bcache: fifo improvements

3 files changed, 27 insertions, 40 deletions

diff --git a/drivers/md/bcache/fifo.h b/drivers/md/bcache/fifo.h
index 8bd6168aea06..32a17c92b698 100644
--- a/drivers/md/bcache/fifo.h
+++ b/drivers/md/bcache/fifo.h
@@ -18,7 +18,7 @@
 	if ((fifo)->size) {						\
 		size_t _allocated_size, _bytes;				\
 									\
-		_allocated_size = roundup_pow_of_two((fifo)->size + 1);	\
+		_allocated_size = roundup_pow_of_two((fifo)->size);	\
 		_bytes = _allocated_size * sizeof(*(fifo)->data);	\
 									\
 		(fifo)->mask = _allocated_size - 1;			\
@@ -56,77 +56,64 @@ do {									\
 		fifo_push(dest, _t);					\
 } while (0)
 
-#define fifo_used(fifo)		(((fifo)->back - (fifo)->front) & (fifo)->mask)
+#define fifo_used(fifo)		(((fifo)->back - (fifo)->front))
 #define fifo_free(fifo)		((fifo)->size - fifo_used(fifo))
 
-#define fifo_empty(fifo)	(!fifo_used(fifo))
-#define fifo_full(fifo)		(!fifo_free(fifo))
+#define fifo_empty(fifo)	((fifo)->front == (fifo)->back)
+#define fifo_full(fifo)		(fifo_used(fifo) == (fifo)->size)
 
-#define fifo_front(fifo)	((fifo)->data[(fifo)->front])
-#define fifo_back(fifo)							\
-	((fifo)->data[((fifo)->back - 1) & (fifo)->mask])
+#define fifo_peek_front(fifo)	((fifo)->data[(fifo)->front & (fifo)->mask])
+#define fifo_peek_back(fifo)	((fifo)->data[((fifo)->back - 1) & (fifo)->mask])
 
-#define fifo_entry_idx(fifo, p)	(((p) - &fifo_front(fifo)) & (fifo)->mask)
+#define fifo_entry_idx(fifo, p)	(((p) - &fifo_peek_front(fifo)) & (fifo)->mask)
 
 #define fifo_push_back(fifo, i)						\
 ({									\
 	bool _r = !fifo_full((fifo));					\
-	if (_r) {							\
-		(fifo)->data[(fifo)->back++] = (i);			\
-		(fifo)->back &= (fifo)->mask;				\
-	}								\
+	if (_r)								\
+		(fifo)->data[(fifo)->back++ & (fifo)->mask] = (i);	\
 	_r;								\
 })
 
 #define fifo_pop_front(fifo, i)						\
 ({									\
 	bool _r = !fifo_empty((fifo));					\
-	if (_r) {							\
-		(i) = (fifo)->data[(fifo)->front++];			\
-		(fifo)->front &= (fifo)->mask;				\
-	}								\
+	if (_r)								\
+		(i) = (fifo)->data[(fifo)->front++ & (fifo)->mask];	\
 	_r;								\
 })
 
 #define fifo_push_front(fifo, i)					\
 ({									\
 	bool _r = !fifo_full((fifo));					\
-	if (_r) {							\
-		--(fifo)->front;					\
-		(fifo)->front &= (fifo)->mask;				\
-		(fifo)->data[(fifo)->front] = (i);			\
-	}								\
+	if (_r)								\
+		(fifo)->data[--(fifo)->front & (fifo)->mask] = (i);	\
 	_r;								\
 })
 
 #define fifo_pop_back(fifo, i)						\
 ({									\
 	bool _r = !fifo_empty((fifo));					\
-	if (_r) {							\
-		--(fifo)->back;						\
-		(fifo)->back &= (fifo)->mask;				\
-		(i) = (fifo)->data[(fifo)->back]			\
-	}								\
+	if (_r)								\
+		(i) = (fifo)->data[--(fifo)->back & (fifo)->mask]	\
 	_r;								\
 })
 
 #define fifo_push(fifo, i)	fifo_push_back(fifo, (i))
 #define fifo_pop(fifo, i)	fifo_pop_front(fifo, (i))
-
-#define fifo_peek_front(fifo)	((fifo)->data[(fifo)->front])
 #define fifo_peek(fifo)		fifo_peek_front(fifo)
 
