blob: c586bcdb5190b1c9f6447cb9a380568a03840988 [file] [log] [blame]
/*
* Block Translation Table
* Copyright (c) 2014-2015, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*/
#include <linux/highmem.h>
#include <linux/debugfs.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/hdreg.h>
#include <linux/genhd.h>
#include <linux/sizes.h>
#include <linux/ndctl.h>
#include <linux/fs.h>
#include <linux/nd.h>
#include <linux/backing-dev.h>
#include "btt.h"
#include "nd.h"
enum log_ent_request {
LOG_NEW_ENT = 0,
LOG_OLD_ENT
};
static struct device *to_dev(struct arena_info *arena)
{
return &arena->nd_btt->dev;
}
static u64 adjust_initial_offset(struct nd_btt *nd_btt, u64 offset)
{
return offset + nd_btt->initial_offset;
}
static int arena_read_bytes(struct arena_info *arena, resource_size_t offset,
void *buf, size_t n, unsigned long flags)
{
struct nd_btt *nd_btt = arena->nd_btt;
struct nd_namespace_common *ndns = nd_btt->ndns;
/* arena offsets may be shifted from the base of the device */
offset = adjust_initial_offset(nd_btt, offset);
return nvdimm_read_bytes(ndns, offset, buf, n, flags);
}
static int arena_write_bytes(struct arena_info *arena, resource_size_t offset,
void *buf, size_t n, unsigned long flags)
{
struct nd_btt *nd_btt = arena->nd_btt;
struct nd_namespace_common *ndns = nd_btt->ndns;
/* arena offsets may be shifted from the base of the device */
offset = adjust_initial_offset(nd_btt, offset);
return nvdimm_write_bytes(ndns, offset, buf, n, flags);
}
static int btt_info_write(struct arena_info *arena, struct btt_sb *super)
{
int ret;
/*
* infooff and info2off should always be at least 512B aligned.
* We rely on that to make sure rw_bytes does error clearing
* correctly, so make sure that is the case.
*/
dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->infooff, 512),
"arena->infooff: %#llx is unaligned\n", arena->infooff);
dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->info2off, 512),
"arena->info2off: %#llx is unaligned\n", arena->info2off);
ret = arena_write_bytes(arena, arena->info2off, super,
sizeof(struct btt_sb), 0);
if (ret)
return ret;
return arena_write_bytes(arena, arena->infooff, super,
sizeof(struct btt_sb), 0);
}
static int btt_info_read(struct arena_info *arena, struct btt_sb *super)
{
return arena_read_bytes(arena, arena->infooff, super,
sizeof(struct btt_sb), 0);
}
/*
* 'raw' version of btt_map write
* Assumptions:
* mapping is in little-endian
* mapping contains 'E' and 'Z' flags as desired
*/
static int __btt_map_write(struct arena_info *arena, u32 lba, __le32 mapping,
unsigned long flags)
{
u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);
if (unlikely(lba >= arena->external_nlba))
dev_err_ratelimited(to_dev(arena),
"%s: lba %#x out of range (max: %#x)\n",
__func__, lba, arena->external_nlba);
return arena_write_bytes(arena, ns_off, &mapping, MAP_ENT_SIZE, flags);
}
static int btt_map_write(struct arena_info *arena, u32 lba, u32 mapping,
u32 z_flag, u32 e_flag, unsigned long rwb_flags)
{
u32 ze;
__le32 mapping_le;
/*
* This 'mapping' is supposed to be just the LBA mapping, without
* any flags set, so strip the flag bits.
*/
mapping = ent_lba(mapping);
ze = (z_flag << 1) + e_flag;
switch (ze) {
case 0:
/*
* We want to set neither of the Z or E flags, and
* in the actual layout, this means setting the bit
* positions of both to '1' to indicate a 'normal'
* map entry
*/
mapping |= MAP_ENT_NORMAL;
break;
case 1:
mapping |= (1 << MAP_ERR_SHIFT);
break;
case 2:
mapping |= (1 << MAP_TRIM_SHIFT);
break;
default:
/*
* The case where Z and E are both sent in as '1' could be
* construed as a valid 'normal' case, but we decide not to,
* to avoid confusion
*/
dev_err_ratelimited(to_dev(arena),
"Invalid use of Z and E flags\n");
return -EIO;
}
mapping_le = cpu_to_le32(mapping);
return __btt_map_write(arena, lba, mapping_le, rwb_flags);
}
static int btt_map_read(struct arena_info *arena, u32 lba, u32 *mapping,
int *trim, int *error, unsigned long rwb_flags)
{
int ret;
__le32 in;
u32 raw_mapping, postmap, ze, z_flag, e_flag;
u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);
if (unlikely(lba >= arena->external_nlba))
dev_err_ratelimited(to_dev(arena),
"%s: lba %#x out of range (max: %#x)\n",
__func__, lba, arena->external_nlba);
ret = arena_read_bytes(arena, ns_off, &in, MAP_ENT_SIZE, rwb_flags);
if (ret)
return ret;
raw_mapping = le32_to_cpu(in);
z_flag = ent_z_flag(raw_mapping);
e_flag = ent_e_flag(raw_mapping);
ze = (z_flag << 1) + e_flag;
postmap = ent_lba(raw_mapping);
/* Reuse the {z,e}_flag variables for *trim and *error */
z_flag = 0;
e_flag = 0;
switch (ze) {
case 0:
/* Initial state. Return postmap = premap */
*mapping = lba;
break;
case 1:
*mapping = postmap;
e_flag = 1;
break;
case 2:
*mapping = postmap;
z_flag = 1;
break;
case 3:
*mapping = postmap;
break;
default:
return -EIO;
}
if (trim)
*trim = z_flag;
if (error)
*error = e_flag;
return ret;
}
static int btt_log_group_read(struct arena_info *arena, u32 lane,
struct log_group *log)
{
return arena_read_bytes(arena,
arena->logoff + (lane * LOG_GRP_SIZE), log,
LOG_GRP_SIZE, 0);
}
static struct dentry *debugfs_root;
static void arena_debugfs_init(struct arena_info *a, struct dentry *parent,
int idx)
{
char dirname[32];
struct dentry *d;
/* If for some reason, parent bttN was not created, exit */
if (!parent)
return;
