[PATCH v2] blk-mq: Properly init requests from blk_mq_alloc_request_hctx()

[John Garry <john.garry@huawei.com>]

Function blk_mq_alloc_request_hctx() is missing zeroing/init of rq->bio,
biotail, __sector, and __data_len members, which blk_mq_alloc_request()
has, so duplicate what we do in blk_mq_alloc_request().

Fixes: 1f5bd336b9150 ("blk-mq: add blk_mq_alloc_request_hctx")
Signed-off-by: John Garry <john.garry@huawei.com>
---
Difference to v1:
- init rq members in blk_mq_alloc_request_hctx(), rather than
  blk_mq_rq_ctx_init() (Ming Lei)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 497c413bce80..a1b6afe43913 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -611,6 +611,7 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
 		.nr_tags	= 1,
 	};
 	u64 alloc_time_ns = 0;
+	struct request *rq;
 	unsigned int cpu;
 	unsigned int tag;
 	int ret;
@@ -660,8 +661,12 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
 	tag = blk_mq_get_tag(&data);
 	if (tag == BLK_MQ_NO_TAG)
 		goto out_queue_exit;
-	return blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag,
+	rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag,
 					alloc_time_ns);
+	rq->__data_len = 0;
+	rq->__sector = (sector_t) -1;
+	rq->bio = rq->biotail = NULL;
+	return rq;
 
 out_queue_exit:
 	blk_queue_exit(q);
-- 
2.25.1