bcache: Convert bucket_wait to wait_queue_head_t

At one point we did do fancy asynchronous waiting stuff with
bucket_wait, but that's all gone (and bucket_wait is used a lot less
than it used to be). So use the standard primitives.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

6 files changed, 70 insertions, 67 deletions

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index e033b0203b68..1b64e662e81b 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -339,7 +339,7 @@ static int bch_allocator_thread(void *arg)
                         allocator_wait(ca, !fifo_full(&ca->free));
 
                         fifo_push(&ca->free, bucket);
-                        closure_wake_up(&ca->set->bucket_wait);
+                        wake_up(&ca->set->bucket_wait);
                 }
 
                 /*
@@ -365,16 +365,41 @@ static int bch_allocator_thread(void *arg)
         }
 }
 
-long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl)
+long bch_bucket_alloc(struct cache *ca, unsigned watermark, bool wait)
 {
-        long r = -1;
-again:
+        DEFINE_WAIT(w);
+        struct bucket *b;
+        long r;
+
+        /* fastpath */
+        if (fifo_used(&ca->free) > ca->watermark[watermark]) {
+                fifo_pop(&ca->free, r);
+                goto out;
+        }
+
+        if (!wait)
+                return -1;
+
+        while (1) {
+                if (fifo_used(&ca->free) > ca->watermark[watermark]) {
+                        fifo_pop(&ca->free, r);
+                        break;
+                }
+
+                prepare_to_wait(&ca->set->bucket_wait, &w,
+                                TASK_UNINTERRUPTIBLE);
+
+                mutex_unlock(&ca->set->bucket_lock);
+                schedule();
+                mutex_lock(&ca->set->bucket_lock);
+        }
+
+        finish_wait(&ca->set->bucket_wait, &w);
+out:
         wake_up_process(ca->alloc_thread);
 
-        if (fifo_used(&ca->free) > ca->watermark[watermark] &&
-            fifo_pop(&ca->free, r)) {
-                struct bucket *b = ca->buckets + r;
 #ifdef CONFIG_BCACHE_EDEBUG
+        {
                 size_t iter;
                 long i;
 
@@ -387,36 +412,23 @@ again:
                         BUG_ON(i == r);
                 fifo_for_each(i, &ca->unused, iter)
                         BUG_ON(i == r);
-#endif
-                BUG_ON(atomic_read(&b->pin) != 1);
-
-                SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
-
-                if (watermark <= WATERMARK_METADATA) {
-                        SET_GC_MARK(b, GC_MARK_METADATA);
-                        b->prio = BTREE_PRIO;
-                } else {
-                        SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
-                        b->prio = INITIAL_PRIO;
-                }
-
-                return r;
         }
+#endif
+        b = ca->buckets + r;
 
-        trace_bcache_alloc_fail(ca);
+        BUG_ON(atomic_read(&b->pin) != 1);
 
-        if (cl) {
-                closure_wait(&ca->set->bucket_wait, cl);
+        SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
 
-                if (closure_blocking(cl)) {
-                        mutex_unlock(&ca->set->bucket_lock);
-                        closure_sync(cl);
-                        mutex_lock(&ca->set->bucket_lock);
-                        goto again;
-                }
+        if (watermark <= WATERMARK_METADATA) {
+                SET_GC_MARK(b, GC_MARK_METADATA);
+                b->prio = BTREE_PRIO;
+        } else {
+                SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
+                b->prio = INITIAL_PRIO;
         }
 
-        return -1;
+        return r;
 }
 
 void bch_bucket_free(struct cache_set *c, struct bkey *k)
@@ -433,7 +445,7 @@ void bch_bucket_free(struct cache_set *c, struct bkey *k)
 }
 
 int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
-                           struct bkey *k, int n, struct closure *cl)
+                           struct bkey *k, int n, bool wait)
 {
         int i;
 
@@ -446,7 +458,7 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 
         for (i = 0; i < n; i++) {
                 struct cache *ca = c->cache_by_alloc[i];
-                long b = bch_bucket_alloc(ca, watermark, cl);
+                long b = bch_bucket_alloc(ca, watermark, wait);
 
                 if (b == -1)
                         goto err;
@@ -466,11 +478,11 @@ err:
 }
 
 int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
-                         struct bkey *k, int n, struct closure *cl)
+                         struct bkey *k, int n, bool wait)
 {
         int ret;
         mutex_lock(&c->bucket_lock);
-        ret = __bch_bucket_alloc_set(c, watermark, k, n, cl);
+        ret = __bch_bucket_alloc_set(c, watermark, k, n, wait);
         mutex_unlock(&c->bucket_lock);
         return ret;
 }
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index c1c44191afb1..d3520748bc27 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -750,7 +750,7 @@ struct cache_set {
          * written.
          */
         atomic_t                prio_blocked;
-        struct closure_waitlist bucket_wait;
+        wait_queue_head_t       bucket_wait;
 
