[PATCH RFC V3 4/4] block: call blk_additional_{latency,sector} only when io_extra_stats is true

[Guoqing Jiang <guoqing.jiang@gmx.com>]

From: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>

If ADDITIONAL_DISKSTAT is enabled carelessly, then it is bad to people
who don't want the additional overhead.

Now add check before call blk_additional_{latency,sector}, which guarntee
only those who really know about the attribute can account the additional
data.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
---
 block/blk-core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 1a8e508516c9..eafc2b390d99 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1462,7 +1462,8 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)

 		part_stat_lock();
 		part = req->part;
-		blk_additional_sector(part, sgrp, bytes >> SECTOR_SHIFT);
+		if (blk_queue_extra_io_stat(req->q))
+			blk_additional_sector(part, sgrp, bytes >> SECTOR_SHIFT);
 		part_stat_add(part, sectors[sgrp], bytes >> 9);
 		part_stat_unlock();
 	}
@@ -1484,7 +1485,8 @@ void blk_account_io_done(struct request *req, u64 now)
 		part = req->part;

 		update_io_ticks(part, jiffies, true);
-		blk_additional_latency(part, sgrp, req, 0);
+		if (blk_queue_extra_io_stat(req->q))
+			blk_additional_latency(part, sgrp, req, 0);
 		part_stat_inc(part, ios[sgrp]);
 		part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
 		part_stat_unlock();
@@ -1516,7 +1518,8 @@ unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
 	update_io_ticks(part, now, false);
 	part_stat_inc(part, ios[sgrp]);
 	part_stat_add(part, sectors[sgrp], sectors);
-	blk_additional_sector(part, sgrp, sectors);
+	if (blk_queue_extra_io_stat(disk->queue))
+		blk_additional_sector(part, sgrp, sectors);
 	part_stat_local_inc(part, in_flight[op_is_write(op)]);
 	part_stat_unlock();

@@ -1534,7 +1537,8 @@ void disk_end_io_acct(struct gendisk *disk, unsigned int op,

 	part_stat_lock();
 	update_io_ticks(part, now, true);
-	blk_additional_latency(part, sgrp, NULL, start_time);
+	if (blk_queue_extra_io_stat(disk->queue))
+		blk_additional_latency(part, sgrp, NULL, start_time);
 	part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
 	part_stat_local_dec(part, in_flight[op_is_write(op)]);
 	part_stat_unlock();
--
2.17.1