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-rw-r--r--block/blk-rq-qos.h231
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