snprintf(dirname, 32, "arena%d", idx);
d = debugfs_create_dir(dirname, parent);
if (IS_ERR_OR_NULL(d))
return;
a->debugfs_dir = d;
debugfs_create_x64("size", S_IRUGO, d, &a->size);
debugfs_create_x64("external_lba_start", S_IRUGO, d,
&a->external_lba_start);
debugfs_create_x32("internal_nlba", S_IRUGO, d, &a->internal_nlba);
debugfs_create_u32("internal_lbasize", S_IRUGO, d,
&a->internal_lbasize);
debugfs_create_x32("external_nlba", S_IRUGO, d, &a->external_nlba);
debugfs_create_u32("external_lbasize", S_IRUGO, d,
&a->external_lbasize);
debugfs_create_u32("nfree", S_IRUGO, d, &a->nfree);
debugfs_create_u16("version_major", S_IRUGO, d, &a->version_major);
debugfs_create_u16("version_minor", S_IRUGO, d, &a->version_minor);
debugfs_create_x64("nextoff", S_IRUGO, d, &a->nextoff);
debugfs_create_x64("infooff", S_IRUGO, d, &a->infooff);
debugfs_create_x64("dataoff", S_IRUGO, d, &a->dataoff);
debugfs_create_x64("mapoff", S_IRUGO, d, &a->mapoff);
debugfs_create_x64("logoff", S_IRUGO, d, &a->logoff);
debugfs_create_x64("info2off", S_IRUGO, d, &a->info2off);
debugfs_create_x32("flags", S_IRUGO, d, &a->flags);
debugfs_create_u32("log_index_0", S_IRUGO, d, &a->log_index[0]);
debugfs_create_u32("log_index_1", S_IRUGO, d, &a->log_index[1]);
}
static void btt_debugfs_init(struct btt *btt)
{
int i = 0;
struct arena_info *arena;
btt->debugfs_dir = debugfs_create_dir(dev_name(&btt->nd_btt->dev),
debugfs_root);
if (IS_ERR_OR_NULL(btt->debugfs_dir))
return;
list_for_each_entry(arena, &btt->arena_list, list) {
arena_debugfs_init(arena, btt->debugfs_dir, i);
i++;
}
}
static u32 log_seq(struct log_group *log, int log_idx)
{
return le32_to_cpu(log->ent[log_idx].seq);
}
/*
* This function accepts two log entries, and uses the
* sequence number to find the 'older' entry.
* It also updates the sequence number in this old entry to
* make it the 'new' one if the mark_flag is set.
* Finally, it returns which of the entries was the older one.
*
* TODO The logic feels a bit kludge-y. make it better..
*/
static int btt_log_get_old(struct arena_info *a, struct log_group *log)
{
int idx0 = a->log_index[0];
int idx1 = a->log_index[1];
int old;
/*
* the first ever time this is seen, the entry goes into [0]
* the next time, the following logic works out to put this
* (next) entry into [1]
*/
if (log_seq(log, idx0) == 0) {
log->ent[idx0].seq = cpu_to_le32(1);
return 0;
}
if (log_seq(log, idx0) == log_seq(log, idx1))
return -EINVAL;
if (log_seq(log, idx0) + log_seq(log, idx1) > 5)
return -EINVAL;
if (log_seq(log, idx0) < log_seq(log, idx1)) {
if ((log_seq(log, idx1) - log_seq(log, idx0)) == 1)
old = 0;
else
old = 1;
} else {
if ((log_seq(log, idx0) - log_seq(log, idx1)) == 1)
old = 1;
else
old = 0;
}
return old;
}
/*
* This function copies the desired (old/new) log entry into ent if
* it is not NULL. It returns the sub-slot number (0 or 1)
* where the desired log entry was found. Negative return values
* indicate errors.
*/
static int btt_log_read(struct arena_info *arena, u32 lane,
struct log_entry *ent, int old_flag)
{
int ret;
int old_ent, ret_ent;
struct log_group log;
ret = btt_log_group_read(arena, lane, &log);
if (ret)
return -EIO;
old_ent = btt_log_get_old(arena, &log);
if (old_ent < 0 || old_ent > 1) {
dev_err(to_dev(arena),
"log corruption (%d): lane %d seq [%d, %d]\n",
old_ent, lane, log.ent[arena->log_index[0]].seq,
log.ent[arena->log_index[1]].seq);
/* TODO set error state? */
return -EIO;
}
ret_ent = (old_flag ? old_ent : (1 - old_ent));
if (ent != NULL)
memcpy(ent, &log.ent[arena->log_index[ret_ent]], LOG_ENT_SIZE);
return ret_ent;
}
/*
* This function commits a log entry to media
* It does _not_ prepare the freelist entry for the next write
* btt_flog_write is the wrapper for updating the freelist elements
*/
static int __btt_log_write(struct arena_info *arena, u32 lane,
u32 sub, struct log_entry *ent, unsigned long flags)
{
int ret;
u32 group_slot = arena->log_index[sub];
unsigned int log_half = LOG_ENT_SIZE / 2;
void *src = ent;
u64 ns_off;
ns_off = arena->logoff + (lane * LOG_GRP_SIZE) +
(group_slot * LOG_ENT_SIZE);
/* split the 16B write into atomic, durable halves */
ret = arena_write_bytes(arena, ns_off, src, log_half, flags);
if (ret)
return ret;
ns_off += log_half;
src += log_half;
return arena_write_bytes(arena, ns_off, src, log_half, flags);
}
static int btt_flog_write(struct arena_info *arena, u32 lane, u32 sub,
struct log_entry *ent)
{
int ret;
ret = __btt_log_write(arena, lane, sub, ent, NVDIMM_IO_ATOMIC);
if (ret)
return ret;
/* prepare the next free entry */
arena->freelist[lane].sub = 1 - arena->freelist[lane].sub;
if (++(arena->freelist[lane].seq) == 4)
arena->freelist[lane].seq = 1;
if (ent_e_flag(ent->old_map))
arena->freelist[lane].has_err = 1;
arena->freelist[lane].block = le32_to_cpu(ent_lba(ent->old_map));
return ret;
}
/*
* This function initializes the BTT map to the initial state, which is
* all-zeroes, and indicates an identity mapping
*/
static int btt_map_init(struct arena_info *arena)
{
int ret = -EINVAL;
void *zerobuf;
size_t offset = 0;
size_t chunk_size = SZ_2M;
size_t mapsize = arena->logoff - arena->mapoff;
zerobuf = kzalloc(chunk_size, GFP_KERNEL);
if (!zerobuf)
return -ENOMEM;
/*
* mapoff should always be at least 512B aligned. We rely on that to
* make sure rw_bytes does error clearing correctly, so make sure that
* is the case.
