[PATCH] cfq-iosched: migrate to using the elevator rb functions

This removes the rbtree handling from CFQ.

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 41 insertions, 123 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 1b803c0c90f1..b2fd8cac2147 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -46,12 +46,6 @@ static DEFINE_SPINLOCK(cfq_exit_lock);
 
 #define RQ_DATA(rq)             (rq)->elevator_private
 
-/*
- * rb-tree defines
- */
-#define rb_entry_crq(node)      rb_entry((node), struct cfq_rq, rb_node)
-#define rq_rb_key(rq)           (rq)->sector
-
 static kmem_cache_t *crq_pool;
 static kmem_cache_t *cfq_pool;
 static kmem_cache_t *cfq_ioc_pool;
@@ -185,8 +179,6 @@ struct cfq_queue {
 };
 
 struct cfq_rq {
-        struct rb_node rb_node;
-        sector_t rb_key;
         struct request *request;
 
         struct cfq_queue *cfq_queue;
@@ -376,33 +368,27 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
  */
 static struct cfq_rq *
 cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-                  struct cfq_rq *last)
+                  struct cfq_rq *last_crq)
 {
-        struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
-        struct rb_node *rbnext, *rbprev;
-
-        if (!(rbnext = rb_next(&last->rb_node))) {
-                rbnext = rb_first(&cfqq->sort_list);
-                if (rbnext == &last->rb_node)
-                        rbnext = NULL;
-        }
+        struct request *last = last_crq->request;
+        struct rb_node *rbnext = rb_next(&last->rb_node);
+        struct rb_node *rbprev = rb_prev(&last->rb_node);
+        struct cfq_rq *next = NULL, *prev = NULL;
 
-        rbprev = rb_prev(&last->rb_node);
+        BUG_ON(RB_EMPTY_NODE(&last->rb_node));
 
         if (rbprev)
-                crq_prev = rb_entry_crq(rbprev);
-        if (rbnext)
-                crq_next = rb_entry_crq(rbnext);
-
-        return cfq_choose_req(cfqd, crq_next, crq_prev);
-}
+                prev = RQ_DATA(rb_entry_rq(rbprev));
 
-static void cfq_update_next_crq(struct cfq_rq *crq)
-{
-        struct cfq_queue *cfqq = crq->cfq_queue;
+        if (rbnext)
+                next = RQ_DATA(rb_entry_rq(rbnext));
+        else {
+                rbnext = rb_first(&cfqq->sort_list);
+                if (rbnext && rbnext != &last->rb_node)
+                        next = RQ_DATA(rb_entry_rq(rbnext));
+        }
 
-        if (cfqq->next_crq == crq)
-                cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
+        return cfq_choose_req(cfqd, next, prev);
 }
 
 static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
@@ -497,71 +483,34 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq)
         BUG_ON(!cfqq->queued[sync]);
         cfqq->queued[sync]--;
 
-        cfq_update_next_crq(crq);
-
-        rb_erase(&crq->rb_node, &cfqq->sort_list);
+        elv_rb_del(&cfqq->sort_list, crq->request);
 
         if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
                 cfq_del_cfqq_rr(cfqd, cfqq);
 }
 
-static struct cfq_rq *
-__cfq_add_crq_rb(struct cfq_rq *crq)
-{
-        struct rb_node **p = &crq->cfq_queue->sort_list.rb_node;
-        struct rb_node *parent = NULL;
-        struct cfq_rq *__crq;
-
-        while (*p) {
-                parent = *p;
-                __crq = rb_entry_crq(parent);
-
-                if (crq->rb_key < __crq->rb_key)
-                        p = &(*p)->rb_left;
-                else if (crq->rb_key > __crq->rb_key)
-                        p = &(*p)->rb_right;
-                else
-                        return __crq;
-        }
-
-        rb_link_node(&crq->rb_node, parent, p);
-        return NULL;
-}
-
 static void cfq_add_crq_rb(struct cfq_rq *crq)
 {
         struct cfq_queue *cfqq = crq->cfq_queue;
         struct cfq_data *cfqd = cfqq->cfqd;
         struct request *rq = crq->request;
-        struct cfq_rq *__alias;
+        struct request *__alias;
 
-        crq->rb_key = rq_rb_key(rq);
         cfqq->queued[cfq_crq_is_sync(crq)]++;
 
         /*
          * looks a little odd, but the first insert might return an alias.
          * if that happens, put the alias on the dispatch list
          */
-        while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
-                cfq_dispatch_insert(cfqd->queue, __alias);
-
-        rb_insert_color(&crq->rb_node, &cfqq->sort_list);
-
-        if (!cfq_cfqq_on_rr(cfqq))
-                cfq_add_cfqq_rr(cfqd, cfqq);
-
-        /*
-         * check if this request is a better next-serve candidate
-         */
-        cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
+        while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
+                cfq_dispatch_insert(cfqd->queue, RQ_DATA(__alias));
 }
 
 static inline void
 cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
 {
-        rb_erase(&crq->rb_node, &cfqq->sort_list);
+        elv_rb_del(&cfqq->sort_list, crq->request);
         cfqq->queued[cfq_crq_is_sync(crq)]--;
-
         cfq_add_crq_rb(crq);
 }
 
