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authorRoss Zwisler <ross.zwisler@linux.intel.com>2018-02-03 00:26:10 -0700
committerRoss Zwisler <ross.zwisler@linux.intel.com>2018-02-03 00:26:10 -0700
commitd121f07691415df824e6b60520f782f6d13b3c81 (patch)
tree422ad3cc6fd631604fef4e469e49bacba8202e52 /drivers/nvdimm/btt.c
parent59858d3d54cfad1f8db67c2c07e4dd33bb6ed955 (diff)
parent569d0365f571fa6421a5c80bc30d1b2cdab857fe (diff)
Merge branch 'for-4.16/dax' into libnvdimm-for-next
Diffstat (limited to 'drivers/nvdimm/btt.c')
-rw-r--r--drivers/nvdimm/btt.c201
1 files changed, 167 insertions, 34 deletions
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 5860f99113c6..2ef544f10ec8 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);
@@ -651,8 +774,7 @@ 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 */
@@ -669,6 +791,10 @@ 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;
}
@@ -759,6 +885,13 @@ 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;
+ }
+
ret = btt_freelist_init(arena);
if (ret)
goto out;

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