*/
dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->mapoff, 512),
"arena->mapoff: %#llx is unaligned\n", arena->mapoff);
while (mapsize) {
size_t size = min(mapsize, chunk_size);
dev_WARN_ONCE(to_dev(arena), size < 512,
"chunk size: %#zx is unaligned\n", size);
ret = arena_write_bytes(arena, arena->mapoff + offset, zerobuf,
size, 0);
if (ret)
goto free;
offset += size;
mapsize -= size;
cond_resched();
}
free:
kfree(zerobuf);
return ret;
}
/*
* This function initializes the BTT log with 'fake' entries pointing
* to the initial reserved set of blocks as being free
*/
static int btt_log_init(struct arena_info *arena)
{
size_t logsize = arena->info2off - arena->logoff;
size_t chunk_size = SZ_4K, offset = 0;
struct log_entry ent;
void *zerobuf;
int ret;
u32 i;
zerobuf = kzalloc(chunk_size, GFP_KERNEL);
if (!zerobuf)
return -ENOMEM;
/*
* logoff should always be at least 512B aligned. We rely on that to
* make sure rw_bytes does error clearing correctly, so make sure that
* is the case.
*/
dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->logoff, 512),
"arena->logoff: %#llx is unaligned\n", arena->logoff);
while (logsize) {
size_t size = min(logsize, chunk_size);
dev_WARN_ONCE(to_dev(arena), size < 512,
"chunk size: %#zx is unaligned\n", size);
ret = arena_write_bytes(arena, arena->logoff + offset, zerobuf,
size, 0);
if (ret)
goto free;
offset += size;
logsize -= size;
cond_resched();
}
for (i = 0; i < arena->nfree; i++) {
ent.lba = cpu_to_le32(i);
ent.old_map = cpu_to_le32(arena->external_nlba + i);
ent.new_map = cpu_to_le32(arena->external_nlba + i);
ent.seq = cpu_to_le32(LOG_SEQ_INIT);
ret = __btt_log_write(arena, i, 0, &ent, 0);
if (ret)
goto free;
}
free:
kfree(zerobuf);
return ret;
}
static u64 to_namespace_offset(struct arena_info *arena, u64 lba)
{
return arena->dataoff + ((u64)lba * arena->internal_lbasize);
}
static int arena_clear_freelist_error(struct arena_info *arena, u32 lane)
{
int ret = 0;
if (arena->freelist[lane].has_err) {
void *zero_page = page_address(ZERO_PAGE(0));
u32 lba = arena->freelist[lane].block;
u64 nsoff = to_namespace_offset(arena, lba);
unsigned long len = arena->sector_size;
mutex_lock(&arena->err_lock);
while (len) {
unsigned long chunk = min(len, PAGE_SIZE);
ret = arena_write_bytes(arena, nsoff, zero_page,
chunk, 0);
if (ret)
break;
len -= chunk;
nsoff += chunk;
if (len == 0)
arena->freelist[lane].has_err = 0;
}
mutex_unlock(&arena->err_lock);
}
return ret;
}
static int btt_freelist_init(struct arena_info *arena)
{
int old, new, ret;
u32 i, map_entry;
struct log_entry log_new, log_old;
arena->freelist = kcalloc(arena->nfree, sizeof(struct free_entry),
GFP_KERNEL);
if (!arena->freelist)
return -ENOMEM;
for (i = 0; i < arena->nfree; i++) {
old = btt_log_read(arena, i, &log_old, LOG_OLD_ENT);
if (old < 0)
return old;
new = btt_log_read(arena, i, &log_new, LOG_NEW_ENT);
if (new < 0)
return new;
/* sub points to the next one to be overwritten */
arena->freelist[i].sub = 1 - new;
arena->freelist[i].seq = nd_inc_seq(le32_to_cpu(log_new.seq));
arena->freelist[i].block = le32_to_cpu(log_new.old_map);
/*
* FIXME: if error clearing fails during init, we want to make
* the BTT read-only
*/
if (ent_e_flag(log_new.old_map)) {
ret = arena_clear_freelist_error(arena, i);
if (ret)
dev_err_ratelimited(to_dev(arena),
"Unable to clear known errors\n");
}
/* This implies a newly created or untouched flog entry */
if (log_new.old_map == log_new.new_map)
continue;
/* Check if map recovery is needed */
ret = btt_map_read(arena, le32_to_cpu(log_new.lba), &map_entry,
NULL, NULL, 0);
if (ret)
return ret;
if ((le32_to_cpu(log_new.new_map) != map_entry) &&
(le32_to_cpu(log_new.old_map) == map_entry)) {
/*
* Last transaction wrote the flog, but wasn't able
* to complete the map write. So fix up the map.
*/
ret = btt_map_write(arena, le32_to_cpu(log_new.lba),
le32_to_cpu(log_new.new_map), 0, 0, 0);
if (ret)
return ret;
}
}
return 0;
}
static bool ent_is_padding(struct log_entry *ent)
{
return (ent->lba == 0) && (ent->old_map == 0) && (ent->new_map == 0)
&& (ent->seq == 0);
}
/*
* Detecting valid log indices: We read a log group (see the comments in btt.h
* for a description of a 'log_group' and its 'slots'), and iterate over its
* four slots. We expect that a padding slot will be all-zeroes, and use this
* to detect a padding slot vs. an actual entry.
*
* If a log_group is in the initial state, i.e. hasn't been used since the
* creation of this BTT layout, it will have three of the four slots with
* zeroes. We skip over these log_groups for the detection of log_index. If
* all log_groups are in the initial state (i.e. the BTT has never been
* written to), it is safe to assume the 'new format' of log entries in slots
* (0, 1).