 #define fifo_for_each_entry(_entry, _fifo, _iter)			\
 	for (_iter = (_fifo)->front;					\
 	     ((_iter != (_fifo)->back) &&				\
-	      (_entry = (_fifo)->data[(_iter)], true));			\
-	     _iter = ((_iter) + 1) & (_fifo)->mask)
+	      (_entry = (_fifo)->data[(_iter) & (_fifo)->mask], true));	\
+	     _iter++)
 
 #define fifo_for_each_entry_ptr(_ptr, _fifo, _iter)			\
 	for (_iter = (_fifo)->front;					\
 	     ((_iter != (_fifo)->back) &&				\
-	      (_ptr = &(_fifo)->data[(_iter)], true));			\
-	     _iter = ((_iter) + 1) & (_fifo)->mask)
+	      (_ptr = &(_fifo)->data[(_iter) & (_fifo)->mask], true));	\
+	     _iter++)
 
 #endif /* _BCACHE_FIFO_H */
 
diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index 164e68879cb9..c900f4c131f1 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -911,7 +911,7 @@ static void __bch_journal_next_entry(struct journal *j)
 	 * incremented for last_seq() to be calculated correctly
 	 */
 	BUG_ON(!fifo_push(&j->pin, pin_list));
-	p = &fifo_back(&j->pin);
+	p = &fifo_peek_back(&j->pin);
 
 	INIT_LIST_HEAD(&p->list);
 	atomic_set(&p->count, 1);
@@ -970,7 +970,7 @@ static enum {
 	buf->data->u64s		= cpu_to_le32(old.cur_entry_offset);
 	buf->data->last_seq	= cpu_to_le64(last_seq(j));
 
-	atomic_dec_bug(&fifo_back(&j->pin).count);
+	atomic_dec_bug(&fifo_peek_back(&j->pin).count);
 	__bch_journal_next_entry(j);
 
 	spin_unlock(&j->lock);
@@ -1181,7 +1181,7 @@ void bch_journal_start(struct cache_set *c)
 		struct journal_entry_pin_list pin_list, *p;
 
 		BUG_ON(!fifo_push(&j->pin, pin_list));
-		p = &fifo_back(&j->pin);
+		p = &fifo_peek_back(&j->pin);
 
 		INIT_LIST_HEAD(&p->list);
 		atomic_set(&p->count, 0);
@@ -1206,7 +1206,7 @@ void bch_journal_start(struct cache_set *c)
 					JOURNAL_ENTRY_JOURNAL_SEQ_BLACKLISTED,
 					0, 0);
 
-			__journal_pin_add(j, &fifo_back(&j->pin), &bl->pin,
+			__journal_pin_add(j, &fifo_peek_back(&j->pin), &bl->pin,
 					  journal_seq_blacklist_flush);
 			bl->written = true;
 		}
@@ -1370,8 +1370,8 @@ static void journal_reclaim_fast(struct journal *j)
 	 * Unpin journal entries whose reference counts reached zero, meaning
 	 * all btree nodes got written out
 	 */
-	while (!atomic_read(&fifo_front(&j->pin).count)) {
-		BUG_ON(!list_empty(&fifo_front(&j->pin).list));
+	while (!atomic_read(&fifo_peek_front(&j->pin).count)) {
+		BUG_ON(!list_empty(&fifo_peek_front(&j->pin).list));
 		BUG_ON(!fifo_pop(&j->pin, temp));
 	}
 }
@@ -1384,7 +1384,7 @@ journal_get_next_pin(struct journal *j, u64 seq_to_flush)
 	unsigned iter;
 
 	/* so we don't iterate over empty fifo entries below: */
-	if (!atomic_read(&fifo_front(&j->pin).count)) {
+	if (!atomic_read(&fifo_peek_front(&j->pin).count)) {
 		spin_lock(&j->lock);
 		journal_reclaim_fast(j);
 		spin_unlock(&j->lock);
diff --git a/drivers/md/bcache/journal.h b/drivers/md/bcache/journal.h
index c2bb4ab708f1..7fc789a9382a 100644
--- a/drivers/md/bcache/journal.h
+++ b/drivers/md/bcache/journal.h
@@ -236,7 +236,7 @@ static inline void bch_journal_set_replay_done(struct journal *j)
 {
 	spin_lock(&j->lock);
 	set_bit(JOURNAL_REPLAY_DONE, &j->flags);
-	j->cur_pin_list = &fifo_back(&j->pin);
+	j->cur_pin_list = &fifo_peek_back(&j->pin);
 	spin_unlock(&j->lock);
 }