diff options
Diffstat (limited to 'drivers/nvdimm/btt.c')
| -rw-r--r-- | drivers/nvdimm/btt.c | 201 |
1 files changed, 167 insertions, 34 deletions
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c index e949e3302af4..c586bcdb5190 100644 --- a/drivers/nvdimm/btt.c +++ b/drivers/nvdimm/btt.c @@ -211,12 +211,12 @@ static int btt_map_read(struct arena_info *arena, u32 lba, u32 *mapping, return ret; } -static int btt_log_read_pair(struct arena_info *arena, u32 lane, - struct log_entry *ent) +static int btt_log_group_read(struct arena_info *arena, u32 lane, + struct log_group *log) { return arena_read_bytes(arena, - arena->logoff + (2 * lane * LOG_ENT_SIZE), ent, - 2 * LOG_ENT_SIZE, 0); + arena->logoff + (lane * LOG_GRP_SIZE), log, + LOG_GRP_SIZE, 0); } static struct dentry *debugfs_root; @@ -256,6 +256,8 @@ static void arena_debugfs_init(struct arena_info *a, struct dentry *parent, 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) @@ -274,6 +276,11 @@ static void btt_debugfs_init(struct btt *btt) } } +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. @@ -283,8 +290,10 @@ static void btt_debugfs_init(struct btt *btt) * * TODO The logic feels a bit kludge-y. make it better.. */ -static int btt_log_get_old(struct log_entry *ent) +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; /* @@ -292,23 +301,23 @@ static int btt_log_get_old(struct log_entry *ent) * the next time, the following logic works out to put this * (next) entry into [1] */ - if (ent[0].seq == 0) { - ent[0].seq = cpu_to_le32(1); + if (log_seq(log, idx0) == 0) { + log->ent[idx0].seq = cpu_to_le32(1); return 0; } - if (ent[0].seq == ent[1].seq) + if (log_seq(log, idx0) == log_seq(log, idx1)) return -EINVAL; - if (le32_to_cpu(ent[0].seq) + le32_to_cpu(ent[1].seq) > 5) + if (log_seq(log, idx0) + log_seq(log, idx1) > 5) return -EINVAL; - if (le32_to_cpu(ent[0].seq) < le32_to_cpu(ent[1].seq)) { - if (le32_to_cpu(ent[1].seq) - le32_to_cpu(ent[0].seq) == 1) + 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 (le32_to_cpu(ent[0].seq) - le32_to_cpu(ent[1].seq) == 1) + if ((log_seq(log, idx0) - log_seq(log, idx1)) == 1) old = 1; else old = 0; @@ -328,17 +337,18 @@ static int btt_log_read(struct arena_info *arena, u32 lane, { int ret; int old_ent, ret_ent; - struct log_entry log[2]; + struct log_group log; - ret = btt_log_read_pair(arena, lane, log); + ret = btt_log_group_read(arena, lane, &log); if (ret) return -EIO; - old_ent = btt_log_get_old(log); + 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[0].seq, log[1].seq); + old_ent, lane, log.ent[arena->log_index[0]].seq, + log.ent[arena->log_index[1]].seq); /* TODO set error state? */ return -EIO; } @@ -346,7 +356,7 @@ static int btt_log_read(struct arena_info *arena, u32 lane, ret_ent = (old_flag ? old_ent : (1 - old_ent)); if (ent != NULL) - memcpy(ent, &log[ret_ent], LOG_ENT_SIZE); + memcpy(ent, &log.ent[arena->log_index[ret_ent]], LOG_ENT_SIZE); return ret_ent; } @@ -360,17 +370,13 @@ static int __btt_log_write(struct arena_info *arena, u32 lane, u32 sub, struct log_entry *ent, unsigned long flags) { int ret; - /* - * Ignore the padding in log_entry for calculating log_half. - * The entry is 'committed' when we write the sequence number, - * and we want to ensure that that is the last thing written. - * We don't bother writing the padding as that would be extra - * media wear and write amplification - */ - unsigned int log_half = (LOG_ENT_SIZE - 2 * sizeof(u64)) / 2; - u64 ns_off = arena->logoff + (((2 * lane) + sub) * LOG_ENT_SIZE); + 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) @@ -453,7 +459,7 @@ 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 log; + struct log_entry ent; void *zerobuf; int ret; u32 i; @@ -485,11 +491,11 @@ static int btt_log_init(struct arena_info *arena) } for (i = 0; i < arena->nfree; i++) { - log.lba = cpu_to_le32(i); - log.old_map = cpu_to_le32(arena->external_nlba + i); - log.new_map = cpu_to_le32(arena->external_nlba + i); - log.seq = cpu_to_le32(LOG_SEQ_INIT); - ret = __btt_log_write(arena, i, 0, &log, 0); + 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; } @@ -594,6 +600,123 @@ static int btt_freelist_init(struct arena_info *arena) 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); @@ -650,8 +773,7 @@ static struct arena_info *alloc_arena(struct btt *btt, size_t size, available -= 2 * BTT_PG_SIZE; /* The log takes a fixed amount of space based on nfree */ - logsize = roundup(2 * arena->nfree * sizeof(struct log_entry), - BTT_PG_SIZE); + logsize = roundup(arena->nfree * LOG_GRP_SIZE, BTT_PG_SIZE); available -= logsize; /* Calculate optimal split between map and data area */ @@ -668,6 +790,10 @@ static struct arena_info *alloc_arena(struct btt *btt, size_t 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; } @@ -758,6 +884,13 @@ static int discover_arenas(struct btt *btt) 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) |