*/
static int log_set_indices(struct arena_info *arena)
{
bool idx_set = false, initial_state = true;
int ret, log_index[2] = {-1, -1};
u32 i, j, next_idx = 0;
struct log_group log;
u32 pad_count = 0;
for (i = 0; i < arena->nfree; i++) {
ret = btt_log_group_read(arena, i, &log);
if (ret < 0)
return ret;
for (j = 0; j < 4; j++) {
if (!idx_set) {
if (ent_is_padding(&log.ent[j])) {
pad_count++;
continue;
} else {
/* Skip if index has been recorded */
if ((next_idx == 1) &&
(j == log_index[0]))
continue;
/* valid entry, record index */
log_index[next_idx] = j;
next_idx++;
}
if (next_idx == 2) {
/* two valid entries found */
idx_set = true;
} else if (next_idx > 2) {
/* too many valid indices */
return -ENXIO;
}
} else {
/*
* once the indices have been set, just verify
* that all subsequent log groups are either in
* their initial state or follow the same
* indices.
*/
if (j == log_index[0]) {
/* entry must be 'valid' */
if (ent_is_padding(&log.ent[j]))
return -ENXIO;
} else if (j == log_index[1]) {
;
/*
* log_index[1] can be padding if the
* lane never got used and it is still
* in the initial state (three 'padding'
* entries)
*/
} else {
/* entry must be invalid (padding) */
if (!ent_is_padding(&log.ent[j]))
return -ENXIO;
}
}
}
/*
* If any of the log_groups have more than one valid,
* non-padding entry, then the we are no longer in the
* initial_state
*/
if (pad_count < 3)
initial_state = false;
pad_count = 0;
}
if (!initial_state && !idx_set)
return -ENXIO;
/*
* If all the entries in the log were in the initial state,
* assume new padding scheme
*/
if (initial_state)
log_index[1] = 1;
/*
* Only allow the known permutations of log/padding indices,
* i.e. (0, 1), and (0, 2)
*/
if ((log_index[0] == 0) && ((log_index[1] == 1) || (log_index[1] == 2)))
; /* known index possibilities */
else {
dev_err(to_dev(arena), "Found an unknown padding scheme\n");
return -ENXIO;
}
arena->log_index[0] = log_index[0];
arena->log_index[1] = log_index[1];
dev_dbg(to_dev(arena), "log_index_0 = %d\n", log_index[0]);
dev_dbg(to_dev(arena), "log_index_1 = %d\n", log_index[1]);
return 0;
}
static int btt_rtt_init(struct arena_info *arena)
{
arena->rtt = kcalloc(arena->nfree, sizeof(u32), GFP_KERNEL);
if (arena->rtt == NULL)
return -ENOMEM;
return 0;
}
static int btt_maplocks_init(struct arena_info *arena)
{
u32 i;
arena->map_locks = kcalloc(arena->nfree, sizeof(struct aligned_lock),
GFP_KERNEL);
if (!arena->map_locks)
return -ENOMEM;
for (i = 0; i < arena->nfree; i++)
spin_lock_init(&arena->map_locks[i].lock);
return 0;
}
static struct arena_info *alloc_arena(struct btt *btt, size_t size,
size_t start, size_t arena_off)
{
struct arena_info *arena;
u64 logsize, mapsize, datasize;
u64 available = size;
arena = kzalloc(sizeof(struct arena_info), GFP_KERNEL);
if (!arena)
return NULL;
arena->nd_btt = btt->nd_btt;
arena->sector_size = btt->sector_size;
if (!size)
return arena;
arena->size = size;
arena->external_lba_start = start;
arena->external_lbasize = btt->lbasize;
arena->internal_lbasize = roundup(arena->external_lbasize,
INT_LBASIZE_ALIGNMENT);
arena->nfree = BTT_DEFAULT_NFREE;
arena->version_major = btt->nd_btt->version_major;
arena->version_minor = btt->nd_btt->version_minor;
if (available % BTT_PG_SIZE)
available -= (available % BTT_PG_SIZE);
/* Two pages are reserved for the super block and its copy */
available -= 2 * BTT_PG_SIZE;
/* The log takes a fixed amount of space based on nfree */
logsize = roundup(arena->nfree * LOG_GRP_SIZE, BTT_PG_SIZE);
available -= logsize;
/* Calculate optimal split between map and data area */
arena->internal_nlba = div_u64(available - BTT_PG_SIZE,
arena->internal_lbasize + MAP_ENT_SIZE);
arena->external_nlba = arena->internal_nlba - arena->nfree;
mapsize = roundup((arena->external_nlba * MAP_ENT_SIZE), BTT_PG_SIZE);
datasize = available - mapsize;
/* 'Absolute' values, relative to start of storage space */
arena->infooff = arena_off;
arena->dataoff = arena->infooff + BTT_PG_SIZE;
arena->mapoff = arena->dataoff + datasize;
arena->logoff = arena->mapoff + mapsize;
arena->info2off = arena->logoff + logsize;
/* Default log indices are (0,1) */
arena->log_index[0] = 0;
arena->log_index[1] = 1;
return arena;
}
static void free_arenas(struct btt *btt)
{
struct arena_info *arena, *next;
list_for_each_entry_safe(arena, next, &btt->arena_list, list) {
list_del(&arena->list);
kfree(arena->rtt);
kfree(arena->map_locks);
kfree(arena->freelist);
debugfs_remove_recursive(arena->debugfs_dir);
kfree(arena);
}
}
/*
* This function reads an existing valid btt superblock and
* populates the corresponding arena_info struct
*/
static void parse_arena_meta(struct arena_info *arena, struct btt_sb *super,
u64 arena_off)
{
arena->internal_nlba = le32_to_cpu(super->internal_nlba);
arena->internal_lbasize = le32_to_cpu(super->internal_lbasize);
arena->external_nlba = le32_to_cpu(super->external_nlba);
arena->external_lbasize = le32_to_cpu(super->external_lbasize);
arena->nfree = le32_to_cpu(super->nfree);
arena->version_major = le16_to_cpu(super->version_major);
arena->version_minor = le16_to_cpu(super->version_minor);
arena->nextoff = (super->nextoff == 0) ? 0 : (arena_off +
le64_to_cpu(super->nextoff));
arena->infooff = arena_off;
