This is a transitory step:
     61 * Eventually all bio prison clients should manage their own cell memory.
     62 *
     63 * Like mempool_alloc(), dm_bio_prison_alloc_cell_v2() can only fail if called
     64 * in interrupt context or passed GFP_NOWAIT.
     65 */
     66struct dm_bio_prison_cell_v2 *dm_bio_prison_alloc_cell_v2(struct dm_bio_prison_v2 *prison,
     67						    gfp_t gfp);
     68void dm_bio_prison_free_cell_v2(struct dm_bio_prison_v2 *prison,
     69				struct dm_bio_prison_cell_v2 *cell);
     70
     71/*
     72 * Shared locks have a bio associated with them.
     73 *
     74 * If the lock is granted the caller can continue to use the bio, and must
     75 * call dm_cell_put_v2() to drop the reference count when finished using it.
     76 *
     77 * If the lock cannot be granted then the bio will be tracked within the
     78 * cell, and later given to the holder of the exclusive lock.
     79 *
     80 * See dm_cell_lock_v2() for discussion of the lock_level parameter.
     81 *
     82 * Compare *cell_result with cell_prealloc to see if the prealloc was used.
     83 * If cell_prealloc was used then inmate wasn't added to it.
     84 *
     85 * Returns true if the lock is granted.
     86 */
     87bool dm_cell_get_v2(struct dm_bio_prison_v2 *prison,
     88		    struct dm_cell_key_v2 *key,
     89		    unsigned lock_level,
     90		    struct bio *inmate,
     91		    struct dm_bio_prison_cell_v2 *cell_prealloc,
     92		    struct dm_bio_prison_cell_v2 **cell_result);
     93
     94/*
     95 * Decrement the shared reference count for the lock.  Returns true if
     96 * returning ownership of the cell (ie. you should free it).
     97 */
     98bool dm_cell_put_v2(struct dm_bio_prison_v2 *prison,
     99		    struct dm_bio_prison_cell_v2 *cell);
    100
    101/*
    102 * Locks a cell.  No associated bio.  Exclusive locks get priority.  These
    103 * locks constrain whether the io locks are granted according to level.
    104 *
    105 * Shared locks will still be granted if the lock_level is > (not = to) the
    106 * exclusive lock level.
    107 *
    108 * If an _exclusive_ lock is already held then -EBUSY is returned.
    109 *
    110 * Return values:
    111 *  < 0 - error
    112 *  0   - locked; no quiescing needed
    113 *  1   - locked; quiescing needed
    114 */
    115int dm_cell_lock_v2(struct dm_bio_prison_v2 *prison,
    116		    struct dm_cell_key_v2 *key,
    117		    unsigned lock_level,
    118		    struct dm_bio_prison_cell_v2 *cell_prealloc,
    119		    struct dm_bio_prison_cell_v2 **cell_result);
    120
    121void dm_cell_quiesce_v2(struct dm_bio_prison_v2 *prison,
    122			struct dm_bio_prison_cell_v2 *cell,
    123			struct work_struct *continuation);
    124
    125/*
    126 * Promotes an _exclusive_ lock to a higher lock level.
    127 *
    128 * Return values:
    129 *  < 0 - error
    130 *  0   - promoted; no quiescing needed
    131 *  1   - promoted; quiescing needed
    132 */
    133int dm_cell_lock_promote_v2(struct dm_bio_prison_v2 *prison,
    134			    struct dm_bio_prison_cell_v2 *cell,
    135			    unsigned new_lock_level);
    136
    137/*
    138 * Adds any held bios to the bio list.
    139 *
    140 * There may be shared locks still held at this point even if you quiesced
    141 * (ie. different lock levels).
    142 *
    143 * Returns true if returning ownership of the cell (ie. you should free
    144 * it).
    145 */
    146bool dm_cell_unlock_v2(struct dm_bio_prison_v2 *prison,
    147		       struct dm_bio_prison_cell_v2 *cell,
    148		       struct bio_list *bios);
    149
    150/*----------------------------------------------------------------*/
    151
    152#endif