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@@ -155,9 +155,10 @@ static void elevator_setup_default(void)
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/*
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* If the given scheduler is not available, fall back to no-op.
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*/
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- if (!(e = elevator_find(chosen_elevator)))
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+ if ((e = elevator_find(chosen_elevator)))
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+ elevator_put(e);
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+ else
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strcpy(chosen_elevator, "noop");
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- elevator_put(e);
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}
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static int __init elevator_setup(char *str)
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@@ -190,14 +191,14 @@ int elevator_init(request_queue_t *q, char *name)
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eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
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if (!eq) {
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- elevator_put(e->elevator_type);
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+ elevator_put(e);
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return -ENOMEM;
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}
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ret = elevator_attach(q, e, eq);
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if (ret) {
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kfree(eq);
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- elevator_put(e->elevator_type);
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+ elevator_put(e);
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}
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return ret;
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@@ -225,6 +226,7 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq)
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if (q->last_merge == rq)
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q->last_merge = NULL;
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+ q->nr_sorted--;
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boundary = q->end_sector;
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@@ -283,6 +285,7 @@ void elv_merge_requests(request_queue_t *q, struct request *rq,
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if (e->ops->elevator_merge_req_fn)
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e->ops->elevator_merge_req_fn(q, rq, next);
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+ q->nr_sorted--;
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q->last_merge = rq;
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}
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@@ -314,6 +317,20 @@ void elv_requeue_request(request_queue_t *q, struct request *rq)
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__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0);
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}
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+static void elv_drain_elevator(request_queue_t *q)
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+{
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+ static int printed;
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+ while (q->elevator->ops->elevator_dispatch_fn(q, 1))
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+ ;
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+ if (q->nr_sorted == 0)
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+ return;
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+ if (printed++ < 10) {
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+ printk(KERN_ERR "%s: forced dispatching is broken "
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+ "(nr_sorted=%u), please report this\n",
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+ q->elevator->elevator_type->elevator_name, q->nr_sorted);
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+ }
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+}
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+
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void __elv_add_request(request_queue_t *q, struct request *rq, int where,
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int plug)
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{
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@@ -348,9 +365,7 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where,
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case ELEVATOR_INSERT_BACK:
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rq->flags |= REQ_SOFTBARRIER;
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-
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- while (q->elevator->ops->elevator_dispatch_fn(q, 1))
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- ;
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+ elv_drain_elevator(q);
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list_add_tail(&rq->queuelist, &q->queue_head);
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/*
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* We kick the queue here for the following reasons.
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@@ -369,6 +384,7 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where,
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case ELEVATOR_INSERT_SORT:
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BUG_ON(!blk_fs_request(rq));
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rq->flags |= REQ_SORTED;
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+ q->nr_sorted++;
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if (q->last_merge == NULL && rq_mergeable(rq))
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q->last_merge = rq;
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/*
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@@ -525,33 +541,19 @@ int elv_queue_empty(request_queue_t *q)
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struct request *elv_latter_request(request_queue_t *q, struct request *rq)
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{
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- struct list_head *next;
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-
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elevator_t *e = q->elevator;
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if (e->ops->elevator_latter_req_fn)
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return e->ops->elevator_latter_req_fn(q, rq);
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-
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- next = rq->queuelist.next;
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- if (next != &q->queue_head && next != &rq->queuelist)
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- return list_entry_rq(next);
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-
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return NULL;
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}
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struct request *elv_former_request(request_queue_t *q, struct request *rq)
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{
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- struct list_head *prev;
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-
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elevator_t *e = q->elevator;
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if (e->ops->elevator_former_req_fn)
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return e->ops->elevator_former_req_fn(q, rq);
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-
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- prev = rq->queuelist.prev;
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- if (prev != &q->queue_head && prev != &rq->queuelist)
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- return list_entry_rq(prev);
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-
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return NULL;
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}
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@@ -691,13 +693,15 @@ static void elevator_switch(request_queue_t *q, struct elevator_type *new_e)
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set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
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- while (q->elevator->ops->elevator_dispatch_fn(q, 1))
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- ;
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+ elv_drain_elevator(q);
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while (q->rq.elvpriv) {
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+ blk_remove_plug(q);
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+ q->request_fn(q);
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spin_unlock_irq(q->queue_lock);
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msleep(10);
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spin_lock_irq(q->queue_lock);
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+ elv_drain_elevator(q);
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}
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spin_unlock_irq(q->queue_lock);
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@@ -744,13 +748,15 @@ error:
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ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count)
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{
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char elevator_name[ELV_NAME_MAX];
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+ size_t len;
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struct elevator_type *e;
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- memset(elevator_name, 0, sizeof(elevator_name));
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- strncpy(elevator_name, name, sizeof(elevator_name));
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+ elevator_name[sizeof(elevator_name) - 1] = '\0';
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+ strncpy(elevator_name, name, sizeof(elevator_name) - 1);
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+ len = strlen(elevator_name);
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- if (elevator_name[strlen(elevator_name) - 1] == '\n')
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- elevator_name[strlen(elevator_name) - 1] = '\0';
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+ if (len && elevator_name[len - 1] == '\n')
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+ elevator_name[len - 1] = '\0';
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e = elevator_get(elevator_name);
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if (!e) {
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