arena->dataoff = arena_off + le64_to_cpu(super->dataoff);
arena->mapoff = arena_off + le64_to_cpu(super->mapoff);
arena->logoff = arena_off + le64_to_cpu(super->logoff);
arena->info2off = arena_off + le64_to_cpu(super->info2off);
arena->size = (le64_to_cpu(super->nextoff) > 0)
? (le64_to_cpu(super->nextoff))
: (arena->info2off - arena->infooff + BTT_PG_SIZE);
arena->flags = le32_to_cpu(super->flags);
}
static int discover_arenas(struct btt *btt)
{
int ret = 0;
struct arena_info *arena;
struct btt_sb *super;
size_t remaining = btt->rawsize;
u64 cur_nlba = 0;
size_t cur_off = 0;
int num_arenas = 0;
super = kzalloc(sizeof(*super), GFP_KERNEL);
if (!super)
return -ENOMEM;
while (remaining) {
/* Alloc memory for arena */
arena = alloc_arena(btt, 0, 0, 0);
if (!arena) {
ret = -ENOMEM;
goto out_super;
}
arena->infooff = cur_off;
ret = btt_info_read(arena, super);
if (ret)
goto out;
if (!nd_btt_arena_is_valid(btt->nd_btt, super)) {
if (remaining == btt->rawsize) {
btt->init_state = INIT_NOTFOUND;
dev_info(to_dev(arena), "No existing arenas\n");
goto out;
} else {
dev_err(to_dev(arena),
"Found corrupted metadata!\n");
ret = -ENODEV;
goto out;
}
}
arena->external_lba_start = cur_nlba;
parse_arena_meta(arena, super, cur_off);
ret = log_set_indices(arena);
if (ret) {
dev_err(to_dev(arena),
"Unable to deduce log/padding indices\n");
goto out;
}
mutex_init(&arena->err_lock);
ret = btt_freelist_init(arena);
if (ret)
goto out;
ret = btt_rtt_init(arena);
if (ret)
goto out;
ret = btt_maplocks_init(arena);
if (ret)
goto out;
list_add_tail(&arena->list, &btt->arena_list);
remaining -= arena->size;
cur_off += arena->size;
cur_nlba += arena->external_nlba;
num_arenas++;
if (arena->nextoff == 0)
break;
}
btt->num_arenas = num_arenas;
btt->nlba = cur_nlba;
btt->init_state = INIT_READY;
kfree(super);
return ret;
out:
kfree(arena);
free_arenas(btt);
out_super:
kfree(super);
return ret;
}
static int create_arenas(struct btt *btt)
{
size_t remaining = btt->rawsize;
size_t cur_off = 0;
while (remaining) {
struct arena_info *arena;
size_t arena_size = min_t(u64, ARENA_MAX_SIZE, remaining);
remaining -= arena_size;
if (arena_size < ARENA_MIN_SIZE)
break;
arena = alloc_arena(btt, arena_size, btt->nlba, cur_off);
if (!arena) {
free_arenas(btt);
return -ENOMEM;
}
btt->nlba += arena->external_nlba;
if (remaining >= ARENA_MIN_SIZE)
arena->nextoff = arena->size;
else
arena->nextoff = 0;
cur_off += arena_size;
list_add_tail(&arena->list, &btt->arena_list);
}
return 0;
}
/*
* This function completes arena initialization by writing
* all the metadata.
* It is only called for an uninitialized arena when a write
* to that arena occurs for the first time.
*/
static int btt_arena_write_layout(struct arena_info *arena)
{
int ret;
u64 sum;
struct btt_sb *super;
struct nd_btt *nd_btt = arena->nd_btt;
const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
ret = btt_map_init(arena);
if (ret)
return ret;
ret = btt_log_init(arena);
if (ret)
return ret;
super = kzalloc(sizeof(struct btt_sb), GFP_NOIO);
if (!super)
return -ENOMEM;
strncpy(super->signature, BTT_SIG, BTT_SIG_LEN);
memcpy(super->uuid, nd_btt->uuid, 16);
memcpy(super->parent_uuid, parent_uuid, 16);
super->flags = cpu_to_le32(arena->flags);
super->version_major = cpu_to_le16(arena->version_major);
super->version_minor = cpu_to_le16(arena->version_minor);
super->external_lbasize = cpu_to_le32(arena->external_lbasize);
super->external_nlba = cpu_to_le32(arena->external_nlba);
super->internal_lbasize = cpu_to_le32(arena->internal_lbasize);
super->internal_nlba = cpu_to_le32(arena->internal_nlba);
super->nfree = cpu_to_le32(arena->nfree);
super->infosize = cpu_to_le32(sizeof(struct btt_sb));
super->nextoff = cpu_to_le64(arena->nextoff);
/*
* Subtract arena->infooff (arena start) so numbers are relative
* to 'this' arena
*/
super->dataoff = cpu_to_le64(arena->dataoff - arena->infooff);
super->mapoff = cpu_to_le64(arena->mapoff - arena->infooff);
super->logoff = cpu_to_le64(arena->logoff - arena->infooff);
super->info2off = cpu_to_le64(arena->info2off - arena->infooff);
super->flags = 0;
sum = nd_sb_checksum((struct nd_gen_sb *) super);
super->checksum = cpu_to_le64(sum);
ret = btt_info_write(arena, super);
kfree(super);
return ret;
}
/*
* This function completes the initialization for the BTT namespace
* such that it is ready to accept IOs
*/
static int btt_meta_init(struct btt *btt)
{
int ret = 0;
struct arena_info *arena;
mutex_lock(&btt->init_lock);
list_for_each_entry(arena, &btt->arena_list, list) {
ret = btt_arena_write_layout(arena);
if (ret)
goto unlock;
ret = btt_freelist_init(arena);
if (ret)
goto unlock;
ret = btt_rtt_init(arena);
if (ret)
goto unlock;
ret = btt_maplocks_init(arena);
if (ret)
goto unlock;
}
btt->init_state = INIT_READY;
unlock:
mutex_unlock(&btt->init_lock);
return ret;
}
static u32 btt_meta_size(struct btt *btt)
{
return btt->lbasize - btt->sector_size;
}
/*
* This function calculates the arena in which the given LBA lies
* by doing a linear walk. This is acceptable since we expect only
* a few arenas. If we have backing devices that get much larger,
* we can construct a balanced binary tree of arenas at init time
* so that this range search becomes faster.
