block: Stop abusing csd.list for fifo_time

Block layer currently abuses rq->csd.list.next for storing fifo_time. That is a terrible hack and completely unnecessary as well. Union achieves the same space saving in a cleaner way.

Jan Kara committed 12 years ago

Commit 8b4922d1 parent bf36f9c4 files · +9 −14Browse files

Unified · Split

4 files

block/cfq-iosched.c +4 −4
block/deadline-iosched.c +4 −4
include/linux/blkdev.h +1 −0
include/linux/elevator.h +0 −6

block/cfq-iosched.c+4−4

@@ -2367,10 +2367,10 @@ cfq_merged_requests(struct request_queue q, struct request rq, · 2366 unmodified lines
2367	* reposition in fifo if next is older than rq	2367	* reposition in fifo if next is older than rq
2368	*/	2368	*/
2369	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&	2369	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
2370	time_before(rq_fifo_time(next), rq_fifo_time(rq)) &&	2370	time_before(next->fifo_time, rq->fifo_time) &&
2371	cfqq == RQ_CFQQ(next)) {	2371	cfqq == RQ_CFQQ(next)) {
2372	list_move(&rq->queuelist, &next->queuelist);	2372	list_move(&rq->queuelist, &next->queuelist);
2373	rq_set_fifo_time(rq, rq_fifo_time(next));	2373	rq->fifo_time = next->fifo_time;
2374	}	2374	}
2375		2375
2376	if (cfqq->next_rq == next)	2376	if (cfqq->next_rq == next)
@@ -2814,7 +2814,7 @@ static struct request cfq_check_fifo(struct cfq_queue cfqq) · 437 unmodified lines
2814	return NULL;	2814	return NULL;
2815		2815
2816	rq = rq_entry_fifo(cfqq->fifo.next);	2816	rq = rq_entry_fifo(cfqq->fifo.next);
2817	if (time_before(jiffies, rq_fifo_time(rq)))	2817	if (time_before(jiffies, rq->fifo_time))
2818	rq = NULL;	2818	rq = NULL;
2819		2819
2820	cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);	2820	cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
@@ -3927,7 +3927,7 @@ static void cfq_insert_request(struct request_queue q, struct request rq) · 1106 unmodified lines
3927	cfq_log_cfqq(cfqd, cfqq, "insert_request");	3927	cfq_log_cfqq(cfqd, cfqq, "insert_request");
3928	cfq_init_prio_data(cfqq, RQ_CIC(rq));	3928	cfq_init_prio_data(cfqq, RQ_CIC(rq));
3929		3929
3930	rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);	3930	rq->fifo_time = jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)];
3931	list_add_tail(&rq->queuelist, &cfqq->fifo);	3931	list_add_tail(&rq->queuelist, &cfqq->fifo);
3932	cfq_add_rq_rb(rq);	3932	cfq_add_rq_rb(rq);
3933	cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group,	3933	cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group,

block/deadline-iosched.c+4−4

@@ -106,7 +106,7 @@ deadline_add_request(struct request_queue q, struct request rq) · 105 unmodified lines
106	/*	106	/*
107	* set expire time and add to fifo list	107	* set expire time and add to fifo list
108	*/	108	*/
109	rq_set_fifo_time(rq, jiffies + dd->fifo_expire[data_dir]);	109	rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
110	list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);	110	list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
111	}	111	}
112		112
@@ -174,9 +174,9 @@ deadline_merged_requests(struct request_queue q, struct request req, · 61 unmodified lines
174	* and move into next position (next will be deleted) in fifo	174	* and move into next position (next will be deleted) in fifo
175	*/	175	*/
176	if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {	176	if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
177	if (time_before(rq_fifo_time(next), rq_fifo_time(req))) {	177	if (time_before(next->fifo_time, req->fifo_time)) {
178	list_move(&req->queuelist, &next->queuelist);	178	list_move(&req->queuelist, &next->queuelist);
179	rq_set_fifo_time(req, rq_fifo_time(next));	179	req->fifo_time = next->fifo_time;
180	}	180	}
181	}	181	}
182		182
@@ -230,7 +230,7 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) · 47 unmodified lines
230	/*	230	/*
231	* rq is expired!	231	* rq is expired!
232	*/	232	*/
233	if (time_after_eq(jiffies, rq_fifo_time(rq)))	233	if (time_after_eq(jiffies, rq->fifo_time))
234	return 1;	234	return 1;
235		235
236	return 0;	236	return 0;

include/linux/blkdev.h+1−0

@@ -99,6 +99,7 @@ struct request { · 98 unmodified lines
99	union {	99	union {
100	struct call_single_data csd;	100	struct call_single_data csd;
101	struct work_struct mq_flush_work;	101	struct work_struct mq_flush_work;
		102	unsigned long fifo_time;
102	};	103	};
103		104
104	struct request_queue *q;	105	struct request_queue *q;

include/linux/elevator.h+0−6

 #define rq_end_sector(rq)	(blk_rq_pos(rq) + blk_rq_sectors(rq))
 #define rb_entry_rq(node)	rb_entry((node), struct request, rb_node)
-/*
- * Hack to reuse the csd.list list_head as the fifo time holder while
- * the request is in the io scheduler. Saves an unsigned long in rq.
- */
-#define rq_fifo_time(rq)	((unsigned long) (rq)->csd.list.next)
-#define rq_set_fifo_time(rq,exp)	((rq)->csd.list.next = (void *) (exp))
 #define rq_entry_fifo(ptr)	list_entry((ptr), struct request, queuelist)
 #define rq_fifo_clear(rq)	do {		\
 	list_del_init(&(rq)->queuelist);	\