自学教程：C++ rq_fifo_clear函数代码示例

/* * remove rq from rbtree and fifo. */static void deadline_remove_request(struct request_queue *q, struct request *rq){	struct deadline_data *dd = q->elevator->elevator_data;	rq_fifo_clear(rq);	deadline_del_rq_rb(dd, rq);}

static voidvr_add_request(struct request_queue *q, struct request *rq){struct sio_data *sd = q->elevator->elevator_data;const int sync = rq_is_sync(rq);const int data_dir = rq_data_dir(rq);/** We might be deleting our cached next request.* If so, find its sucessor.*//** add rq to rbtree and fifo*/static voidvr_add_request(struct request_queue *q, struct request *rq)struct request *next){struct vr_data *vd = vr_get_data(q);const int dir = rq_is_sync(rq);}/** If next expires before rq, assign its expire time to rq* and move into next position (next will be deleted) in fifo.*/if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) {if (time_before(rq_fifo_time(next), rq_fifo_time(rq))) {list_move(&rq->queuelist, &next->queuelist);rq_set_fifo_time(rq, rq_fifo_time(next));}}/* Delete next request */rq_fifo_clear(next);}

/*  Implement elevator_merge_fn: do nothing for now    Implement elevator_merged_fn: If larger than predefined bundle size, remove from async queue and add to tail of bundle queue; */static void flash_merged_request(struct request_queue *q,				    struct request *req, int type){	struct flash_data *fd = q->elevator->elevator_data;	// FIXME:	// const int data_type = !rq_is_sync(req);	const int data_type = rq_data_dir(req);	// BUG if req already in bundle queue	/* FIXME: how to check if a req belong to certain queue? */	// if req >= bundle_size, delete from async_fifo queue, add tail to bundle queue	#ifdef DEBUG_FLASH	printk("req is of size %d after merging/n", req->__data_len);	#endif	// only kick req into bundle queue if req is async	if(req->__data_len >= fd->bundle_size && data_type == 1)	{		/* did both delete and init */		rq_fifo_clear(req); 		list_add_tail(&req->queuelist, &fd->bundle_list);		#ifdef DEBUG_FLASH		printk("req of type %d of size %d is inserted to bundle queue/n", data_type, req->__data_len);		#endif	}}

static void zen_dispatch(struct zen_data *zdata, struct request *rq){	/* Remove request from list and dispatch it */	rq_fifo_clear(rq);	elv_dispatch_add_tail(rq->q, rq);	/* Increment # of sequential requests */	zdata->batching++;}

static inline voidsio_dispatch_request(struct sio_data *sd, struct request *rq){/** Remove the request from the fifo list* and dispatch it.*/rq_fifo_clear(rq);elv_dispatch_add_tail(rq->q, rq);sd->batched++;}

/* * move request from additional fifo list to dispatch queue. */static inline voidflash_move_to_dispatch(struct flash_data *dd, struct request *rq){	struct request_queue *q = rq->q;	/* remove rq from its associated fifo queue and reinit */	rq_fifo_clear(rq);	elv_dispatch_add_tail(q, rq);	#ifdef DEBUG_FLASH	printk("req of size %d is moved to dispatch queue/n", rq->__data_len);	#endif}

static inline void tripndroid_dispatch_request(struct tripndroid_data *td, struct request *rq){	/* Dispatch the request */	rq_fifo_clear(rq);	elv_dispatch_add_tail(rq->q, rq);	td->batched++;	if (rq_data_dir(rq))		td->starved = 0;	else		td->starved++;}

static voidsio_merged_requests(struct request_queue *q, struct request *rq,		    struct request *next){	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) {		if (time_before(rq_fifo_time(next), rq_fifo_time(rq))) {			list_move(&rq->queuelist, &next->queuelist);			rq_set_fifo_time(rq, rq_fifo_time(next));		}	}	rq_fifo_clear(next);}

static inline voidsio_dispatch_request(struct sio_data *sd, struct request *rq){	rq_fifo_clear(rq);	elv_dispatch_add_tail(rq->q, rq);	if (rq_data_dir(rq)) {		sd->starved = 0;	} else {		if (!list_empty(&sd->fifo_list[SYNC][WRITE]) || 				!list_empty(&sd->fifo_list[ASYNC][WRITE]))			sd->starved++;	}}

/*    This function does 3 tasks:   1 check if next expires before req, is so set expire time of req to be the expire time of next   2 delete next from async fifo queue   3 check if merged req size >= bundle_size; if so, delete req from async fifo queue, reinit and insert it to bundle queue */static voidflash_merged_requests(struct request_queue *q, struct request *req,			 struct request *next){	struct flash_data *fd = q->elevator->elevator_data;	// const int data_type = !rq_is_sync(req);	// FIXME:	const int data_type = rq_data_dir(req);	/*	 * if next expires before rq, assign its expire time to rq	 * and move into next position (next will be deleted) in fifo	 */	// TODO: why need to check if async queue is empty here?	if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {		if (time_before(rq_fifo_time(next), rq_fifo_time(req))) {			list_move(&req->queuelist, &next->queuelist);			rq_set_fifo_time(req, rq_fifo_time(next));		}	}	/* delete next */	rq_fifo_clear(next);		/* task 3 only kick into bundle queue if req is async */	if(req->__data_len >= fd->bundle_size && data_type == 1)	{		/* did both delete and init */		rq_fifo_clear(req); 		list_add_tail(&req->queuelist, &fd->bundle_list);				#ifdef DEBUG_FLASH		printk("req of type %d of size %d is inserted to bundle queue/n", data_type, req->__data_len);		#endif	}}

static void tripndroid_merged_requests(struct request_queue *q, struct request *rq,		    struct request *next){	/*	 * If next expires before rq, assign its expire time to rq	 * and move into next position (next will be deleted) in fifo.	 */	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) {		time_before(next->fifo_time, rq->fifo_time); {			list_move(&rq->queuelist, &next->queuelist);			rq->fifo_time = next->fifo_time;		}	}	rq_fifo_clear(next);}

static inline voidsio_dispatch_request(struct sio_data *sd, struct request *rq){	/* Remove the request from the fifo list and dispatch it. */	rq_fifo_clear(rq);	elv_dispatch_add_tail(rq->q, rq);	sd->batched++;	if (rq_data_dir(rq)) {		sd->starved = 0;	} else {		if (!list_empty(&sd->fifo_list[SYNC][WRITE]) ||				!list_empty(&sd->fifo_list[ASYNC][WRITE]))			sd->starved++;	}}

static voidsio_merged_requests(struct request_queue *q, struct request *rq,struct request *next){/** If next expires before rq, assign its expire time to rq* and move into next position (next will be deleted) in fifo.*/if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) {if (time_before(rq_fifo_time(next), rq_fifo_time(rq))) {list_move(&rq->queuelist, &next->queuelist);rq_set_fifo_time(rq, rq_fifo_time(next));}}/* Delete next request */rq_fifo_clear(next);}

void ElvDeadline::deadline_remove_request(request *rq){	rq_fifo_clear(rq);	deadline_del_rq_rb(rq);}