block: inline hot paths of blk_account_io_*()

Extract hot paths of __blk_account_io_start() and
__blk_account_io_done() into inline functions, so we don't always pay
for function calls.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b0662a636bd4cc7b4f84c9d0a41efa46a688ef13.1633781740.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-core.c

@@ -1180,8 +1180,7 @@ blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *
 	if (blk_crypto_insert_cloned_request(rq))
 		return BLK_STS_IOERR;
 
-	if (blk_queue_io_stat(q))
-		blk_account_io_start(rq);
+	blk_account_io_start(rq);
 
 	/*
 	 * Since we have a scheduler attached on the top device,
@@ -1260,30 +1259,19 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 	}
 }
 
-void blk_account_io_done(struct request *req, u64 now)
+void __blk_account_io_done(struct request *req, u64 now)
 {
-	/*
-	 * Account IO completion.  flush_rq isn't accounted as a
-	 * normal IO on queueing nor completion.  Accounting the
-	 * containing request is enough.
-	 */
-	if (req->part && blk_do_io_stat(req) &&
-	    !(req->rq_flags & RQF_FLUSH_SEQ)) {
-		const int sgrp = op_stat_group(req_op(req));
+	const int sgrp = op_stat_group(req_op(req));
 
-		part_stat_lock();
-		update_io_ticks(req->part, jiffies, true);
-		part_stat_inc(req->part, ios[sgrp]);
-		part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
-		part_stat_unlock();
-	}
+	part_stat_lock();
+	update_io_ticks(req->part, jiffies, true);
+	part_stat_inc(req->part, ios[sgrp]);
+	part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
+	part_stat_unlock();
 }
 
-void blk_account_io_start(struct request *rq)
+void __blk_account_io_start(struct request *rq)
 {
-	if (!blk_do_io_stat(rq))
-		return;
-
 	/* passthrough requests can hold bios that do not have ->bi_bdev set */
 	if (rq->bio && rq->bio->bi_bdev)
 		rq->part = rq->bio->bi_bdev;

block/blk.h

@@ -221,8 +221,8 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 bool blk_bio_list_merge(struct request_queue *q, struct list_head *list,
 			struct bio *bio, unsigned int nr_segs);
 
-void blk_account_io_start(struct request *req);
-void blk_account_io_done(struct request *req, u64 now);
+void __blk_account_io_start(struct request *req);
+void __blk_account_io_done(struct request *req, u64 now);
 
 /*
  * Plug flush limits
@@ -286,7 +286,25 @@ int blk_dev_init(void);
  */
 static inline bool blk_do_io_stat(struct request *rq)
 {
-	return rq->rq_disk && (rq->rq_flags & RQF_IO_STAT);
+	return (rq->rq_flags & RQF_IO_STAT) && rq->rq_disk;
+}
+
+static inline void blk_account_io_done(struct request *req, u64 now)
+{
+	/*
+	 * Account IO completion.  flush_rq isn't accounted as a
+	 * normal IO on queueing nor completion.  Accounting the
+	 * containing request is enough.
+	 */
+	if (blk_do_io_stat(req) && req->part &&
+	    !(req->rq_flags & RQF_FLUSH_SEQ))
+		__blk_account_io_done(req, now);
+}
+
+static inline void blk_account_io_start(struct request *req)
+{
+	if (blk_do_io_stat(req))
+		__blk_account_io_start(req);
 }
 
 static inline void req_set_nomerge(struct request_queue *q, struct request *req)