static int __smq_writeback_work(struct smq_policy *mq, dm_oblock_t *oblock,
dm_cblock_t *cblock, bool critical_only)
{
struct entry *e = NULL;
bool target_met = clean_target_met(mq, critical_only);
if (critical_only)
/*
* Always try and keep the bottom level clean.
*/
e = pop_old(mq, &mq->dirty, target_met ? 1u : mq->dirty.nr_levels);
else
e = pop_old(mq, &mq->dirty, mq->dirty.nr_levels);
if (!e)
return -ENODATA;
*oblock = e->oblock;
*cblock = infer_cblock(mq, e);
e->dirty = false;
push_new(mq, e);
return 0;
}
static void insert_in_cache(struct smq_policy *mq, dm_oblock_t oblock,
struct policy_locker *locker,
struct policy_result *result, enum promote_result pr)
{
int r;
struct entry *e;
if (allocator_empty(&mq->cache_alloc)) {
result->op = POLICY_REPLACE;
r = demote_cblock(mq, locker, &result->old_oblock);
if (r) {
result->op = POLICY_MISS;
return;
}
} else
result->op = POLICY_NEW;
e = alloc_entry(&mq->cache_alloc);
BUG_ON(!e);
e->oblock = oblock;
if (pr == PROMOTE_TEMPORARY)
push(mq, e);
else
push_new(mq, e);
result->cblock = infer_cblock(mq, e);
}
static void requeue(struct smq_policy *mq, struct entry *e)
{
struct entry *sentinel;
if (!test_and_set_bit(from_cblock(infer_cblock(mq, e)), mq->cache_hit_bits)) {
if (e->dirty) {
sentinel = writeback_sentinel(mq, e->level);
q_requeue_before(&mq->dirty, sentinel, e, 1u);
} else {
sentinel = demote_sentinel(mq, e->level);
q_requeue_before(&mq->clean, sentinel, e, 1u);
}
}
}
static int smq_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
{
int r;
unsigned long flags;
struct smq_policy *mq = to_smq_policy(p);
struct entry *e;
spin_lock_irqsave(&mq->lock, flags);
e = h_lookup(&mq->table, oblock);
if (e) {
*cblock = infer_cblock(mq, e);
r = 0;
} else
r = -ENOENT;
spin_unlock_irqrestore(&mq->lock, flags);
return r;
}
static int smq_save_hints(struct smq_policy *mq, struct queue *q,
policy_walk_fn fn, void *context)
{
int r;
unsigned level;
struct entry *e;
for (level = 0; level < q->nr_levels; level++)
for (e = l_head(q->es, q->qs + level); e; e = l_next(q->es, e)) {
if (!e->sentinel) {
r = fn(context, infer_cblock(mq, e),
e->oblock, e->level);
if (r)
return r;
}
}
return 0;
}
static int smq_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
{
int r;
struct smq_policy *mq = to_smq_policy(p);
struct entry *e;
if (!mutex_trylock(&mq->lock))
return -EWOULDBLOCK;
e = h_lookup(&mq->table, oblock);
if (e) {
*cblock = infer_cblock(mq, e);
r = 0;
} else
r = -ENOENT;
mutex_unlock(&mq->lock);
return r;
}
/*
* Looks the oblock up in the hash table, then decides whether to put in
* pre_cache, or cache etc.
*/
static int map(struct smq_policy *mq, struct bio *bio, dm_oblock_t oblock,
bool can_migrate, bool fast_promote,
struct policy_locker *locker, struct policy_result *result)
{
struct entry *e, *hs_e;
enum promote_result pr;
hs_e = update_hotspot_queue(mq, oblock, bio);
e = h_lookup(&mq->table, oblock);
if (e) {
stats_level_accessed(&mq->cache_stats, e->level);
requeue(mq, e);
result->op = POLICY_HIT;
result->cblock = infer_cblock(mq, e);
} else {
stats_miss(&mq->cache_stats);
pr = should_promote(mq, hs_e, bio, fast_promote);
if (pr == PROMOTE_NOT)
result->op = POLICY_MISS;
else {
if (!can_migrate) {
result->op = POLICY_MISS;
return -EWOULDBLOCK;
}
insert_in_cache(mq, oblock, locker, result, pr);
}
}
return 0;
}
