gendisk can't be gone when there is IO activity, so not hold part0's refcount in IO path. Cc: Yufen Yu <yuyufen@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Hou Tao <houtao1@xxxxxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- block/blk-core.c | 3 ++- block/blk-merge.c | 3 ++- block/genhd.c | 4 ++-- 3 files changed, 6 insertions(+), 4 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/blk-merge.c b/block/blk-merge.c index a04e991b5ded..b44caa28ec04 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -672,7 +672,8 @@ static void blk_account_io_merge(struct request *req) 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 bf8cbb033d64..d97b95d1a2fd 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -345,7 +345,8 @@ static inline int sector_in_part(struct hd_struct *part, sector_t sector) * * CONTEXT: * RCU read locked. The returned partition pointer is always valid - * because its refcount is grabbed. + * because its refcount is grabbed except for part0, which lifetime + * is same with the disk. * * RETURNS: * Found partition on success, part0 is returned if no partition matches @@ -378,7 +379,6 @@ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) return part; } } - hd_struct_get(&disk->part0); return &disk->part0; } -- 2.25.2
