13bd94003SHeinz Mauelshagen /* SPDX-License-Identifier: GPL-2.0-only */ 2afa53df8SMikulas Patocka /* 3afa53df8SMikulas Patocka * Copyright (C) 2009-2011 Red Hat, Inc. 4afa53df8SMikulas Patocka * 5afa53df8SMikulas Patocka * Author: Mikulas Patocka <mpatocka@redhat.com> 6afa53df8SMikulas Patocka * 7afa53df8SMikulas Patocka * This file is released under the GPL. 8afa53df8SMikulas Patocka */ 9afa53df8SMikulas Patocka 10afa53df8SMikulas Patocka #ifndef _LINUX_DM_BUFIO_H 11afa53df8SMikulas Patocka #define _LINUX_DM_BUFIO_H 12afa53df8SMikulas Patocka 13afa53df8SMikulas Patocka #include <linux/blkdev.h> 14afa53df8SMikulas Patocka #include <linux/types.h> 15afa53df8SMikulas Patocka 16afa53df8SMikulas Patocka /*----------------------------------------------------------------*/ 17afa53df8SMikulas Patocka 18afa53df8SMikulas Patocka struct dm_bufio_client; 19afa53df8SMikulas Patocka struct dm_buffer; 20afa53df8SMikulas Patocka 21afa53df8SMikulas Patocka /* 22b32d4582SNathan Huckleberry * Flags for dm_bufio_client_create 23b32d4582SNathan Huckleberry */ 24b32d4582SNathan Huckleberry #define DM_BUFIO_CLIENT_NO_SLEEP 0x1 25b32d4582SNathan Huckleberry 26b32d4582SNathan Huckleberry /* 27afa53df8SMikulas Patocka * Create a buffered IO cache on a given device 28afa53df8SMikulas Patocka */ 29afa53df8SMikulas Patocka struct dm_bufio_client * 3086a3238cSHeinz Mauelshagen dm_bufio_client_create(struct block_device *bdev, unsigned int block_size, 3186a3238cSHeinz Mauelshagen unsigned int reserved_buffers, unsigned int aux_size, 32afa53df8SMikulas Patocka void (*alloc_callback)(struct dm_buffer *), 330fcb100dSNathan Huckleberry void (*write_callback)(struct dm_buffer *), 340fcb100dSNathan Huckleberry unsigned int flags); 35afa53df8SMikulas Patocka 36afa53df8SMikulas Patocka /* 37afa53df8SMikulas Patocka * Release a buffered IO cache. 38afa53df8SMikulas Patocka */ 39afa53df8SMikulas Patocka void dm_bufio_client_destroy(struct dm_bufio_client *c); 40afa53df8SMikulas Patocka 41*d4830012SLi Lingfeng void dm_bufio_client_reset(struct dm_bufio_client *c); 42*d4830012SLi Lingfeng 43afa53df8SMikulas Patocka /* 44afa53df8SMikulas Patocka * Set the sector range. 45afa53df8SMikulas Patocka * When this function is called, there must be no I/O in progress on the bufio 46afa53df8SMikulas Patocka * client. 47afa53df8SMikulas Patocka */ 48afa53df8SMikulas Patocka void dm_bufio_set_sector_offset(struct dm_bufio_client *c, sector_t start); 49afa53df8SMikulas Patocka 50afa53df8SMikulas Patocka /* 51afa53df8SMikulas Patocka * WARNING: to avoid deadlocks, these conditions are observed: 52afa53df8SMikulas Patocka * 53afa53df8SMikulas Patocka * - At most one thread can hold at most "reserved_buffers" simultaneously. 54afa53df8SMikulas Patocka * - Each other threads can hold at most one buffer. 55afa53df8SMikulas Patocka * - Threads which call only dm_bufio_get can hold unlimited number of 56afa53df8SMikulas Patocka * buffers. 57afa53df8SMikulas Patocka */ 58afa53df8SMikulas Patocka 59afa53df8SMikulas Patocka /* 60afa53df8SMikulas Patocka * Read a given block from disk. Returns pointer to data. Returns a 61afa53df8SMikulas Patocka * pointer to dm_buffer that can be used to release the buffer or to make 62afa53df8SMikulas Patocka * it dirty. 63afa53df8SMikulas Patocka */ 64afa53df8SMikulas Patocka void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, 65afa53df8SMikulas Patocka struct dm_buffer **bp); 66afa53df8SMikulas Patocka 67afa53df8SMikulas Patocka /* 68afa53df8SMikulas Patocka * Like dm_bufio_read, but return buffer from cache, don't read 69afa53df8SMikulas Patocka * it. If the buffer is not in the cache, return NULL. 70afa53df8SMikulas Patocka */ 71afa53df8SMikulas Patocka void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, 72afa53df8SMikulas Patocka struct dm_buffer **bp); 73afa53df8SMikulas Patocka 74afa53df8SMikulas Patocka /* 75afa53df8SMikulas Patocka * Like dm_bufio_read, but don't read anything from the disk. It is 76afa53df8SMikulas Patocka * expected that the caller initializes the buffer and marks it dirty. 77afa53df8SMikulas Patocka */ 78afa53df8SMikulas Patocka void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, 79afa53df8SMikulas Patocka struct dm_buffer **bp); 80afa53df8SMikulas Patocka 81afa53df8SMikulas Patocka /* 82afa53df8SMikulas Patocka * Prefetch the specified blocks to the cache. 83afa53df8SMikulas Patocka * The function starts to read the blocks and returns without waiting for 84afa53df8SMikulas Patocka * I/O to finish. 