From 29380f628074a8f7179fd06a0109cd6c7eca6b99 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Mon, 28 Jun 2021 17:06:28 +0200
Subject: [PATCH 2/4] bfq: Track number of allocated requests in bfq_entity
References: bsc#1184318
Patch-mainline: Not yet, in linux-block tree as of 21/12/2021

When we want to limit number of requests used by each bfqq and also
cgroup, we need to track also number of requests used by each cgroup.
So track number of allocated requests for each bfq_entity.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 block/bfq-iosched.c |   28 ++++++++++++++++++++++------
 block/bfq-iosched.h |    5 +++--
 2 files changed, 25 insertions(+), 8 deletions(-)

--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1060,7 +1060,8 @@ bfq_bfqq_resume_state(struct bfq_queue *
 
 static int bfqq_process_refs(struct bfq_queue *bfqq)
 {
-	return bfqq->ref - bfqq->allocated - bfqq->entity.on_st_or_in_serv -
+	return bfqq->ref - bfqq->entity.allocated -
+		bfqq->entity.on_st_or_in_serv -
 		(bfqq->weight_counter != NULL);
 }
 
@@ -5422,6 +5423,22 @@ static void bfq_rq_enqueued(struct bfq_d
 	}
 }
 
+static void bfqq_request_allocated(struct bfq_queue *bfqq)
+{
+	struct bfq_entity *entity = &bfqq->entity;
+
+	for_each_entity(entity)
+		entity->allocated++;
+}
+
+static void bfqq_request_freed(struct bfq_queue *bfqq)
+{
+	struct bfq_entity *entity = &bfqq->entity;
+
+	for_each_entity(entity)
+		entity->allocated--;
+}
+
 /* returns true if it causes the idle timer to be disabled */
 static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq)
 {
@@ -5434,8 +5451,8 @@ static bool __bfq_insert_request(struct
 		 * Release the request's reference to the old bfqq
 		 * and make sure one is taken to the shared queue.
 		 */
-		new_bfqq->allocated++;
-		bfqq->allocated--;
+		bfqq_request_allocated(new_bfqq);
+		bfqq_request_freed(bfqq);
 		new_bfqq->ref++;
 		/*
 		 * If the bic associated with the process
@@ -5741,8 +5758,7 @@ static void bfq_completed_request(struct
 
 static void bfq_finish_requeue_request_body(struct bfq_queue *bfqq)
 {
-	bfqq->allocated--;
-
+	bfqq_request_freed(bfqq);
 	bfq_put_queue(bfqq);
 }
 
@@ -6148,7 +6164,7 @@ static struct bfq_queue *bfq_init_rq(str
 		}
 	}
 
-	bfqq->allocated++;
+	bfqq_request_allocated(bfqq);
 	bfqq->ref++;
 	bfq_log_bfqq(bfqd, bfqq, "get_request %p: bfqq %p, %d",
 		     rq, bfqq, bfqq->ref);
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -170,6 +170,9 @@ struct bfq_entity {
 	/* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */
 	int budget;
 
+	/* Number of requests allocated in the subtree of this entity */
+	int allocated;
+
 	/* device weight, if non-zero, it overrides the default weight of
 	 * bfq_group_data */
 	int dev_weight;
@@ -261,8 +264,6 @@ struct bfq_queue {
 	struct request *next_rq;
 	/* number of sync and async requests queued */
 	int queued[2];
-	/* number of requests currently allocated */
-	int allocated;
 	/* number of pending metadata requests */
 	int meta_pending;
 	/* fifo list of requests in sort_list */