block, nvme: export and use passthrough stats

block/blk-mq.c

@@ -1088,36 +1088,6 @@ static inline void blk_account_io_done(struct request *req, u64 now)
 	}
 }
 
-static inline bool blk_rq_passthrough_stats(struct request *req)
-{
-	struct bio *bio = req->bio;
-
-	if (!blk_queue_passthrough_stat(req->q))
-		return false;
-
-	/* Requests without a bio do not transfer data. */
-	if (!bio)
-		return false;
-
-	/*
-	 * Stats are accumulated in the bdev, so must have one attached to a
-	 * bio to track stats. Most drivers do not set the bdev for passthrough
-	 * requests, but nvme is one that will set it.
-	 */
-	if (!bio->bi_bdev)
-		return false;
-
-	/*
-	 * We don't know what a passthrough command does, but we know the
-	 * payload size and data direction. Ensuring the size is aligned to the
-	 * block size filters out most commands with payloads that don't
-	 * represent sector access.
-	 */
-	if (blk_rq_bytes(req) & (bdev_logical_block_size(bio->bi_bdev) - 1))
-		return false;
-	return true;
-}
-
 static inline void blk_account_io_start(struct request *req)
 {
 	trace_block_io_start(req);

drivers/nvme/host/multipath.c

@@ -175,9 +175,11 @@ void nvme_mpath_start_request(struct request *rq)
 		nvme_req(rq)->flags |= NVME_MPATH_CNT_ACTIVE;
 	}
 
-	if (!blk_queue_io_stat(disk->queue) || blk_rq_is_passthrough(rq) ||
+	if (!blk_queue_io_stat(disk->queue) ||
 	    (nvme_req(rq)->flags & NVME_MPATH_IO_STATS))
 		return;
+	if (blk_rq_is_passthrough(rq) && !blk_rq_passthrough_stats(rq))
+		return;
 
 	nvme_req(rq)->flags |= NVME_MPATH_IO_STATS;
 	nvme_req(rq)->start_time = bdev_start_io_acct(disk->part0, req_op(rq),

include/linux/blk-mq.h

@@ -1243,4 +1243,33 @@ static inline int blk_rq_map_sg(struct request *rq, struct scatterlist *sglist)
 }
 void blk_dump_rq_flags(struct request *, char *);
 
+static inline bool blk_rq_passthrough_stats(struct request *req)
+{
+	struct bio *bio = req->bio;
+
+	if (!blk_queue_passthrough_stat(req->q))
+		return false;
+
+	/* Requests without a bio do not transfer data. */
+	if (!bio)
+		return false;
+
+	/*
+	 * Stats are accumulated in the bdev, so must have one attached to a
+	 * bio to track stats. Most drivers do not set the bdev for passthrough
+	 * requests, but nvme is one that will set it.
+	 */
+	if (!bio->bi_bdev)
+		return false;
+
+	/*
+	 * We don't know what a passthrough command does, but we know the
+	 * payload size and data direction. Ensuring the size is aligned to the
+	 * block size filters out most commands with payloads that don't
+	 * represent sector access.
+	 */
+	if (blk_rq_bytes(req) & (bdev_logical_block_size(bio->bi_bdev) - 1))
+		return false;
+	return true;
+}
 #endif /* BLK_MQ_H */