[PATCH] cfq-iosched: fix bug in timer handling for the idle class

[powerpc.git] / block / elevator.c

diff --git a/block/elevator.c b/block/elevator.c
index db3d0d8..8768a36 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -33,6 +33,7 @@
 #include <linux/init.h>
 #include <linux/compiler.h>
 #include <linux/delay.h>
+#include <linux/blktrace_api.h>
 
 #include <asm/uaccess.h>
 
@@ -144,7 +145,7 @@ static int __init elevator_setup(char *str)
                strcpy(chosen_elevator, "anticipatory");
        else
                strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
-       return 0;
+       return 1;
 }
 
 __setup("elevator=", elevator_setup);
@@ -332,6 +333,9 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
 {
        struct list_head *pos;
        unsigned ordseq;
+       int unplug_it = 1;
+
+       blk_add_trace_rq(q, rq, BLK_TA_INSERT);
 
        rq->q = q;
 
@@ -396,6 +400,11 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
                }
 
                list_add_tail(&rq->queuelist, pos);
+               /*
+                * most requeues happen because of a busy condition, don't
+                * force unplug of the queue for that case.
+                */
+               unplug_it = 0;
                break;
 
        default:
@@ -404,7 +413,7 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
                BUG();
        }
 
-       if (blk_queue_plugged(q)) {
+       if (unplug_it && blk_queue_plugged(q)) {
                int nrq = q->rq.count[READ] + q->rq.count[WRITE]
                        - q->in_flight;
 
@@ -499,6 +508,7 @@ struct request *elv_next_request(request_queue_t *q)
                         * not be passed by new incoming requests
                         */
                        rq->flags |= REQ_STARTED;
+                       blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
                }
 
                if (!q->boundary_rq || q->boundary_rq == rq) {
@@ -724,8 +734,7 @@ void elv_unregister_queue(struct request_queue *q)
 int elv_register(struct elevator_type *e)
 {
        spin_lock_irq(&elv_list_lock);
-       if (elevator_find(e->elevator_name))
-               BUG();
+       BUG_ON(elevator_find(e->elevator_name));
        list_add_tail(&e->list, &elv_list);
        spin_unlock_irq(&elv_list_lock);
 
@@ -892,10 +901,8 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name)
 EXPORT_SYMBOL(elv_dispatch_sort);
 EXPORT_SYMBOL(elv_add_request);
 EXPORT_SYMBOL(__elv_add_request);
-EXPORT_SYMBOL(elv_requeue_request);
 EXPORT_SYMBOL(elv_next_request);
 EXPORT_SYMBOL(elv_dequeue_request);
 EXPORT_SYMBOL(elv_queue_empty);
-EXPORT_SYMBOL(elv_completed_request);
 EXPORT_SYMBOL(elevator_exit);
 EXPORT_SYMBOL(elevator_init);