[PATCH V2 05/13] block: only account passthrough IO from userspace

[Ming Lei <ming.lei@redhat.com>]

Passthrough request from userspace has one active block_device/disk
associated, so they can be accounted via rq->q->disk. For other
passthrough request, there may not be disk/block_device for the queue,
since either the queue has not a disk or the disk may be deleted
already.

Add flag of BLK_MQ_REQ_USER_IO for only accounting passthrough request
from userspace.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq.c            | 13 ++++++++++++-
 drivers/nvme/host/ioctl.c |  2 +-
 drivers/scsi/scsi_ioctl.c |  3 ++-
 include/linux/blk-mq.h    |  2 ++
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index a6d4780580fc..0d25cc5778c9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -336,6 +336,17 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 }
 EXPORT_SYMBOL(blk_rq_init);
 
+static inline bool blk_mq_io_may_account(struct blk_mq_alloc_data *data)
+{
+	if (!blk_op_is_passthrough(data->cmd_flags))
+		return true;
+
+	if (data->flags & BLK_MQ_REQ_USER_IO)
+		return true;
+
+	return false;
+}
+
 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 		struct blk_mq_tags *tags, unsigned int tag, u64 alloc_time_ns)
 {
@@ -351,7 +362,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 
 	if (data->flags & BLK_MQ_REQ_PM)
 		data->rq_flags |= RQF_PM;
-	if (blk_queue_io_stat(q))
+	if (blk_queue_io_stat(q) && blk_mq_io_may_account(data))
 		data->rq_flags |= RQF_IO_STAT;
 	rq->rq_flags = data->rq_flags;
 
diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 22314962842d..f94afc38a6e3 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -66,7 +66,7 @@ static int nvme_submit_user_cmd(struct request_queue *q,
 	void *meta = NULL;
 	int ret;
 
-	req = nvme_alloc_request(q, cmd, 0);
+	req = nvme_alloc_request(q, cmd, BLK_MQ_REQ_USER_IO);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
index e13fd380deb6..b262fe06dacc 100644
--- a/drivers/scsi/scsi_ioctl.c
+++ b/drivers/scsi/scsi_ioctl.c
@@ -440,7 +440,8 @@ static int sg_io(struct scsi_device *sdev, struct sg_io_hdr *hdr, fmode_t mode)
 
 	ret = -ENOMEM;
 	rq = scsi_alloc_request(sdev->request_queue, writing ?
-			     REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
+			     REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
+			     BLK_MQ_REQ_USER_IO);
 	if (IS_ERR(rq))
 		return PTR_ERR(rq);
 	req = scsi_req(rq);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index d319ffa59354..d2ad2ed11723 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -709,6 +709,8 @@ enum {
 	BLK_MQ_REQ_RESERVED	= (__force blk_mq_req_flags_t)(1 << 1),
 	/* set RQF_PM */
 	BLK_MQ_REQ_PM		= (__force blk_mq_req_flags_t)(1 << 2),
+	/* user IO request */
+	BLK_MQ_REQ_USER_IO	= (__force blk_mq_req_flags_t)(1 << 3),
 };
 
 struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
-- 
2.31.1