         /*
          * For any bio we don't skip we subtract the number of sectors from
@@ -1162,13 +1162,13 @@ uint8_t bch_inc_gen(struct cache *, struct bucket *);
 void bch_rescale_priorities(struct cache_set *, int);
 bool bch_bucket_add_unused(struct cache *, struct bucket *);
 
-long bch_bucket_alloc(struct cache *, unsigned, struct closure *);
+long bch_bucket_alloc(struct cache *, unsigned, bool);
 void bch_bucket_free(struct cache_set *, struct bkey *);
 
 int __bch_bucket_alloc_set(struct cache_set *, unsigned,
-                           struct bkey *, int, struct closure *);
+                           struct bkey *, int, bool);
 int bch_bucket_alloc_set(struct cache_set *, unsigned,
-                         struct bkey *, int, struct closure *);
+                         struct bkey *, int, bool);
 
 __printf(2, 3)
 bool bch_cache_set_error(struct cache_set *, const char *, ...);
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 4d50f1e7006e..935d90df397b 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -813,7 +813,7 @@ static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k)
  * cannibalize_bucket() will take. This means every time we unlock the root of
  * the btree, we need to release this lock if we have it held.
  */
-void bch_cannibalize_unlock(struct cache_set *c, struct closure *cl)
+void bch_cannibalize_unlock(struct cache_set *c)
 {
         if (c->try_harder == current) {
                 bch_time_stats_update(&c->try_harder_time, c->try_harder_start);
@@ -995,15 +995,14 @@ static void btree_node_free(struct btree *b)
         mutex_unlock(&b->c->bucket_lock);
 }
 
-struct btree *bch_btree_node_alloc(struct cache_set *c, int level,
-                                   struct closure *cl)
+struct btree *bch_btree_node_alloc(struct cache_set *c, int level)
 {
         BKEY_PADDED(key) k;
         struct btree *b = ERR_PTR(-EAGAIN);
 
         mutex_lock(&c->bucket_lock);
 retry:
-        if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, cl))
+        if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, true))
                 goto err;
 
         SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
@@ -1036,10 +1035,9 @@ err:
         return b;
 }
 
-static struct btree *btree_node_alloc_replacement(struct btree *b,
-                                                  struct closure *cl)
+static struct btree *btree_node_alloc_replacement(struct btree *b)
 {
-        struct btree *n = bch_btree_node_alloc(b->c, b->level, cl);
+        struct btree *n = bch_btree_node_alloc(b->c, b->level);
         if (!IS_ERR_OR_NULL(n))
                 bch_btree_sort_into(b, n);
 
@@ -1152,7 +1150,7 @@ static struct btree *btree_gc_alloc(struct btree *b, struct bkey *k)
          * bch_bucket_alloc_set(), or we'd risk deadlock - so we don't pass it
          * our closure.
          */
-        struct btree *n = btree_node_alloc_replacement(b, NULL);
+        struct btree *n = btree_node_alloc_replacement(b);
 
         if (!IS_ERR_OR_NULL(n)) {
                 swap(b, n);
@@ -1359,7 +1357,7 @@ static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
         int ret = 0, stale = btree_gc_mark_node(b, &keys, gc);
 
         if (b->level || stale > 10)
-                n = btree_node_alloc_replacement(b, NULL);
+                n = btree_node_alloc_replacement(b);
 
         if (!IS_ERR_OR_NULL(n))
                 swap(b, n);
@@ -1882,10 +1880,7 @@ static int btree_split(struct btree *b, struct btree_op *op,
         struct btree *n1, *n2 = NULL, *n3 = NULL;
         uint64_t start_time = local_clock();
 
-        if (b->level)
-                set_closure_blocking(&op->cl);
-
-        n1 = btree_node_alloc_replacement(b, &op->cl);
+        n1 = btree_node_alloc_replacement(b);
         if (IS_ERR(n1))
                 goto err;
 