*/
static int lba_to_arena(struct btt *btt, sector_t sector, __u32 *premap,
struct arena_info **arena)
{
struct arena_info *arena_list;
__u64 lba = div_u64(sector << SECTOR_SHIFT, btt->sector_size);
list_for_each_entry(arena_list, &btt->arena_list, list) {
if (lba < arena_list->external_nlba) {
*arena = arena_list;
*premap = lba;
return 0;
}
lba -= arena_list->external_nlba;
}
return -EIO;
}
/*
* The following (lock_map, unlock_map) are mostly just to improve
* readability, since they index into an array of locks
*/
static void lock_map(struct arena_info *arena, u32 premap)
__acquires(&arena->map_locks[idx].lock)
{
u32 idx = (premap * MAP_ENT_SIZE / L1_CACHE_BYTES) % arena->nfree;
spin_lock(&arena->map_locks[idx].lock);
}
static void unlock_map(struct arena_info *arena, u32 premap)
__releases(&arena->map_locks[idx].lock)
{
u32 idx = (premap * MAP_ENT_SIZE / L1_CACHE_BYTES) % arena->nfree;
spin_unlock(&arena->map_locks[idx].lock);
}
static int btt_data_read(struct arena_info *arena, struct page *page,
unsigned int off, u32 lba, u32 len)
{
int ret;
u64 nsoff = to_namespace_offset(arena, lba);
void *mem = kmap_atomic(page);
ret = arena_read_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);
kunmap_atomic(mem);
return ret;
}
static int btt_data_write(struct arena_info *arena, u32 lba,
struct page *page, unsigned int off, u32 len)
{
int ret;
u64 nsoff = to_namespace_offset(arena, lba);
void *mem = kmap_atomic(page);
ret = arena_write_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);
kunmap_atomic(mem);
return ret;
}
static void zero_fill_data(struct page *page, unsigned int off, u32 len)
{
void *mem = kmap_atomic(page);
memset(mem + off, 0, len);
kunmap_atomic(mem);
}
#ifdef CONFIG_BLK_DEV_INTEGRITY
static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip,
struct arena_info *arena, u32 postmap, int rw)
{
unsigned int len = btt_meta_size(btt);
u64 meta_nsoff;
int ret = 0;
if (bip == NULL)
return 0;
meta_nsoff = to_namespace_offset(arena, postmap) + btt->sector_size;
while (len) {
unsigned int cur_len;
struct bio_vec bv;
void *mem;
bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
/*
* The 'bv' obtained from bvec_iter_bvec has its .bv_len and
* .bv_offset already adjusted for iter->bi_bvec_done, and we
* can use those directly
*/
cur_len = min(len, bv.bv_len);
mem = kmap_atomic(bv.bv_page);
if (rw)
ret = arena_write_bytes(arena, meta_nsoff,
mem + bv.bv_offset, cur_len,
NVDIMM_IO_ATOMIC);
else
ret = arena_read_bytes(arena, meta_nsoff,
mem + bv.bv_offset, cur_len,
NVDIMM_IO_ATOMIC);
kunmap_atomic(mem);
if (ret)
return ret;
len -= cur_len;
meta_nsoff += cur_len;
if (!bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len))
return -EIO;
}
return ret;
}
#else /* CONFIG_BLK_DEV_INTEGRITY */
static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip,
struct arena_info *arena, u32 postmap, int rw)
{
return 0;
}
#endif
static int btt_read_pg(struct btt *btt, struct bio_integrity_payload *bip,
struct page *page, unsigned int off, sector_t sector,
unsigned int len)
{
int ret = 0;
int t_flag, e_flag;
struct arena_info *arena = NULL;
u32 lane = 0, premap, postmap;
while (len) {
u32 cur_len;
lane = nd_region_acquire_lane(btt->nd_region);
ret = lba_to_arena(btt, sector, &premap, &arena);
if (ret)
goto out_lane;
cur_len = min(btt->sector_size, len);
ret = btt_map_read(arena, premap, &postmap, &t_flag, &e_flag,
NVDIMM_IO_ATOMIC);
if (ret)
goto out_lane;
/*
* We loop to make sure that the post map LBA didn't change
* from under us between writing the RTT and doing the actual
* read.
*/
while (1) {
u32 new_map;
int new_t, new_e;
if (t_flag) {
zero_fill_data(page, off, cur_len);
goto out_lane;
}
if (e_flag) {
ret = -EIO;
goto out_lane;
}
arena->rtt[lane] = RTT_VALID | postmap;
/*
* Barrier to make sure this write is not reordered
* to do the verification map_read before the RTT store
*/
barrier();
ret = btt_map_read(arena, premap, &new_map, &new_t,
&new_e, NVDIMM_IO_ATOMIC);
if (ret)
goto out_rtt;
if ((postmap == new_map) && (t_flag == new_t) &&
(e_flag == new_e))
break;
postmap = new_map;
t_flag = new_t;
e_flag = new_e;
}
ret = btt_data_read(arena, page, off, postmap, cur_len);
if (ret) {
int rc;
/* Media error - set the e_flag */
rc = btt_map_write(arena, premap, postmap, 0, 1,
NVDIMM_IO_ATOMIC);
goto out_rtt;
}
if (bip) {
ret = btt_rw_integrity(btt, bip, arena, postmap, READ);
if (ret)
goto out_rtt;
}
arena->rtt[lane] = RTT_INVALID;
nd_region_release_lane(btt->nd_region, lane);
len -= cur_len;
off += cur_len;
sector += btt->sector_size >> SECTOR_SHIFT;
}
return 0;
out_rtt:
arena->rtt[lane] = RTT_INVALID;
out_lane:
nd_region_release_lane(btt->nd_region, lane);
return ret;
}
/*
* Normally, arena_{read,write}_bytes will take care of the initial offset
* adjustment, but in the case of btt_is_badblock, where we query is_bad_pmem,
* we need the final, raw namespace offset here
*/
static bool btt_is_badblock(struct btt *btt, struct arena_info *arena,
u32 postmap)
{
u64 nsoff = adjust_initial_offset(arena->nd_btt,
to_namespace_offset(arena, postmap));
sector_t phys_sector = nsoff >> 9;
return is_bad_pmem(btt->phys_bb, phys_sector, arena->internal_lbasize);
}
static int btt_write_pg(struct btt *btt, struct bio_integrity_payload *bip,
sector_t sector, struct page *page, unsigned int off,
unsigned int len)
{
int ret = 0;
struct arena_info *arena = NULL;
u32 premap = 0, old_postmap, new_postmap, lane = 0, i;
struct log_entry log;
int sub;
while (len) {
u32 cur_len;
int e_flag;
retry:
lane = nd_region_acquire_lane(btt->nd_region);
ret = lba_to_arena(btt, sector, &premap, &arena);
if (ret)
goto out_lane;
cur_len = min(btt->sector_size, len);
if ((arena->flags & IB_FLAG_ERROR_MASK) != 0) {
ret = -EIO;
goto out_lane;
}
if (btt_is_badblock(btt, arena, arena->freelist[lane].block))
