Merge tag 'block-5.6-2020-02-05' of git://git.kernel.dk/linux-block

Pull more block updates from Jens Axboe:
 "Some later arrivals, but all fixes at this point:

   - bcache fix series (Coly)

   - Series of BFQ fixes (Paolo)

   - NVMe pull request from Keith with a few minor NVMe fixes

   - Various little tweaks"

* tag 'block-5.6-2020-02-05' of git://git.kernel.dk/linux-block: (23 commits)
  nvmet: update AEN list and array at one place
  nvmet: Fix controller use after free
  nvmet: Fix error print message at nvmet_install_queue function
  brd: check and limit max_part par
  nvme-pci: remove nvmeq->tags
  nvmet: fix dsm failure when payload does not match sgl descriptor
  nvmet: Pass lockdep expression to RCU lists
  block, bfq: clarify the goal of bfq_split_bfqq()
  block, bfq: get a ref to a group when adding it to a service tree
  block, bfq: remove ifdefs from around gets/puts of bfq groups
  block, bfq: extend incomplete name of field on_st
  block, bfq: get extra ref to prevent a queue from being freed during a group move
  block, bfq: do not insert oom queue into position tree
  block, bfq: do not plug I/O for bfq_queues with no proc refs
  bcache: check return value of prio_read()
  bcache: fix incorrect data type usage in btree_flush_write()
  bcache: add readahead cache policy options via sysfs interface
  bcache: explicity type cast in bset_bkey_last()
  bcache: fix memory corruption in bch_cache_accounting_clear()
  xen/blkfront: limit allocated memory size to actual use case
  ...

4 files changed, 54 insertions, 15 deletions

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index e1419edde2ec..09b69a3ed490 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -332,7 +332,7 @@ static void bfqg_put(struct bfq_group *bfqg)
 		kfree(bfqg);
 }
 
-static void bfqg_and_blkg_get(struct bfq_group *bfqg)
+void bfqg_and_blkg_get(struct bfq_group *bfqg)
 {
 	/* see comments in bfq_bic_update_cgroup for why refcounting bfqg */
 	bfqg_get(bfqg);
@@ -651,9 +651,15 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		bfq_bfqq_expire(bfqd, bfqd->in_service_queue,
 				false, BFQQE_PREEMPTED);
 
+	/*
+	 * get extra reference to prevent bfqq from being freed in
+	 * next possible deactivate
+	 */
+	bfqq->ref++;
+
 	if (bfq_bfqq_busy(bfqq))
 		bfq_deactivate_bfqq(bfqd, bfqq, false, false);
-	else if (entity->on_st)
+	else if (entity->on_st_or_in_serv)
 		bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
 	bfqg_and_blkg_put(bfqq_group(bfqq));
 
@@ -670,6 +676,8 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 
 	if (!bfqd->in_service_queue && !bfqd->rq_in_driver)
 		bfq_schedule_dispatch(bfqd);
+	/* release extra ref taken above */
+	bfq_put_queue(bfqq);
 }
 
 /**
@@ -1398,6 +1406,10 @@ struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
 	return bfqq->bfqd->root_group;
 }
 
+void bfqg_and_blkg_get(struct bfq_group *bfqg) {}
+
+void bfqg_and_blkg_put(struct bfq_group *bfqg) {}
+
 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
 {
 	struct bfq_group *bfqg;
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 4686b68b48b4..8c436abfaf14 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -613,6 +613,10 @@ bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq)
 		bfqq->pos_root = NULL;
 	}
 
+	/* oom_bfqq does not participate in queue merging */
+	if (bfqq == &bfqd->oom_bfqq)
+		return;
+
 	/*
 	 * bfqq cannot be merged any longer (see comments in
 	 * bfq_setup_cooperator): no point in adding bfqq into the
@@ -1055,7 +1059,7 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd,
 
 static int bfqq_process_refs(struct bfq_queue *bfqq)
 {
-	return bfqq->ref - bfqq->allocated - bfqq->entity.on_st -
+	return bfqq->ref - bfqq->allocated - bfqq->entity.on_st_or_in_serv -
 		(bfqq->weight_counter != NULL);
 }
 
@@ -3443,6 +3447,10 @@ static void bfq_dispatch_remove(struct request_queue *q, struct request *rq)
 static bool idling_needed_for_service_guarantees(struct bfq_data *bfqd,
 						 struct bfq_queue *bfqq)
 {
+	/* No point in idling for bfqq if it won't get requests any longer */
+	if (unlikely(!bfqq_process_refs(bfqq)))
+		return false;
+
 	return (bfqq->wr_coeff > 1 &&
 		(bfqd->wr_busy_queues <
 		 bfq_tot_busy_queues(bfqd) ||
@@ -4076,6 +4084,10 @@ static bool idling_boosts_thr_without_issues(struct bfq_data *bfqd,
 		bfqq_sequential_and_IO_bound,
 		idling_boosts_thr;
 
+	/* No point in idling for bfqq if it won't get requests any longer */
+	if (unlikely(!bfqq_process_refs(bfqq)))
+		return false;
+
 	bfqq_sequential_and_IO_bound = !BFQQ_SEEKY(bfqq) &&
 		bfq_bfqq_IO_bound(bfqq) && bfq_bfqq_has_short_ttime(bfqq);
 
