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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright (C) 2011-2017 Red Hat, Inc.4 *5 * This file is released under the GPL.6 */7 8#ifndef DM_BIO_PRISON_V2_H9#define DM_BIO_PRISON_V2_H10 11#include "persistent-data/dm-block-manager.h" /* FIXME: for dm_block_t */12#include "dm-thin-metadata.h" /* FIXME: for dm_thin_id */13 14#include <linux/bio.h>15#include <linux/rbtree.h>16#include <linux/workqueue.h>17 18/*----------------------------------------------------------------*/19 20int dm_bio_prison_init_v2(void);21void dm_bio_prison_exit_v2(void);22 23/*24 * Sometimes we can't deal with a bio straight away. We put them in prison25 * where they can't cause any mischief. Bios are put in a cell identified26 * by a key, multiple bios can be in the same cell. When the cell is27 * subsequently unlocked the bios become available.28 */29struct dm_bio_prison_v2;30 31/*32 * Keys define a range of blocks within either a virtual or physical33 * device.34 */35struct dm_cell_key_v2 {36 int virtual;37 dm_thin_id dev;38 dm_block_t block_begin, block_end;39};40 41/*42 * Treat this as opaque, only in header so callers can manage allocation43 * themselves.44 */45struct dm_bio_prison_cell_v2 {46 // FIXME: pack these47 bool exclusive_lock;48 unsigned int exclusive_level;49 unsigned int shared_count;50 struct work_struct *quiesce_continuation;51 52 struct rb_node node;53 struct dm_cell_key_v2 key;54 struct bio_list bios;55};56 57struct dm_bio_prison_v2 *dm_bio_prison_create_v2(struct workqueue_struct *wq);58void dm_bio_prison_destroy_v2(struct dm_bio_prison_v2 *prison);59 60/*61 * These two functions just wrap a mempool. This is a transitory step:62 * Eventually all bio prison clients should manage their own cell memory.63 *64 * Like mempool_alloc(), dm_bio_prison_alloc_cell_v2() can only fail if called65 * in interrupt context or passed GFP_NOWAIT.66 */67struct dm_bio_prison_cell_v2 *dm_bio_prison_alloc_cell_v2(struct dm_bio_prison_v2 *prison,68 gfp_t gfp);69void dm_bio_prison_free_cell_v2(struct dm_bio_prison_v2 *prison,70 struct dm_bio_prison_cell_v2 *cell);71 72/*73 * Shared locks have a bio associated with them.74 *75 * If the lock is granted the caller can continue to use the bio, and must76 * call dm_cell_put_v2() to drop the reference count when finished using it.77 *78 * If the lock cannot be granted then the bio will be tracked within the79 * cell, and later given to the holder of the exclusive lock.80 *81 * See dm_cell_lock_v2() for discussion of the lock_level parameter.82 *83 * Compare *cell_result with cell_prealloc to see if the prealloc was used.84 * If cell_prealloc was used then inmate wasn't added to it.85 *86 * Returns true if the lock is granted.87 */88bool dm_cell_get_v2(struct dm_bio_prison_v2 *prison,89 struct dm_cell_key_v2 *key,90 unsigned int lock_level,91 struct bio *inmate,92 struct dm_bio_prison_cell_v2 *cell_prealloc,93 struct dm_bio_prison_cell_v2 **cell_result);94 95/*96 * Decrement the shared reference count for the lock. Returns true if97 * returning ownership of the cell (ie. you should free it).98 */99bool dm_cell_put_v2(struct dm_bio_prison_v2 *prison,100 struct dm_bio_prison_cell_v2 *cell);101 102/*103 * Locks a cell. No associated bio. Exclusive locks get priority. These104 * locks constrain whether the io locks are granted according to level.105 *106 * Shared locks will still be granted if the lock_level is > (not = to) the107 * exclusive lock level.108 *109 * If an _exclusive_ lock is already held then -EBUSY is returned.110 *111 * Return values:112 * < 0 - error113 * 0 - locked; no quiescing needed114 * 1 - locked; quiescing needed115 */116int dm_cell_lock_v2(struct dm_bio_prison_v2 *prison,117 struct dm_cell_key_v2 *key,118 unsigned int lock_level,119 struct dm_bio_prison_cell_v2 *cell_prealloc,120 struct dm_bio_prison_cell_v2 **cell_result);121 122void dm_cell_quiesce_v2(struct dm_bio_prison_v2 *prison,123 struct dm_bio_prison_cell_v2 *cell,124 struct work_struct *continuation);125 126/*127 * Promotes an _exclusive_ lock to a higher lock level.128 *129 * Return values:130 * < 0 - error131 * 0 - promoted; no quiescing needed132 * 1 - promoted; quiescing needed133 */134int dm_cell_lock_promote_v2(struct dm_bio_prison_v2 *prison,135 struct dm_bio_prison_cell_v2 *cell,136 unsigned int new_lock_level);137 138/*139 * Adds any held bios to the bio list.140 *141 * There may be shared locks still held at this point even if you quiesced142 * (ie. different lock levels).143 *144 * Returns true if returning ownership of the cell (ie. you should free145 * it).146 */147bool dm_cell_unlock_v2(struct dm_bio_prison_v2 *prison,148 struct dm_bio_prison_cell_v2 *cell,149 struct bio_list *bios);150 151/*----------------------------------------------------------------*/152 153#endif154