[PATCH 4/4] block: don't hold part0's refcount in IO path

Ming Lei
2020-05-07T08:53:17Z

gendisk can't be gone when there is IO activity, so not hold
part0's refcount in IO path.

Cc: Yufen Yu <yuyufen@huawei.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hou Tao <houtao1@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-core.c | 3 ++-
block/genhd.c | 1 -
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 826a8980997d..56cc61354671 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1343,7 +1343,8 @@ void blk_account_io_done(struct request *req, u64 now)
part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
part_dec_in_flight(req->q, part, rq_data_dir(req));

- hd_struct_put(part);
+ if (part->partno)
+ hd_struct_put(part);
part_stat_unlock();
}
}
diff --git a/block/genhd.c b/block/genhd.c
index c0288b89a7ad..af8641351510 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -373,7 +373,6 @@ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
}
}
exit:
- hd_struct_get(&disk->part0);
return &disk->part0;
}

--
2.25.2