arena->freelist[lane].has_err = 1;
if (mutex_is_locked(&arena->err_lock)
|| arena->freelist[lane].has_err) {
nd_region_release_lane(btt->nd_region, lane);
ret = arena_clear_freelist_error(arena, lane);
if (ret)
return ret;
/* OK to acquire a different lane/free block */
goto retry;
}
new_postmap = arena->freelist[lane].block;
/* Wait if the new block is being read from */
for (i = 0; i < arena->nfree; i++)
while (arena->rtt[i] == (RTT_VALID | new_postmap))
cpu_relax();
if (new_postmap >= arena->internal_nlba) {
ret = -EIO;
goto out_lane;
}
ret = btt_data_write(arena, new_postmap, page, off, cur_len);
if (ret)
goto out_lane;
if (bip) {
ret = btt_rw_integrity(btt, bip, arena, new_postmap,
WRITE);
if (ret)
goto out_lane;
}
lock_map(arena, premap);
ret = btt_map_read(arena, premap, &old_postmap, NULL, &e_flag,
NVDIMM_IO_ATOMIC);
if (ret)
goto out_map;
if (old_postmap >= arena->internal_nlba) {
ret = -EIO;
goto out_map;
}
if (e_flag)
set_e_flag(old_postmap);
log.lba = cpu_to_le32(premap);
log.old_map = cpu_to_le32(old_postmap);
log.new_map = cpu_to_le32(new_postmap);
log.seq = cpu_to_le32(arena->freelist[lane].seq);
sub = arena->freelist[lane].sub;
ret = btt_flog_write(arena, lane, sub, &log);
if (ret)
goto out_map;
ret = btt_map_write(arena, premap, new_postmap, 0, 0,
NVDIMM_IO_ATOMIC);
if (ret)
goto out_map;
unlock_map(arena, premap);
nd_region_release_lane(btt->nd_region, lane);
if (e_flag) {
ret = arena_clear_freelist_error(arena, lane);
if (ret)
return ret;
}
len -= cur_len;
off += cur_len;
sector += btt->sector_size >> SECTOR_SHIFT;
}
return 0;
out_map:
unlock_map(arena, premap);
out_lane:
nd_region_release_lane(btt->nd_region, lane);
return ret;
}
static int btt_do_bvec(struct btt *btt, struct bio_integrity_payload *bip,
struct page *page, unsigned int len, unsigned int off,
bool is_write, sector_t sector)
{
int ret;
if (!is_write) {
ret = btt_read_pg(btt, bip, page, off, sector, len);
flush_dcache_page(page);
} else {
flush_dcache_page(page);
ret = btt_write_pg(btt, bip, sector, page, off, len);
}
return ret;
}
static blk_qc_t btt_make_request(struct request_queue *q, struct bio *bio)
{
struct bio_integrity_payload *bip = bio_integrity(bio);
struct btt *btt = q->queuedata;
struct bvec_iter iter;
unsigned long start;
struct bio_vec bvec;
int err = 0;
bool do_acct;
if (!bio_integrity_prep(bio))
return BLK_QC_T_NONE;
do_acct = nd_iostat_start(bio, &start);
bio_for_each_segment(bvec, bio, iter) {
unsigned int len = bvec.bv_len;
if (len > PAGE_SIZE || len < btt->sector_size ||
len % btt->sector_size) {
dev_err_ratelimited(&btt->nd_btt->dev,
"unaligned bio segment (len: %d)\n", len);
bio->bi_status = BLK_STS_IOERR;
break;
}
err = btt_do_bvec(btt, bip, bvec.bv_page, len, bvec.bv_offset,
op_is_write(bio_op(bio)), iter.bi_sector);
if (err) {
dev_err(&btt->nd_btt->dev,
"io error in %s sector %lld, len %d,\n",
(op_is_write(bio_op(bio))) ? "WRITE" :
"READ",
(unsigned long long) iter.bi_sector, len);
bio->bi_status = errno_to_blk_status(err);
break;
}
}
if (do_acct)
nd_iostat_end(bio, start);
bio_endio(bio);
return BLK_QC_T_NONE;
}
static int btt_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, bool is_write)
{
struct btt *btt = bdev->bd_disk->private_data;
int rc;
unsigned int len;
len = hpage_nr_pages(page) * PAGE_SIZE;
rc = btt_do_bvec(btt, NULL, page, len, 0, is_write, sector);
if (rc == 0)
page_endio(page, is_write, 0);
return rc;
}
static int btt_getgeo(struct block_device *bd, struct hd_geometry *geo)
{
/* some standard values */
geo->heads = 1 << 6;
geo->sectors = 1 << 5;
geo->cylinders = get_capacity(bd->bd_disk) >> 11;
return 0;
}
static const struct block_device_operations btt_fops = {
.owner = THIS_MODULE,
.rw_page = btt_rw_page,
.getgeo = btt_getgeo,
.revalidate_disk = nvdimm_revalidate_disk,
};
static int btt_blk_init(struct btt *btt)
{
struct nd_btt *nd_btt = btt->nd_btt;
struct nd_namespace_common *ndns = nd_btt->ndns;
/* create a new disk and request queue for btt */
btt->btt_queue = blk_alloc_queue(GFP_KERNEL);
if (!btt->btt_queue)
return -ENOMEM;
btt->btt_disk = alloc_disk(0);
if (!btt->btt_disk) {
blk_cleanup_queue(btt->btt_queue);
return -ENOMEM;
}
nvdimm_namespace_disk_name(ndns, btt->btt_disk->disk_name);
btt->btt_disk->first_minor = 0;
btt->btt_disk->fops = &btt_fops;
btt->btt_disk->private_data = btt;
btt->btt_disk->queue = btt->btt_queue;
btt->btt_disk->flags = GENHD_FL_EXT_DEVT;
btt->btt_disk->queue->backing_dev_info->capabilities |=
BDI_CAP_SYNCHRONOUS_IO;
blk_queue_make_request(btt->btt_queue, btt_make_request);
blk_queue_logical_block_size(btt->btt_queue, btt->sector_size);
blk_queue_max_hw_sectors(btt->btt_queue, UINT_MAX);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, btt->btt_queue);
btt->btt_queue->queuedata = btt;
set_capacity(btt->btt_disk, 0);
device_add_disk(&btt->nd_btt->dev, btt->btt_disk);
if (btt_meta_size(btt)) {
int rc = nd_integrity_init(btt->btt_disk, btt_meta_size(btt));
if (rc) {
del_gendisk(btt->btt_disk);
put_disk(btt->btt_disk);
blk_cleanup_queue(btt->btt_queue);
return rc;
}
}
set_capacity(btt->btt_disk, btt->nlba * btt->sector_size >> 9);
btt->nd_btt->size = btt->nlba * (u64)btt->sector_size;
revalidate_disk(btt->btt_disk);
return 0;
}
static void btt_blk_cleanup(struct btt *btt)
{
del_gendisk(btt->btt_disk);
put_disk(btt->btt_disk);
blk_cleanup_queue(btt->btt_queue);
}
/**
* btt_init - initialize a block translation table for the given device
* @nd_btt: device with BTT geometry and backing device info
* @rawsize: raw size in bytes of the backing device
* @lbasize: lba size of the backing device
* @uuid: A uuid for the backing device - this is stored on media
* @maxlane: maximum number of parallel requests the device can handle
*
* Initialize a Block Translation Table on a backing device to provide
* single sector power fail atomicity.
