waterDataFluctuationCorrelation analysisOfLiquidLevelDataOperation.c 薛梅子 commit at 2021-04-09

waterDataFluctuationCorrelation/fluctuationCorrelationOfSprayEnd/analysisOfLiquidLevelDataOperation.c

@@ -241,3 +241,157 @@ int blk_queue_resize_tags(struct request_queue *q, int new_depth)
 	 * one, so error out if this is the case
 	 */
 	if (atomic_read(&bqt->refcnt) != 1)
+		return -EBUSY;
+
+	/*
+	 * save the old state info, so we can copy it back
+	 */
+	tag_index = bqt->tag_index;
+	tag_map = bqt->tag_map;
+	max_depth = bqt->real_max_depth;
+
+	if (init_tag_map(q, bqt, new_depth))
+		return -ENOMEM;
+
+	memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
+	nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
+	memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
+
+	kfree(tag_index);
+	kfree(tag_map);
+	return 0;
+}
+EXPORT_SYMBOL(blk_queue_resize_tags);
+
+/**
+ * blk_queue_end_tag - end tag operations for a request
+ * @q:  the request queue for the device
+ * @rq: the request that has completed
+ *
+ *  Description:
+ *    Typically called when end_that_request_first() returns %0, meaning
+ *    all transfers have been done for a request. It's important to call
+ *    this function before end_that_request_last(), as that will put the
+ *    request back on the free list thus corrupting the internal tag list.
+ *
+ *  Notes:
+ *   queue lock must be held.
+ **/
+void blk_queue_end_tag(struct request_queue *q, struct request *rq)
+{
+	struct blk_queue_tag *bqt = q->queue_tags;
+	unsigned tag = rq->tag; /* negative tags invalid */
+
+	BUG_ON(tag >= bqt->real_max_depth);
+
+	list_del_init(&rq->queuelist);
+	rq->cmd_flags &= ~REQ_QUEUED;
+	rq->tag = -1;
+
+	if (unlikely(bqt->tag_index[tag] == NULL))
+		printk(KERN_ERR "%s: tag %d is missing\n",
+		       __func__, tag);
+
+	bqt->tag_index[tag] = NULL;
+
+	if (unlikely(!test_bit(tag, bqt->tag_map))) {
+		printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
+		       __func__, tag);
+		return;
+	}
+	/*
+	 * The tag_map bit acts as a lock for tag_index[bit], so we need
+	 * unlock memory barrier semantics.
+	 */
+	clear_bit_unlock(tag, bqt->tag_map);
+}
+EXPORT_SYMBOL(blk_queue_end_tag);
+
+/**
+ * blk_queue_start_tag - find a free tag and assign it
+ * @q:  the request queue for the device
+ * @rq:  the block request that needs tagging
+ *
+ *  Description:
+ *    This can either be used as a stand-alone helper, or possibly be
+ *    assigned as the queue &prep_rq_fn (in which case &struct request
+ *    automagically gets a tag assigned). Note that this function
+ *    assumes that any type of request can be queued! if this is not
+ *    true for your device, you must check the request type before
+ *    calling this function.  The request will also be removed from
+ *    the request queue, so it's the drivers responsibility to readd
+ *    it if it should need to be restarted for some reason.
+ *
+ *  Notes:
+ *   queue lock must be held.
+ **/
+int blk_queue_start_tag(struct request_queue *q, struct request *rq)
+{
+	struct blk_queue_tag *bqt = q->queue_tags;
+	unsigned max_depth;
+	int tag;
+
+	if (unlikely((rq->cmd_flags & REQ_QUEUED))) {
+		printk(KERN_ERR
+		       "%s: request %p for device [%s] already tagged %d",
+		       __func__, rq,
+		       rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
+		BUG();
+	}
+
+	/*
+	 * Protect against shared tag maps, as we may not have exclusive
+	 * access to the tag map.
+	 *
+	 * We reserve a few tags just for sync IO, since we don't want
+	 * to starve sync IO on behalf of flooding async IO.
+	 */
+	max_depth = bqt->max_depth;
+	if (!rq_is_sync(rq) && max_depth > 1) {
+		max_depth -= 2;
+		if (!max_depth)
+			max_depth = 1;
+		if (q->in_flight[BLK_RW_ASYNC] > max_depth)
+			return 1;
+	}
+
+	do {
+		tag = find_first_zero_bit(bqt->tag_map, max_depth);
+		if (tag >= max_depth)
+			return 1;
+
+	} while (test_and_set_bit_lock(tag, bqt->tag_map));
+	/*
+	 * We need lock ordering semantics given by test_and_set_bit_lock.
+	 * See blk_queue_end_tag for details.
+	 */
+
+	rq->cmd_flags |= REQ_QUEUED;
+	rq->tag = tag;
+	bqt->tag_index[tag] = rq;
+	blk_start_request(rq);
+	list_add(&rq->queuelist, &q->tag_busy_list);
+	return 0;
+}
+EXPORT_SYMBOL(blk_queue_start_tag);
+
+/**
+ * blk_queue_invalidate_tags - invalidate all pending tags
+ * @q:  the request queue for the device
+ *
+ *  Description:
+ *   Hardware conditions may dictate a need to stop all pending requests.
+ *   In this case, we will safely clear the block side of the tag queue and
+ *   readd all requests to the request queue in the right order.
+ *
+ *  Notes:
+ *   queue lock must be held.
+ **/
+void blk_queue_invalidate_tags(struct request_queue *q)
+{
+	struct list_head *tmp, *n;
+
+	list_for_each_safe(tmp, n, &q->tag_busy_list)
+		blk_requeue_request(q, list_entry_rq(tmp));
+}
+EXPORT_SYMBOL(blk_queue_invalidate_tags);