1 files changed, 231 insertions, 0 deletions

diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
new file mode 100644
index 000000000..2bcb3495e
--- /dev/null
+++ b/block/blk-rq-qos.h
@@ -0,0 +1,231 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef RQ_QOS_H
+#define RQ_QOS_H
+
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/blk_types.h>
+#include <linux/atomic.h>
+#include <linux/wait.h>
+#include <linux/blk-mq.h>
+
+#include "blk-mq-debugfs.h"
+
+struct blk_mq_debugfs_attr;
+
+enum rq_qos_id {
+	RQ_QOS_WBT,
+	RQ_QOS_LATENCY,
+	RQ_QOS_COST,
+};
+
+struct rq_wait {
+	wait_queue_head_t wait;
+	atomic_t inflight;
+};
+
+struct rq_qos {
+	struct rq_qos_ops *ops;
+	struct request_queue *q;
+	enum rq_qos_id id;
+	struct rq_qos *next;
+#ifdef CONFIG_BLK_DEBUG_FS
+	struct dentry *debugfs_dir;
+#endif
+};
+
+struct rq_qos_ops {
+	void (*throttle)(struct rq_qos *, struct bio *);
+	void (*track)(struct rq_qos *, struct request *, struct bio *);
+	void (*merge)(struct rq_qos *, struct request *, struct bio *);
+	void (*issue)(struct rq_qos *, struct request *);
+	void (*requeue)(struct rq_qos *, struct request *);
+	void (*done)(struct rq_qos *, struct request *);
+	void (*done_bio)(struct rq_qos *, struct bio *);
+	void (*cleanup)(struct rq_qos *, struct bio *);
+	void (*queue_depth_changed)(struct rq_qos *);
+	void (*exit)(struct rq_qos *);
+	const struct blk_mq_debugfs_attr *debugfs_attrs;
+};
+
+struct rq_depth {
+	unsigned int max_depth;
+
+	int scale_step;
+	bool scaled_max;
+
+	unsigned int queue_depth;
+	unsigned int default_depth;
+};
+
+static inline struct rq_qos *rq_qos_id(struct request_queue *q,
+				       enum rq_qos_id id)
+{
+	struct rq_qos *rqos;
+	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
+		if (rqos->id == id)
+			break;
+	}
+	return rqos;
+}
+
+static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
+{
+	return rq_qos_id(q, RQ_QOS_WBT);
+}
+
+static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
+{
+	return rq_qos_id(q, RQ_QOS_LATENCY);
+}
+
+static inline const char *rq_qos_id_to_name(enum rq_qos_id id)
+{
+	switch (id) {
+	case RQ_QOS_WBT:
+		return "wbt";
+	case RQ_QOS_LATENCY:
+		return "latency";
+	case RQ_QOS_COST:
+		return "cost";
+	}
+	return "unknown";
+}
+
+static inline void rq_wait_init(struct rq_wait *rq_wait)
+{
+	atomic_set(&rq_wait->inflight, 0);
+	init_waitqueue_head(&rq_wait->wait);
+}
+
+static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
+{
+	/*
+	 * No IO can be in-flight when adding rqos, so freeze queue, which
+	 * is fine since we only support rq_qos for blk-mq queue.
+	 *
+	 * Reuse ->queue_lock for protecting against other concurrent
+	 * rq_qos adding/deleting
+	 */
+	blk_mq_freeze_queue(q);
+
+	spin_lock_irq(&q->queue_lock);
+	rqos->next = q->rq_qos;
+	q->rq_qos = rqos;
+	spin_unlock_irq(&q->queue_lock);
+
+	blk_mq_unfreeze_queue(q);
+
+	if (rqos->ops->debugfs_attrs)
+		blk_mq_debugfs_register_rqos(rqos);
+}
+
+static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
+{
+	struct rq_qos **cur;
+
+	/*
+	 * See comment in rq_qos_add() about freezing queue & using
+	 * ->queue_lock.
+	 */
+	blk_mq_freeze_queue(q);
+
+	spin_lock_irq(&q->queue_lock);
+	for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
+		if (*cur == rqos) {
+			*cur = rqos->next;
+			break;
+		}
+	}
+	spin_unlock_irq(&q->queue_lock);
+
+	blk_mq_unfreeze_queue(q);
+
+	blk_mq_debugfs_unregister_rqos(rqos);
+}
+
+typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
+typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
+
+void rq_qos_wait(struct rq_wait *rqw, void *private_data,
+		 acquire_inflight_cb_t *acquire_inflight_cb,
+		 cleanup_cb_t *cleanup_cb);
+bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
+bool rq_depth_scale_up(struct rq_depth *rqd);
+bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
+bool rq_depth_calc_max_depth(struct rq_depth *rqd);
+
+void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
+void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
+void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
+void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
+void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
+void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
+void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
+void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
+void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
+
+static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
+{
+	if (q->rq_qos)
+		__rq_qos_cleanup(q->rq_qos, bio);
+}
+
+static inline void rq_qos_done(struct request_queue *q, struct request *rq)
+{
+	if (q->rq_qos)
+		__rq_qos_done(q->rq_qos, rq);
+}
+
+static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
+{
+	if (q->rq_qos)
+		__rq_qos_issue(q->rq_qos, rq);
+}
+
+static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
+{
+	if (q->rq_qos)
+		__rq_qos_requeue(q->rq_qos, rq);
+}
+
+static inline void rq_qos_done_bio(struct request_queue *q, struct bio *bio)
+{
+	if (q->rq_qos)
+		__rq_qos_done_bio(q->rq_qos, bio);
+}
+
+static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
+{
+	/*
+	 * BIO_TRACKED lets controllers know that a bio went through the
+	 * normal rq_qos path.
+	 */
+	bio_set_flag(bio, BIO_TRACKED);
+	if (q->rq_qos)
+		__rq_qos_throttle(q->rq_qos, bio);
+}
+
+static inline void rq_qos_track(struct request_queue *q, struct request *rq,
+				struct bio *bio)
+{
+	if (q->rq_qos)
+		__rq_qos_track(q->rq_qos, rq, bio);
+}
+
+static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
+				struct bio *bio)
+{
+	if (q->rq_qos)
+		__rq_qos_merge(q->rq_qos, rq, bio);
+}
+
+static inline void rq_qos_queue_depth_changed(struct request_queue *q)
+{
+	if (q->rq_qos)
+		__rq_qos_queue_depth_changed(q->rq_qos);
+}
+
+void rq_qos_exit(struct request_queue *);
+
+#endif