mars/kernel/mars_if.h

130 lines
3.1 KiB
C

/*
* MARS Long Distance Replication Software
*
* This file is part of MARS project: http://schoebel.github.io/mars/
*
* Copyright (C) 2010-2014 Thomas Schoebel-Theuer
* Copyright (C) 2011-2014 1&1 Internet AG
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MARS_IF_H
#define MARS_IF_H
#include "lib_limiter.h"
#include <linux/semaphore.h>
#define MARS_MAX_SEGMENT_SIZE (PAGE_SIZE)
#define MAX_BIO 32
//#define USE_TIMER (HZ/10) // use this ONLY for debugging
///////////////////////// global tuning ////////////////////////
extern int if_nr_requests;
extern int if_throttle_start_size; // in kb
extern struct mars_limiter if_throttle;
/////////////////////////////////////////////////
/* I don't want to enhance / intrude into struct bio for compatibility reasons
* (support for a variety of kernel versions).
* The following is just a silly workaround which could be removed again.
*/
struct bio_wrapper {
struct bio *bio;
atomic_t bi_comp_cnt;
unsigned long start_time;
};
struct if_mref_aspect {
GENERIC_ASPECT(mref);
struct list_head plug_head;
struct list_head hash_head;
int hash_index;
int bio_count;
int current_len;
int max_len;
struct page *orig_page;
struct bio_wrapper *orig_biow[MAX_BIO];
struct if_input *input;
};
struct if_hash_anchor;
struct if_input {
MARS_INPUT(if);
// TODO: move this to if_brick (better systematics)
struct list_head plug_anchor;
struct request_queue *q;
struct gendisk *disk;
struct block_device *bdev;
#ifdef USE_TIMER
struct timer_list timer;
#endif
loff_t capacity;
atomic_t plugged_count;
/* debugging statistics */
#ifdef CONFIG_MARS_DEBUG
atomic_t total_reada_count;
atomic_t total_read_count;
atomic_t total_write_count;
atomic_t total_empty_count;
atomic_t total_fire_count;
atomic_t total_skip_sync_count;
atomic_t total_mref_read_count;
atomic_t total_mref_write_count;
#endif
/* private */
#ifdef MARS_HAS_OLD_QUEUE_LOCK
spinlock_t req_lock;
#endif
struct semaphore kick_sem;
struct if_hash_anchor *hash_table;
};
struct if_output {
MARS_OUTPUT(if);
};
struct if_brick {
MARS_BRICK(if);
// parameters
loff_t real_size;
loff_t max_size;
loff_t dev_size;
int max_plugged;
int readahead;
bool skip_sync;
// inspectable
atomic_t open_count;
atomic_t read_flying_count;
atomic_t write_flying_count;
struct lamport_time completion_stamp;
struct mars_limiter io_limiter;
int error_code;
// private
struct semaphore switch_sem;
struct say_channel *say_channel;
struct mars_info info;
};
MARS_TYPES(if);
#endif