drivers/nvdimm/btt.h

   1 /*
   2  * Block Translation Table library
   3  * Copyright (c) 2014-2015, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  */
  14
  15 #ifndef _LINUX_BTT_H
  16 #define _LINUX_BTT_H
  17
  18 #include <linux/types.h>
  19
  20 #define BTT_SIG_LEN 16
  21 #define BTT_SIG "BTT_ARENA_INFO\0"
  22 #define MAP_ENT_SIZE 4
  23 #define MAP_TRIM_SHIFT 31
  24 #define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
  25 #define MAP_ERR_SHIFT 30
  26 #define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
  27 #define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
  28 #define MAP_ENT_NORMAL 0xC0000000
  29 #define LOG_ENT_SIZE sizeof(struct log_entry)
  30 #define ARENA_MIN_SIZE (1UL << 24)      /* 16 MB */
  31 #define ARENA_MAX_SIZE (1ULL << 39)     /* 512 GB */
  32 #define RTT_VALID (1UL << 31)
  33 #define RTT_INVALID 0
  34 #define BTT_PG_SIZE 4096
  35 #define BTT_DEFAULT_NFREE ND_MAX_LANES
  36 #define LOG_SEQ_INIT 1
  37
  38 #define IB_FLAG_ERROR 0x00000001
  39 #define IB_FLAG_ERROR_MASK 0x00000001
  40
  41 enum btt_init_state {
  42         INIT_UNCHECKED = 0,
  43         INIT_NOTFOUND,
  44         INIT_READY
  45 };
  46
  47 struct log_entry {
  48         __le32 lba;
  49         __le32 old_map;
  50         __le32 new_map;
  51         __le32 seq;
  52         __le64 padding[2];
  53 };
  54
  55 struct btt_sb {
  56         u8 signature[BTT_SIG_LEN];
  57         u8 uuid[16];
  58         u8 parent_uuid[16];
  59         __le32 flags;
  60         __le16 version_major;
  61         __le16 version_minor;
  62         __le32 external_lbasize;
  63         __le32 external_nlba;
  64         __le32 internal_lbasize;
  65         __le32 internal_nlba;
  66         __le32 nfree;
  67         __le32 infosize;
  68         __le64 nextoff;
  69         __le64 dataoff;
  70         __le64 mapoff;
  71         __le64 logoff;
  72         __le64 info2off;
  73         u8 padding[3968];
  74         __le64 checksum;
  75 };
  76
  77 struct free_entry {
  78         u32 block;
  79         u8 sub;
  80         u8 seq;
  81 };
  82
  83 struct aligned_lock {
  84         union {
  85                 spinlock_t lock;
  86                 u8 cacheline_padding[L1_CACHE_BYTES];
  87         };
  88 };
  89
  90 /**
  91  * struct arena_info - handle for an arena
  92  * @size:               Size in bytes this arena occupies on the raw device.
  93  *                      This includes arena metadata.
  94  * @external_lba_start: The first external LBA in this arena.
  95  * @internal_nlba:      Number of internal blocks available in the arena
  96  *                      including nfree reserved blocks
  97  * @internal_lbasize:   Internal and external lba sizes may be different as
  98  *                      we can round up 'odd' external lbasizes such as 520B
  99  *                      to be aligned.
 100  * @external_nlba:      Number of blocks contributed by the arena to the number
 101  *                      reported to upper layers. (internal_nlba - nfree)
 102  * @external_lbasize:   LBA size as exposed to upper layers.
 103  * @nfree:              A reserve number of 'free' blocks that is used to
 104  *                      handle incoming writes.
 105  * @version_major:      Metadata layout version major.
 106  * @version_minor:      Metadata layout version minor.
 107  * @nextoff:            Offset in bytes to the start of the next arena.
 108  * @infooff:            Offset in bytes to the info block of this arena.
 109  * @dataoff:            Offset in bytes to the data area of this arena.
 110  * @mapoff:             Offset in bytes to the map area of this arena.
 111  * @logoff:             Offset in bytes to the log area of this arena.
 112  * @info2off:           Offset in bytes to the backup info block of this arena.
 113  * @freelist:           Pointer to in-memory list of free blocks
 114  * @rtt:                Pointer to in-memory "Read Tracking Table"
 115  * @map_locks:          Spinlocks protecting concurrent map writes
 116  * @nd_btt:             Pointer to parent nd_btt structure.
 117  * @list:               List head for list of arenas
 118  * @debugfs_dir:        Debugfs dentry
 119  * @flags:              Arena flags - may signify error states.
 120  *
 121  * arena_info is a per-arena handle. Once an arena is narrowed down for an
 122  * IO, this struct is passed around for the duration of the IO.
 123  */
 124 struct arena_info {
 125         u64 size;                       /* Total bytes for this arena */
 126         u64 external_lba_start;
 127         u32 internal_nlba;
 128         u32 internal_lbasize;
 129         u32 external_nlba;
 130         u32 external_lbasize;
 131         u32 nfree;
 132         u16 version_major;
 133         u16 version_minor;
 134         /* Byte offsets to the different on-media structures */
 135         u64 nextoff;
 136         u64 infooff;
 137         u64 dataoff;
 138         u64 mapoff;
 139         u64 logoff;
 140         u64 info2off;
 141         /* Pointers to other in-memory structures for this arena */
 142         struct free_entry *freelist;
 143         u32 *rtt;
 144         struct aligned_lock *map_locks;
 145         struct nd_btt *nd_btt;
 146         struct list_head list;
 147         struct dentry *debugfs_dir;
 148         /* Arena flags */
 149         u32 flags;
 150 };
 151
 152 /**
 153  * struct btt - handle for a BTT instance
 154  * @btt_disk:           Pointer to the gendisk for BTT device
 155  * @btt_queue:          Pointer to the request queue for the BTT device
 156  * @arena_list:         Head of the list of arenas
 157  * @debugfs_dir:        Debugfs dentry
 158  * @nd_btt:             Parent nd_btt struct
 159  * @nlba:               Number of logical blocks exposed to the upper layers
 160  *                      after removing the amount of space needed by metadata
 161  * @rawsize:            Total size in bytes of the available backing device
 162  * @lbasize:            LBA size as requested and presented to upper layers.
 163  *                      This is sector_size + size of any metadata.
 164  * @sector_size:        The Linux sector size - 512 or 4096
 165  * @lanes:              Per-lane spinlocks
 166  * @init_lock:          Mutex used for the BTT initialization
 167  * @init_state:         Flag describing the initialization state for the BTT
 168  * @num_arenas:         Number of arenas in the BTT instance
 169  */
 170 struct btt {
 171         struct gendisk *btt_disk;
 172         struct request_queue *btt_queue;
 173         struct list_head arena_list;
 174         struct dentry *debugfs_dir;
 175         struct nd_btt *nd_btt;
 176         u64 nlba;
 177         unsigned long long rawsize;
 178         u32 lbasize;
 179         u32 sector_size;
 180         struct nd_region *nd_region;
 181         struct mutex init_lock;
 182         int init_state;
 183         int num_arenas;
 184 };
 185
 186 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
 187
 188 #endif