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-rw-r--r--block/elevator.c131
1 files changed, 46 insertions, 85 deletions
diff --git a/block/elevator.c b/block/elevator.c
index ec585c9554d..282e8308f7e 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -617,8 +617,6 @@ void elv_quiesce_end(struct request_queue *q)
void elv_insert(struct request_queue *q, struct request *rq, int where)
{
- struct list_head *pos;
- unsigned ordseq;
int unplug_it = 1;
trace_block_rq_insert(q, rq);
@@ -626,9 +624,16 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
rq->q = q;
switch (where) {
+ case ELEVATOR_INSERT_REQUEUE:
+ /*
+ * Most requeues happen because of a busy condition,
+ * don't force unplug of the queue for that case.
+ * Clear unplug_it and fall through.
+ */
+ unplug_it = 0;
+
case ELEVATOR_INSERT_FRONT:
rq->cmd_flags |= REQ_SOFTBARRIER;
-
list_add(&rq->queuelist, &q->queue_head);
break;
@@ -668,36 +673,6 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
q->elevator->ops->elevator_add_req_fn(q, rq);
break;
- case ELEVATOR_INSERT_REQUEUE:
- /*
- * If ordered flush isn't in progress, we do front
- * insertion; otherwise, requests should be requeued
- * in ordseq order.
- */
- rq->cmd_flags |= REQ_SOFTBARRIER;
-
- /*
- * Most requeues happen because of a busy condition,
- * don't force unplug of the queue for that case.
- */
- unplug_it = 0;
-
- if (q->ordseq == 0) {
- list_add(&rq->queuelist, &q->queue_head);
- break;
- }
-
- ordseq = blk_ordered_req_seq(rq);
-
- list_for_each(pos, &q->queue_head) {
- struct request *pos_rq = list_entry_rq(pos);
- if (ordseq <= blk_ordered_req_seq(pos_rq))
- break;
- }
-
- list_add_tail(&rq->queuelist, pos);
- break;
-
default:
printk(KERN_ERR "%s: bad insertion point %d\n",
__func__, where);
@@ -716,26 +691,8 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
void __elv_add_request(struct request_queue *q, struct request *rq, int where,
int plug)
{
- if (q->ordcolor)
- rq->cmd_flags |= REQ_ORDERED_COLOR;
-
if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
- /*
- * toggle ordered color
- */
- if (rq->cmd_flags & REQ_HARDBARRIER)
- q->ordcolor ^= 1;
-
- /*
- * barriers implicitly indicate back insertion
- */
- if (where == ELEVATOR_INSERT_SORT)
- where = ELEVATOR_INSERT_BACK;
-
- /*
- * this request is scheduling boundary, update
- * end_sector
- */
+ /* barriers are scheduling boundary, update end_sector */
if (rq->cmd_type == REQ_TYPE_FS ||
(rq->cmd_flags & REQ_DISCARD)) {
q->end_sector = rq_end_sector(rq);
@@ -855,24 +812,6 @@ void elv_completed_request(struct request_queue *q, struct request *rq)
e->ops->elevator_completed_req_fn)
e->ops->elevator_completed_req_fn(q, rq);
}
-
- /*
- * Check if the queue is waiting for fs requests to be
- * drained for flush sequence.
- */
- if (unlikely(q->ordseq)) {
- struct request *next = NULL;
-
- if (!list_empty(&q->queue_head))
- next = list_entry_rq(q->queue_head.next);
-
- if (!queue_in_flight(q) &&
- blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN &&
- (!next || blk_ordered_req_seq(next) > QUEUE_ORDSEQ_DRAIN)) {
- blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0);
- __blk_run_queue(q);
- }
- }
}
#define to_elv(atr) container_of((atr), struct elv_fs_entry, attr)
@@ -938,6 +877,7 @@ int elv_register_queue(struct request_queue *q)
}
}
kobject_uevent(&e->kobj, KOBJ_ADD);
+ e->registered = 1;
}
return error;
}
@@ -947,6 +887,7 @@ static void __elv_unregister_queue(struct elevator_queue *e)
{
kobject_uevent(&e->kobj, KOBJ_REMOVE);
kobject_del(&e->kobj);
+ e->registered = 0;
}
void elv_unregister_queue(struct request_queue *q)
@@ -1009,18 +950,19 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
{
struct elevator_queue *old_elevator, *e;
void *data;
+ int err;
/*
* Allocate new elevator
*/
e = elevator_alloc(q, new_e);
if (!e)
- return 0;
+ return -ENOMEM;
data = elevator_init_queue(q, e);
if (!data) {
kobject_put(&e->kobj);
- return 0;
+ return -ENOMEM;
}
/*
@@ -1041,10 +983,13 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
spin_unlock_irq(q->queue_lock);
- __elv_unregister_queue(old_elevator);
+ if (old_elevator->registered) {
+ __elv_unregister_queue(old_elevator);
- if (elv_register_queue(q))
- goto fail_register;
+ err = elv_register_queue(q);
+ if (err)
+ goto fail_register;
+ }
/*
* finally exit old elevator and turn off BYPASS.
@@ -1056,7 +1001,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name);
- return 1;
+ return 0;
fail_register:
/*
@@ -1071,17 +1016,19 @@ fail_register:
queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q);
spin_unlock_irq(q->queue_lock);
- return 0;
+ return err;
}
-ssize_t elv_iosched_store(struct request_queue *q, const char *name,
- size_t count)
+/*
+ * Switch this queue to the given IO scheduler.
+ */
+int elevator_change(struct request_queue *q, const char *name)
{
char elevator_name[ELV_NAME_MAX];
struct elevator_type *e;
if (!q->elevator)
- return count;
+ return -ENXIO;
strlcpy(elevator_name, name, sizeof(elevator_name));
e = elevator_get(strstrip(elevator_name));
@@ -1092,13 +1039,27 @@ ssize_t elv_iosched_store(struct request_queue *q, const char *name,
if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) {
elevator_put(e);
- return count;
+ return 0;
}
- if (!elevator_switch(q, e))
- printk(KERN_ERR "elevator: switch to %s failed\n",
- elevator_name);
- return count;
+ return elevator_switch(q, e);
+}
+EXPORT_SYMBOL(elevator_change);
+
+ssize_t elv_iosched_store(struct request_queue *q, const char *name,
+ size_t count)
+{
+ int ret;
+
+ if (!q->elevator)
+ return count;
+
+ ret = elevator_change(q, name);
+ if (!ret)
+ return count;
+
+ printk(KERN_ERR "elevator: switch to %s failed\n", name);
+ return ret;
}
ssize_t elv_iosched_show(struct request_queue *q, char *name)
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-26 06:36:32 +0000