static inline void blk_mq_tag_set_rq(struct blk_mq_hw_ctx *hctx,
		unsigned int tag, struct request *rq)
{
	hctx->tags->rqs[tag] = rq;
}
The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.