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-rw-r--r--block/mq-deadline.c89
1 files changed, 86 insertions, 3 deletions
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 8bd6db9..d56972e 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -59,6 +59,7 @@ struct deadline_data {
int front_merges;
spinlock_t lock;
+ spinlock_t zone_lock;
struct list_head dispatch;
};
@@ -198,13 +199,33 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
static struct request *
deadline_fifo_request(struct deadline_data *dd, int data_dir)
{
+ struct request *rq;
+ unsigned long flags;
+
if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
return NULL;
if (list_empty(&dd->fifo_list[data_dir]))
return NULL;
- return rq_entry_fifo(dd->fifo_list[data_dir].next);
+ rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
+ if (data_dir == READ || !blk_queue_is_zoned(rq->q))
+ return rq;
+
+ /*
+ * Look for a write request that can be dispatched, that is one with
+ * an unlocked target zone.
+ */
+ spin_lock_irqsave(&dd->zone_lock, flags);
+ list_for_each_entry(rq, &dd->fifo_list[WRITE], queuelist) {
+ if (blk_req_can_dispatch_to_zone(rq))
+ goto out;
+ }
+ rq = NULL;
+out:
+ spin_unlock_irqrestore(&dd->zone_lock, flags);
+
+ return rq;
}
/*
@@ -214,10 +235,32 @@ deadline_fifo_request(struct deadline_data *dd, int data_dir)
static struct request *
deadline_next_request(struct deadline_data *dd, int data_dir)
{
+ struct request *rq;
+ unsigned long flags;
+
if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
return NULL;
- return dd->next_rq[data_dir];
+ rq = dd->next_rq[data_dir];
+ if (!rq)
+ return NULL;
+
+ if (data_dir == READ || !blk_queue_is_zoned(rq->q))
+ return rq;
+
+ /*
+ * Look for a write request that can be dispatched, that is one with
+ * an unlocked target zone.
+ */
+ spin_lock_irqsave(&dd->zone_lock, flags);
+ while (rq) {
+ if (blk_req_can_dispatch_to_zone(rq))
+ break;
+ rq = deadline_latter_request(rq);
+ }
+ spin_unlock_irqrestore(&dd->zone_lock, flags);
+
+ return rq;
}
/*
@@ -259,7 +302,8 @@ static struct request *__dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
if (reads) {
BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));
- if (writes && (dd->starved++ >= dd->writes_starved))
+ if (deadline_fifo_request(dd, WRITE) &&
+ (dd->starved++ >= dd->writes_starved))
goto dispatch_writes;
data_dir = READ;
@@ -304,6 +348,13 @@ dispatch_find_request:
rq = next_rq;
}
+ /*
+ * For a zoned block device, if we only have writes queued and none of
+ * them can be dispatched, rq will be NULL.
+ */
+ if (!rq)
+ return NULL;
+
dd->batching = 0;
dispatch_request:
@@ -313,6 +364,10 @@ dispatch_request:
dd->batching++;
deadline_move_request(dd, rq);
done:
+ /*
+ * If the request needs its target zone locked, do it.
+ */
+ blk_req_zone_write_lock(rq);
rq->rq_flags |= RQF_STARTED;
return rq;
}
@@ -368,6 +423,7 @@ static int dd_init_queue(struct request_queue *q, struct elevator_type *e)
dd->front_merges = 1;
dd->fifo_batch = fifo_batch;
spin_lock_init(&dd->lock);
+ spin_lock_init(&dd->zone_lock);
INIT_LIST_HEAD(&dd->dispatch);
q->elevator = eq;
@@ -424,6 +480,12 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
struct deadline_data *dd = q->elevator->elevator_data;
const int data_dir = rq_data_dir(rq);
+ /*
+ * This may be a requeue of a write request that has locked its
+ * target zone. If it is the case, this releases the zone lock.
+ */
+ blk_req_zone_write_unlock(rq);
+
if (blk_mq_sched_try_insert_merge(q, rq))
return;
@@ -468,6 +530,26 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
spin_unlock(&dd->lock);
}
+/*
+ * For zoned block devices, write unlock the target zone of
+ * completed write requests. Do this while holding the zone lock
+ * spinlock so that the zone is never unlocked while deadline_fifo_request()
+ * while deadline_next_request() are executing.
+ */
+static void dd_completed_request(struct request *rq)
+{
+ struct request_queue *q = rq->q;
+
+ if (blk_queue_is_zoned(q)) {
+ struct deadline_data *dd = q->elevator->elevator_data;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dd->zone_lock, flags);
+ blk_req_zone_write_unlock(rq);
+ spin_unlock_irqrestore(&dd->zone_lock, flags);
+ }
+}
+
static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
{
struct deadline_data *dd = hctx->queue->elevator->elevator_data;
@@ -669,6 +751,7 @@ static struct elevator_type mq_deadline = {
.ops.mq = {
.insert_requests = dd_insert_requests,
.dispatch_request = dd_dispatch_request,
+ .completed_request = dd_completed_request,
.next_request = elv_rb_latter_request,
.former_request = elv_rb_former_request,
.bio_merge = dd_bio_merge,