*
* Context:
* Might sleep.
*
* Returns:
* Pointer to a new struct btt on success, NULL on failure.
*/
static struct btt *btt_init(struct nd_btt *nd_btt, unsigned long long rawsize,
u32 lbasize, u8 *uuid, struct nd_region *nd_region)
{
int ret;
struct btt *btt;
struct nd_namespace_io *nsio;
struct device *dev = &nd_btt->dev;
btt = devm_kzalloc(dev, sizeof(struct btt), GFP_KERNEL);
if (!btt)
return NULL;
btt->nd_btt = nd_btt;
btt->rawsize = rawsize;
btt->lbasize = lbasize;
btt->sector_size = ((lbasize >= 4096) ? 4096 : 512);
INIT_LIST_HEAD(&btt->arena_list);
mutex_init(&btt->init_lock);
btt->nd_region = nd_region;
nsio = to_nd_namespace_io(&nd_btt->ndns->dev);
btt->phys_bb = &nsio->bb;
ret = discover_arenas(btt);
if (ret) {
dev_err(dev, "init: error in arena_discover: %d\n", ret);
return NULL;
}
if (btt->init_state != INIT_READY && nd_region->ro) {
dev_warn(dev, "%s is read-only, unable to init btt metadata\n",
dev_name(&nd_region->dev));
return NULL;
} else if (btt->init_state != INIT_READY) {
btt->num_arenas = (rawsize / ARENA_MAX_SIZE) +
((rawsize % ARENA_MAX_SIZE) ? 1 : 0);
dev_dbg(dev, "init: %d arenas for %llu rawsize\n",
btt->num_arenas, rawsize);
ret = create_arenas(btt);
if (ret) {
dev_info(dev, "init: create_arenas: %d\n", ret);
return NULL;
}
ret = btt_meta_init(btt);
if (ret) {
dev_err(dev, "init: error in meta_init: %d\n", ret);
return NULL;
}
}
ret = btt_blk_init(btt);
if (ret) {
dev_err(dev, "init: error in blk_init: %d\n", ret);
return NULL;
}
btt_debugfs_init(btt);
return btt;
}
/**
* btt_fini - de-initialize a BTT
* @btt: the BTT handle that was generated by btt_init
*
* De-initialize a Block Translation Table on device removal
*
* Context:
* Might sleep.
*/
static void btt_fini(struct btt *btt)
{
if (btt) {
btt_blk_cleanup(btt);
free_arenas(btt);
debugfs_remove_recursive(btt->debugfs_dir);
}
}
int nvdimm_namespace_attach_btt(struct nd_namespace_common *ndns)
{
struct nd_btt *nd_btt = to_nd_btt(ndns->claim);
struct nd_region *nd_region;
struct btt_sb *btt_sb;
struct btt *btt;
size_t rawsize;
if (!nd_btt->uuid || !nd_btt->ndns || !nd_btt->lbasize) {
dev_dbg(&nd_btt->dev, "incomplete btt configuration\n");
return -ENODEV;
}
btt_sb = devm_kzalloc(&nd_btt->dev, sizeof(*btt_sb), GFP_KERNEL);
if (!btt_sb)
return -ENOMEM;
/*
* If this returns < 0, that is ok as it just means there wasn't
* an existing BTT, and we're creating a new one. We still need to
* call this as we need the version dependent fields in nd_btt to be
* set correctly based on the holder class
*/
nd_btt_version(nd_btt, ndns, btt_sb);
rawsize = nvdimm_namespace_capacity(ndns) - nd_btt->initial_offset;
if (rawsize < ARENA_MIN_SIZE) {
dev_dbg(&nd_btt->dev, "%s must be at least %ld bytes\n",
dev_name(&ndns->dev),
ARENA_MIN_SIZE + nd_btt->initial_offset);
return -ENXIO;
}
nd_region = to_nd_region(nd_btt->dev.parent);
btt = btt_init(nd_btt, rawsize, nd_btt->lbasize, nd_btt->uuid,
nd_region);
if (!btt)
return -ENOMEM;
nd_btt->btt = btt;
return 0;
}
EXPORT_SYMBOL(nvdimm_namespace_attach_btt);
int nvdimm_namespace_detach_btt(struct nd_btt *nd_btt)
{
struct btt *btt = nd_btt->btt;
btt_fini(btt);
nd_btt->btt = NULL;
return 0;
}
EXPORT_SYMBOL(nvdimm_namespace_detach_btt);
static int __init nd_btt_init(void)
{
int rc = 0;
debugfs_root = debugfs_create_dir("btt", NULL);
if (IS_ERR_OR_NULL(debugfs_root))
rc = -ENXIO;
return rc;
}
static void __exit nd_btt_exit(void)
{
debugfs_remove_recursive(debugfs_root);
}
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_BTT);
MODULE_AUTHOR("Vishal Verma <vishal.l.verma@linux.intel.com>");
MODULE_LICENSE("GPL v2");
module_init(nd_btt_init);
module_exit(nd_btt_exit);