@@ -1896,12 +1891,12 @@ static int btree_split(struct btree *b, struct btree_op *op,
 
                 trace_bcache_btree_node_split(b, n1->sets[0].data->keys);
 
-                n2 = bch_btree_node_alloc(b->c, b->level, &op->cl);
+                n2 = bch_btree_node_alloc(b->c, b->level);
                 if (IS_ERR(n2))
                         goto err_free1;
 
                 if (!b->parent) {
-                        n3 = bch_btree_node_alloc(b->c, b->level + 1, &op->cl);
+                        n3 = bch_btree_node_alloc(b->c, b->level + 1);
                         if (IS_ERR(n3))
                                 goto err_free2;
                 }
diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
index 72794ab8e8e5..d691d954730e 100644
--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -355,7 +355,7 @@ static inline void rw_unlock(bool w, struct btree *b)
                         _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__);   \
                 }                                                       \
                 rw_unlock(_w, _b);                                      \
-                bch_cannibalize_unlock(c, &(op)->cl);                   \
+                bch_cannibalize_unlock(c);                              \
                 if (_r == -ENOSPC) {                                    \
                         wait_event((c)->try_wait,                       \
                                    !(c)->try_harder);                   \
@@ -377,9 +377,9 @@ static inline bool should_split(struct btree *b)
 void bch_btree_node_read(struct btree *);
 void bch_btree_node_write(struct btree *, struct closure *);
 
-void bch_cannibalize_unlock(struct cache_set *, struct closure *);
+void bch_cannibalize_unlock(struct cache_set *);
 void bch_btree_set_root(struct btree *);
-struct btree *bch_btree_node_alloc(struct cache_set *, int, struct closure *);
+struct btree *bch_btree_node_alloc(struct cache_set *, int);
 struct btree *bch_btree_node_get(struct cache_set *, struct bkey *, int, bool);
 
 int bch_btree_insert_check_key(struct btree *, struct btree_op *,
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index d85c7001df61..26d18f4bf4a0 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -350,14 +350,8 @@ static bool bch_alloc_sectors(struct bkey *k, unsigned sectors,
         struct cache_set *c = s->op.c;
         struct open_bucket *b;
         BKEY_PADDED(key) alloc;
-        struct closure cl, *w = NULL;
         unsigned i;
 
-        if (s->writeback) {
-                closure_init_stack(&cl);
-                w = &cl;
-        }
-
         /*
          * We might have to allocate a new bucket, which we can't do with a
          * spinlock held. So if we have to allocate, we drop the lock, allocate
@@ -375,7 +369,8 @@ static bool bch_alloc_sectors(struct bkey *k, unsigned sectors,
 
                 spin_unlock(&c->data_bucket_lock);
 
-                if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, w))
+                if (bch_bucket_alloc_set(c, watermark, &alloc.key,
+                                         1, s->writeback))
                         return false;
 
                 spin_lock(&c->data_bucket_lock);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 9a164cd4058c..84398a82fbe3 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -427,7 +427,7 @@ static int __uuid_write(struct cache_set *c)
 
         lockdep_assert_held(&bch_register_lock);
 
-        if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, &cl))
+        if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, true))
                 return 1;
 
         SET_KEY_SIZE(&k.key, c->sb.bucket_size);
@@ -565,7 +565,7 @@ void bch_prio_write(struct cache *ca)
                 p->magic        = pset_magic(ca);
                 p->csum         = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
 
-                bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, &cl);
+                bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, true);
                 BUG_ON(bucket == -1);
 
                 mutex_unlock(&ca->set->bucket_lock);
@@ -1439,6 +1439,7 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
         closure_init_unlocked(&c->sb_write);
         mutex_init(&c->bucket_lock);
         init_waitqueue_head(&c->try_wait);
+        init_waitqueue_head(&c->bucket_wait);
         closure_init_unlocked(&c->uuid_write);
         spin_lock_init(&c->sort_time_lock);
         mutex_init(&c->sort_lock);
@@ -1608,7 +1609,7 @@ static void run_cache_set(struct cache_set *c)
                         goto err_unlock_gc;
 
                 err = "cannot allocate new btree root";
-                c->root = bch_btree_node_alloc(c, 0, &op.cl);
+                c->root = bch_btree_node_alloc(c, 0);
                 if (IS_ERR_OR_NULL(c->root))
                         goto err_unlock_gc;