waterDataFluctuationCorrelation preliminaryDataProcessing.c 张婷 commit at 2021-01-04

waterDataFluctuationCorrelation/monitoringDataProcessing/preliminaryDataProcessing.c

@@ -1318,3 +1318,166 @@ EXPORT_SYMBOL(blk_put_request);
  * a block driver.  The driver needs to take care of freeing the payload
  * itself.
  *
+ * Note that this is a quite horrible hack and nothing but handling of
+ * discard requests should ever use it.
+ */
+void blk_add_request_payload(struct request *rq, struct page *page,
+		unsigned int len)
+{
+	struct bio *bio = rq->bio;
+
+	bio->bi_io_vec->bv_page = page;
+	bio->bi_io_vec->bv_offset = 0;
+	bio->bi_io_vec->bv_len = len;
+
+	bio->bi_size = len;
+	bio->bi_vcnt = 1;
+	bio->bi_phys_segments = 1;
+
+	rq->__data_len = rq->resid_len = len;
+	rq->nr_phys_segments = 1;
+	rq->buffer = bio_data(bio);
+}
+EXPORT_SYMBOL_GPL(blk_add_request_payload);
+
+static bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
+				   struct bio *bio)
+{
+	const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
+
+	if (!ll_back_merge_fn(q, req, bio))
+		return false;
+
+	trace_block_bio_backmerge(q, bio);
+
+	if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
+		blk_rq_set_mixed_merge(req);
+
+	req->biotail->bi_next = bio;
+	req->biotail = bio;
+	req->__data_len += bio->bi_size;
+	req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
+
+	drive_stat_acct(req, 0);
+	return true;
+}
+
+static bool bio_attempt_front_merge(struct request_queue *q,
+				    struct request *req, struct bio *bio)
+{
+	const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
+
+	if (!ll_front_merge_fn(q, req, bio))
+		return false;
+
+	trace_block_bio_frontmerge(q, bio);
+
+	if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
+		blk_rq_set_mixed_merge(req);
+
+	bio->bi_next = req->bio;
+	req->bio = bio;
+
+	/*
+	 * may not be valid. if the low level driver said
+	 * it didn't need a bounce buffer then it better
+	 * not touch req->buffer either...
+	 */
+	req->buffer = bio_data(bio);
+	req->__sector = bio->bi_sector;
+	req->__data_len += bio->bi_size;
+	req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
+
+	drive_stat_acct(req, 0);
+	return true;
+}
+
+/**
+ * attempt_plug_merge - try to merge with %current's plugged list
+ * @q: request_queue new bio is being queued at
+ * @bio: new bio being queued
+ * @request_count: out parameter for number of traversed plugged requests
+ *
+ * Determine whether @bio being queued on @q can be merged with a request
+ * on %current's plugged list.  Returns %true if merge was successful,
+ * otherwise %false.
+ *
+ * Plugging coalesces IOs from the same issuer for the same purpose without
+ * going through @q->queue_lock.  As such it's more of an issuing mechanism
+ * than scheduling, and the request, while may have elvpriv data, is not
+ * added on the elevator at this point.  In addition, we don't have
+ * reliable access to the elevator outside queue lock.  Only check basic
+ * merging parameters without querying the elevator.
+ */
+static bool attempt_plug_merge(struct request_queue *q, struct bio *bio,
+			       unsigned int *request_count)
+{
+	struct blk_plug *plug;
+	struct request *rq;
+	bool ret = false;
+
+	plug = current->plug;
+	if (!plug)
+		goto out;
+	*request_count = 0;
+
+	list_for_each_entry_reverse(rq, &plug->list, queuelist) {
+		int el_ret;
+
+		if (rq->q == q)
+			(*request_count)++;
+
+		if (rq->q != q || !blk_rq_merge_ok(rq, bio))
+			continue;
+
+		el_ret = blk_try_merge(rq, bio);
+		if (el_ret == ELEVATOR_BACK_MERGE) {
+			ret = bio_attempt_back_merge(q, rq, bio);
+			if (ret)
+				break;
+		} else if (el_ret == ELEVATOR_FRONT_MERGE) {
+			ret = bio_attempt_front_merge(q, rq, bio);
+			if (ret)
+				break;
+		}
+	}
+out:
+	return ret;
+}
+
+void init_request_from_bio(struct request *req, struct bio *bio)
+{
+	req->cmd_type = REQ_TYPE_FS;
+
+	req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK;
+	if (bio->bi_rw & REQ_RAHEAD)
+		req->cmd_flags |= REQ_FAILFAST_MASK;
+
+	req->errors = 0;
+	req->__sector = bio->bi_sector;
+	req->ioprio = bio_prio(bio);
+	blk_rq_bio_prep(req->q, req, bio);
+}
+
+void blk_queue_bio(struct request_queue *q, struct bio *bio)
+{
+	const bool sync = !!(bio->bi_rw & REQ_SYNC);
+	struct blk_plug *plug;
+	int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT;
+	struct request *req;
+	unsigned int request_count = 0;
+
+	/*
+	 * low level driver can indicate that it wants pages above a
+	 * certain limit bounced to low memory (ie for highmem, or even
+	 * ISA dma in theory)
+	 */
+	blk_queue_bounce(q, &bio);
+
+	if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
+		spin_lock_irq(q->queue_lock);
+		where = ELEVATOR_INSERT_FLUSH;
+		goto get_rq;
+	}
+
+	/*