block: Expose stacked device queues in sysfs

Currently stacking devices do not have a queue directory in sysfs. However, many of the I/O characteristics like sector size, maximum request size, etc. are queue properties. This patch enables the queue directory for MD/DM devices. The elevator code has been modified to deal with queues that do not have an I/O scheduler. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: Expose stacked device queues in sysfs
Currently stacking devices do not have a queue directory in sysfs. However, many of the I/O characteristics like sector size, maximum request size, etc. are queue properties. This patch enables the queue directory for MD/DM devices. The elevator code has been modified to deal with queues that do not have an I/O scheduler. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Martin K. Petersen · Jens Axboe
1 parent 025146e13b
Showing 2 changed files with 15 additions and 4 deletions Side-by-side Diff
block/blk-sysfs.c
block/elevator.c
@@ -395,15 +395,15 @@
 	if (WARN_ON(!q))
 		return -ENXIO;
  
-	if (!q->request_fn)
-		return 0;
-
 	ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
 			  "%s", "queue");
 	if (ret < 0)
 		return ret;
  
 	kobject_uevent(&q->kobj, KOBJ_ADD);
+
+	if (!q->request_fn)
+		return 0;
  
 	ret = elv_register_queue(q);
 	if (ret) {
@@ -575,6 +575,9 @@
  */
 void elv_quiesce_start(struct request_queue *q)
 {
+	if (!q->elevator)
+		return;
+
 	queue_flag_set(QUEUE_FLAG_ELVSWITCH, q);
  
 	/*
@@ -1050,6 +1053,9 @@
 	char elevator_name[ELV_NAME_MAX];
 	struct elevator_type *e;
  
+	if (!q->elevator)
+		return count;
+
 	strlcpy(elevator_name, name, sizeof(elevator_name));
 	strstrip(elevator_name);
  
  
@@ -1073,9 +1079,14 @@
 ssize_t elv_iosched_show(struct request_queue *q, char *name)
 {
 	struct elevator_queue *e = q->elevator;
-	struct elevator_type *elv = e->elevator_type;
+	struct elevator_type *elv;
 	struct elevator_type *__e;
 	int len = 0;
+
+	if (!q->elevator)
+		return sprintf(name, "none\n");
+
+	elv = e->elevator_type;
  
 	spin_lock(&elv_list_lock);
 	list_for_each_entry(__e, &elv_list, list) {
...	...	@@ -395,15 +395,15 @@
395	395	if (WARN_ON(!q))
396	396	return -ENXIO;
397	397
398		- if (!q->request_fn)
399		- return 0;
400		-
401	398	ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
402	399	"%s", "queue");
403	400	if (ret < 0)
404	401	return ret;
405	402
406	403	kobject_uevent(&q->kobj, KOBJ_ADD);
	404	+
	405	+ if (!q->request_fn)
	406	+ return 0;
407	407
408	408	ret = elv_register_queue(q);
409	409	if (ret) {
...	...	@@ -575,6 +575,9 @@
575	575	*/
576	576	void elv_quiesce_start(struct request_queue *q)
577	577	{
	578	+ if (!q->elevator)
	579	+ return;
	580	+
578	581	queue_flag_set(QUEUE_FLAG_ELVSWITCH, q);
579	582
580	583	/*
...	...	@@ -1050,6 +1053,9 @@
1050	1053	char elevator_name[ELV_NAME_MAX];
1051	1054	struct elevator_type *e;
1052	1055
	1056	+ if (!q->elevator)
	1057	+ return count;
	1058	+
1053	1059	strlcpy(elevator_name, name, sizeof(elevator_name));
1054	1060	strstrip(elevator_name);
1055	1061
1056	1062
...	...	@@ -1073,9 +1079,14 @@
1073	1079	ssize_t elv_iosched_show(struct request_queue q, char name)
1074	1080	{
1075	1081	struct elevator_queue *e = q->elevator;
1076		- struct elevator_type *elv = e->elevator_type;
	1082	+ struct elevator_type *elv;
1077	1083	struct elevator_type *__e;
1078	1084	int len = 0;
	1085	+
	1086	+ if (!q->elevator)
	1087	+ return sprintf(name, "none\n");
	1088	+
	1089	+ elv = e->elevator_type;
1079	1090
1080	1091	spin_lock(&elv_list_lock);
1081	1092	list_for_each_entry(__e, &elv_list, list) {