@@ -4169,6 +4181,10 @@ static bool bfq_better_to_idle(struct bfq_queue *bfqq)
 	struct bfq_data *bfqd = bfqq->bfqd;
 	bool idling_boosts_thr_with_no_issue, idling_needed_for_service_guar;
 
+	/* No point in idling for bfqq if it won't get requests any longer */
+	if (unlikely(!bfqq_process_refs(bfqq)))
+		return false;
+
 	if (unlikely(bfqd->strict_guarantees))
 		return true;
 
@@ -4809,9 +4825,7 @@ void bfq_put_queue(struct bfq_queue *bfqq)
 {
 	struct bfq_queue *item;
 	struct hlist_node *n;
-#ifdef CONFIG_BFQ_GROUP_IOSCHED
 	struct bfq_group *bfqg = bfqq_group(bfqq);
-#endif
 
 	if (bfqq->bfqd)
 		bfq_log_bfqq(bfqq->bfqd, bfqq, "put_queue: %p %d",
@@ -4884,9 +4898,7 @@ void bfq_put_queue(struct bfq_queue *bfqq)
 		bfqq->bfqd->last_completed_rq_bfqq = NULL;
 
 	kmem_cache_free(bfq_pool, bfqq);
-#ifdef CONFIG_BFQ_GROUP_IOSCHED
 	bfqg_and_blkg_put(bfqg);
-#endif
 }
 
 static void bfq_put_cooperator(struct bfq_queue *bfqq)
@@ -5967,6 +5979,8 @@ static void bfq_finish_requeue_request(struct request *rq)
 }
 
 /*
+ * Removes the association between the current task and bfqq, assuming
+ * that bic points to the bfq iocontext of the task.
  * Returns NULL if a new bfqq should be allocated, or the old bfqq if this
  * was the last process referring to that bfqq.
  */
@@ -6374,10 +6388,10 @@ static void bfq_exit_queue(struct elevator_queue *e)
 
 	hrtimer_cancel(&bfqd->idle_slice_timer);
 
-#ifdef CONFIG_BFQ_GROUP_IOSCHED
 	/* release oom-queue reference to root group */
 	bfqg_and_blkg_put(bfqd->root_group);
 
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
 	blkcg_deactivate_policy(bfqd->queue, &blkcg_policy_bfq);
 #else
 	spin_lock_irq(&bfqd->lock);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 8526f20c53bc..d1233af9c684 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -150,7 +150,7 @@ struct bfq_entity {
 	 * Flag, true if the entity is on a tree (either the active or
 	 * the idle one of its service_tree) or is in service.
 	 */
-	bool on_st;
+	bool on_st_or_in_serv;
 
 	/* B-WF2Q+ start and finish timestamps [sectors/weight] */
 	u64 start, finish;
@@ -921,6 +921,7 @@ struct bfq_group {
 
 #else
 struct bfq_group {
+	struct bfq_entity entity;
 	struct bfq_sched_data sched_data;
 
 	struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
@@ -984,6 +985,7 @@ struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
 struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
+void bfqg_and_blkg_get(struct bfq_group *bfqg);
 void bfqg_and_blkg_put(struct bfq_group *bfqg);
 
 #ifdef CONFIG_BFQ_GROUP_IOSCHED
diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index ffe9ce9faa89..eb0e2a6daabe 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -533,7 +533,9 @@ static void bfq_get_entity(struct bfq_entity *entity)
 		bfqq->ref++;
 		bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d",
 			     bfqq, bfqq->ref);
-	}
+	} else
+		bfqg_and_blkg_get(container_of(entity, struct bfq_group,
+					       entity));
 }
 
 /**
@@ -645,10 +647,16 @@ static void bfq_forget_entity(struct bfq_service_tree *st,
 {
 	struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
 
-	entity->on_st = false;
+	entity->on_st_or_in_serv = false;
 	st->wsum -= entity->weight;
-	if (bfqq && !is_in_service)
+	if (is_in_service)
+		return;
+
+	if (bfqq)
 		bfq_put_queue(bfqq);
+	else
+		bfqg_and_blkg_put(container_of(entity, struct bfq_group,
+					       entity));
 }
 
 /**
@@ -999,7 +1007,7 @@ static void __bfq_activate_entity(struct bfq_entity *entity,
 		 */
 		bfq_get_entity(entity);
 
-		entity->on_st = true;
+		entity->on_st_or_in_serv = true;
 	}
 
 #ifdef CONFIG_BFQ_GROUP_IOSCHED
@@ -1165,7 +1173,10 @@ bool __bfq_deactivate_entity(struct bfq_entity *entity, bool ins_into_idle_tree)
 	struct bfq_service_tree *st;
 	bool is_in_service;
 
-	if (!entity->on_st) /* entity never activated, or already inactive */
+	if (!entity->on_st_or_in_serv) /*
+					* entity never activated, or
+					* already inactive
+					*/
 		return false;
 
 	/*
@@ -1620,7 +1631,7 @@ bool __bfq_bfqd_reset_in_service(struct bfq_data *bfqd)
 	 * service tree either, then release the service reference to
 	 * the queue it represents (taken with bfq_get_entity).
 	 */
-	if (!in_serv_entity->on_st) {
+	if (!in_serv_entity->on_st_or_in_serv) {
 		/*
 		 * If no process is referencing in_serv_bfqq any
 		 * longer, then the service reference may be the only