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>

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;
 
@@ -387,7 +412,10 @@ long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl)
 			BUG_ON(i == r);
 		fifo_for_each(i, &ca->unused, iter)
 			BUG_ON(i == r);
+	}
 #endif
+	b = ca->buckets + r;
+
 	BUG_ON(atomic_read(&b->pin) != 1);
 
 	SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
@@ -401,22 +429,6 @@ long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl)
 	}
 
 	return r;
-	}
-
-	trace_bcache_alloc_fail(ca);
-
-	if (cl) {
-		closure_wait(&ca->set->bucket_wait, cl);
-
-		if (closure_blocking(cl)) {
-			mutex_unlock(&ca->set->bucket_lock);
-			closure_sync(cl);
-			mutex_lock(&ca->set->bucket_lock);
-			goto again;
-		}
-	}
-
-	return -1;
 }
 
 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 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 }
 
 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;
 }

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 *, ...);

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 @@ struct btree *bch_btree_node_alloc(struct cache_set *c, int level,
 	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;
 		}

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 *,

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);

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;