85afa53df8SMikulas Patocka */ 86afa53df8SMikulas Patocka void dm_bufio_prefetch(struct dm_bufio_client *c, 8786a3238cSHeinz Mauelshagen sector_t block, unsigned int n_blocks); 88afa53df8SMikulas Patocka 89afa53df8SMikulas Patocka /* 90afa53df8SMikulas Patocka * Release a reference obtained with dm_bufio_{read,get,new}. The data 91afa53df8SMikulas Patocka * pointer and dm_buffer pointer is no longer valid after this call. 92afa53df8SMikulas Patocka */ 93afa53df8SMikulas Patocka void dm_bufio_release(struct dm_buffer *b); 94afa53df8SMikulas Patocka 95afa53df8SMikulas Patocka /* 96afa53df8SMikulas Patocka * Mark a buffer dirty. It should be called after the buffer is modified. 97afa53df8SMikulas Patocka * 98afa53df8SMikulas Patocka * In case of memory pressure, the buffer may be written after 99afa53df8SMikulas Patocka * dm_bufio_mark_buffer_dirty, but before dm_bufio_write_dirty_buffers. So 100afa53df8SMikulas Patocka * dm_bufio_write_dirty_buffers guarantees that the buffer is on-disk but 101afa53df8SMikulas Patocka * the actual writing may occur earlier. 102afa53df8SMikulas Patocka */ 103afa53df8SMikulas Patocka void dm_bufio_mark_buffer_dirty(struct dm_buffer *b); 104afa53df8SMikulas Patocka 105afa53df8SMikulas Patocka /* 106afa53df8SMikulas Patocka * Mark a part of the buffer dirty. 107afa53df8SMikulas Patocka * 108afa53df8SMikulas Patocka * The specified part of the buffer is scheduled to be written. dm-bufio may 109afa53df8SMikulas Patocka * write the specified part of the buffer or it may write a larger superset. 110afa53df8SMikulas Patocka */ 111afa53df8SMikulas Patocka void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b, 11286a3238cSHeinz Mauelshagen unsigned int start, unsigned int end); 113afa53df8SMikulas Patocka 114afa53df8SMikulas Patocka /* 115afa53df8SMikulas Patocka * Initiate writing of dirty buffers, without waiting for completion. 116afa53df8SMikulas Patocka */ 117afa53df8SMikulas Patocka void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c); 118afa53df8SMikulas Patocka 119afa53df8SMikulas Patocka /* 120afa53df8SMikulas Patocka * Write all dirty buffers. Guarantees that all dirty buffers created prior 121afa53df8SMikulas Patocka * to this call are on disk when this call exits. 122afa53df8SMikulas Patocka */ 123afa53df8SMikulas Patocka int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c); 124afa53df8SMikulas Patocka 125afa53df8SMikulas Patocka /* 126afa53df8SMikulas Patocka * Send an empty write barrier to the device to flush hardware disk cache. 127afa53df8SMikulas Patocka */ 128afa53df8SMikulas Patocka int dm_bufio_issue_flush(struct dm_bufio_client *c); 129afa53df8SMikulas Patocka 130afa53df8SMikulas Patocka /* 1316fbeb004SMikulas Patocka * Send a discard request to the underlying device. 1326fbeb004SMikulas Patocka */ 1336fbeb004SMikulas Patocka int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count); 1346fbeb004SMikulas Patocka 1356fbeb004SMikulas Patocka /* 136afa53df8SMikulas Patocka * Free the given buffer. 137afa53df8SMikulas Patocka * This is just a hint, if the buffer is in use or dirty, this function 138afa53df8SMikulas Patocka * does nothing. 139afa53df8SMikulas Patocka */ 140afa53df8SMikulas Patocka void dm_bufio_forget(struct dm_bufio_client *c, sector_t block); 141afa53df8SMikulas Patocka 142afa53df8SMikulas Patocka /* 14333a18062SMikulas Patocka * Free the given range of buffers. 14433a18062SMikulas Patocka * This is just a hint, if the buffer is in use or dirty, this function 14533a18062SMikulas Patocka * does nothing. 14633a18062SMikulas Patocka */ 14733a18062SMikulas Patocka void dm_bufio_forget_buffers(struct dm_bufio_client *c, sector_t block, sector_t n_blocks); 14833a18062SMikulas Patocka 14933a18062SMikulas Patocka /* 150afa53df8SMikulas Patocka * Set the minimum number of buffers before cleanup happens. 151afa53df8SMikulas Patocka */ 15286a3238cSHeinz Mauelshagen void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned int n); 153afa53df8SMikulas Patocka 15486a3238cSHeinz Mauelshagen unsigned int dm_bufio_get_block_size(struct dm_bufio_client *c); 155afa53df8SMikulas Patocka sector_t dm_bufio_get_device_size(struct dm_bufio_client *c); 1569b594826SMikulas Patocka struct dm_io_client *dm_bufio_get_dm_io_client(struct dm_bufio_client *c); 157afa53df8SMikulas Patocka sector_t dm_bufio_get_block_number(struct dm_buffer *b); 158afa53df8SMikulas Patocka void *dm_bufio_get_block_data(struct dm_buffer *b); 159afa53df8SMikulas Patocka void *dm_bufio_get_aux_data(struct dm_buffer *b); 160afa53df8SMikulas Patocka struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b); 161afa53df8SMikulas Patocka 162afa53df8SMikulas Patocka /*----------------------------------------------------------------*/ 163afa53df8SMikulas Patocka 164afa53df8SMikulas Patocka #endif 165