[PATCH 02/30] blk-mq: improve the blk_mq_init_allocated_queue interface

Christoph Hellwig
2021-06-02T06:57:43Z

Don't return the passed in request_queue but a normal error code, and
drop the elevator_init argument in favor of just calling elevator_init_mq
directly from dm-rq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-mq.c | 36 ++++++++++++++----------------------
block/blk.h | 1 -
block/elevator.c | 2 +-
drivers/md/dm-rq.c | 9 +++------
include/linux/blk-mq.h | 5 ++---
include/linux/elevator.h | 1 +
6 files changed, 21 insertions(+), 33 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index eaacfa963a73..6112741e1ff9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3115,21 +3115,18 @@ void blk_mq_release(struct request_queue *q)
struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
void *queuedata)
{
- struct request_queue *uninit_q, *q;
+ struct request_queue *q;
+ int ret;

- uninit_q = blk_alloc_queue(set->numa_node);
- if (!uninit_q)
+ q = blk_alloc_queue(set->numa_node);
+ if (!q)
return ERR_PTR(-ENOMEM);
- uninit_q->queuedata = queuedata;
-
- /*
- * Initialize the queue without an elevator. device_add_disk() will do
- * the initialization.
- */
- q = blk_mq_init_allocated_queue(set, uninit_q, false);
- if (IS_ERR(q))
- blk_cleanup_queue(uninit_q);
-
+ q->queuedata = queuedata;
+ ret = blk_mq_init_allocated_queue(set, q);
+ if (ret) {
+ blk_cleanup_queue(q);
+ return ERR_PTR(ret);
+ }
return q;
}
EXPORT_SYMBOL_GPL(blk_mq_init_queue_data);
@@ -3273,9 +3270,8 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
mutex_unlock(&q->sysfs_lock);
}

-struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
- struct request_queue *q,
- bool elevator_init)
+int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
+ struct request_queue *q)
{
/* mark the queue as mq asap */
q->mq_ops = set->ops;
@@ -3325,11 +3321,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
blk_mq_init_cpu_queues(q, set->nr_hw_queues);
blk_mq_add_queue_tag_set(set, q);
blk_mq_map_swqueue(q);
-
- if (elevator_init)
- elevator_init_mq(q);
-
- return q;
+ return 0;

err_hctxs:
kfree(q->queue_hw_ctx);
@@ -3340,7 +3332,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
q->poll_cb = NULL;
err_exit:
q->mq_ops = NULL;
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
}
EXPORT_SYMBOL(blk_mq_init_allocated_queue);

diff --git a/block/blk.h b/block/blk.h
index 3440142f029b..d3fa47af3607 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -192,7 +192,6 @@ void blk_account_io_done(struct request *req, u64 now);

void blk_insert_flush(struct request *rq);

-void elevator_init_mq(struct request_queue *q);
int elevator_switch_mq(struct request_queue *q,
struct elevator_type *new_e);
void __elevator_exit(struct request_queue *, struct elevator_queue *);
diff --git a/block/elevator.c b/block/elevator.c
index 440699c28119..06e203426410 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -693,7 +693,7 @@ void elevator_init_mq(struct request_queue *q)
elevator_put(e);
}
}
-
+EXPORT_SYMBOL_GPL(elevator_init_mq); /* only for dm-rq */

/*
* switch to new_e io scheduler. be careful not to introduce deadlocks -
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 9c3bc3711b33..0dbd48cbdff9 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -530,7 +530,6 @@ static const struct blk_mq_ops dm_mq_ops = {

int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
{
- struct request_queue *q;
struct dm_target *immutable_tgt;
int err;

@@ -557,12 +556,10 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
if (err)
goto out_kfree_tag_set;

- q = blk_mq_init_allocated_queue(md->tag_set, md->queue, true);
- if (IS_ERR(q)) {
- err = PTR_ERR(q);
+ err = blk_mq_init_allocated_queue(md->tag_set, md->queue);
+ if (err)
goto out_tag_set;
- }
-
+ elevator_init_mq(md->queue);
return 0;

out_tag_set:
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index bb950fc669ef..73750b2838d2 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -429,9 +429,8 @@ enum {
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
void *queuedata);
-struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
- struct request_queue *q,
- bool elevator_init);
+int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
+ struct request_queue *q);
struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
const struct blk_mq_ops *ops,
unsigned int queue_depth,
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index dcb2f9022c1d..783ecb3cb77a 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -120,6 +120,7 @@ extern void elv_merged_request(struct request_queue *, struct request *,
extern bool elv_attempt_insert_merge(struct request_queue *, struct request *);
extern struct request *elv_former_request(struct request_queue *, struct request *);
extern struct request *elv_latter_request(struct request_queue *, struct request *);
+void elevator_init_mq(struct request_queue *q);

/*
* io scheduler registration