@@ -570,28 +519,13 @@ cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
 {
         struct task_struct *tsk = current;
         pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio));
+        sector_t sector = bio->bi_sector + bio_sectors(bio);
         struct cfq_queue *cfqq;
-        struct rb_node *n;
-        sector_t sector;
 
         cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
-        if (!cfqq)
-                goto out;
-
-        sector = bio->bi_sector + bio_sectors(bio);
-        n = cfqq->sort_list.rb_node;
-        while (n) {
-                struct cfq_rq *crq = rb_entry_crq(n);
-
-                if (sector < crq->rb_key)
-                        n = n->rb_left;
-                else if (sector > crq->rb_key)
-                        n = n->rb_right;
-                else
-                        return crq->request;
-        }
+        if (cfqq)
+                return elv_rb_find(&cfqq->sort_list, sector);
 
-out:
         return NULL;
 }
 
@@ -622,6 +556,10 @@ static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
 static void cfq_remove_request(struct request *rq)
 {
         struct cfq_rq *crq = RQ_DATA(rq);
+        struct cfq_queue *cfqq = crq->cfq_queue;
+
+        if (cfqq->next_crq == crq)
+                cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
 
         list_del_init(&rq->queuelist);
         cfq_del_crq_rb(crq);
@@ -642,14 +580,14 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
         return ELEVATOR_NO_MERGE;
 }
 
-static void cfq_merged_request(request_queue_t *q, struct request *req)
+static void cfq_merged_request(request_queue_t *q, struct request *req,
+                               int type)
 {
         struct cfq_rq *crq = RQ_DATA(req);
 
-        if (rq_rb_key(req) != crq->rb_key) {
+        if (type == ELEVATOR_FRONT_MERGE) {
                 struct cfq_queue *cfqq = crq->cfq_queue;
 
-                cfq_update_next_crq(crq);
                 cfq_reposition_crq_rb(cfqq, crq);
         }
 }
@@ -658,8 +596,6 @@ static void
 cfq_merged_requests(request_queue_t *q, struct request *rq,
                     struct request *next)
 {
-        cfq_merged_request(q, rq);
-
         /*
          * reposition in fifo if next is older than rq
          */
@@ -881,7 +817,6 @@ static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
         struct cfq_queue *cfqq = crq->cfq_queue;
         struct request *rq;
 
-        cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
         cfq_remove_request(crq->request);
         cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
         elv_dispatch_sort(q, crq->request);
@@ -1700,6 +1635,12 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         struct cfq_io_context *cic = crq->io_context;
 
         /*
+         * check if this request is a better next-serve candidate
+         */
+        cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
+        BUG_ON(!cfqq->next_crq);
+
+        /*
          * we never wait for an async request and we don't allow preemption
          * of an async request. so just return early
          */
@@ -1756,6 +1697,9 @@ static void cfq_insert_request(request_queue_t *q, struct request *rq)
 
         cfq_add_crq_rb(crq);
 
+        if (!cfq_cfqq_on_rr(cfqq))
+                cfq_add_cfqq_rr(cfqd, cfqq);
+
         list_add_tail(&rq->queuelist, &cfqq->fifo);
 
         cfq_crq_enqueued(cfqd, cfqq, crq);
@@ -1803,30 +1747,6 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
         }
 }
 
-static struct request *
-cfq_former_request(request_queue_t *q, struct request *rq)
-{
-        struct cfq_rq *crq = RQ_DATA(rq);
-        struct rb_node *rbprev = rb_prev(&crq->rb_node);
-
-        if (rbprev)
-                return rb_entry_crq(rbprev)->request;
-
-        return NULL;
-}
-
-static struct request *
-cfq_latter_request(request_queue_t *q, struct request *rq)
-{
-        struct cfq_rq *crq = RQ_DATA(rq);
-        struct rb_node *rbnext = rb_next(&crq->rb_node);
-
-        if (rbnext)
-                return rb_entry_crq(rbnext)->request;
-
-        return NULL;
-}
-
 /*
  * we temporarily boost lower priority queues if they are holding fs exclusive
  * resources. they are boosted to normal prio (CLASS_BE/4)
@@ -1982,8 +1902,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
 
         crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
         if (crq) {
-                RB_CLEAR_NODE(&crq->rb_node);
-                crq->rb_key = 0;
                 crq->request = rq;
                 crq->cfq_queue = cfqq;
                 crq->io_context = cic;
@@ -2345,8 +2263,8 @@ static struct elevator_type iosched_cfq = {
                 .elevator_deactivate_req_fn =   cfq_deactivate_request,
                 .elevator_queue_empty_fn =      cfq_queue_empty,
                 .elevator_completed_req_fn =    cfq_completed_request,
-                .elevator_former_req_fn =       cfq_former_request,
-                .elevator_latter_req_fn =       cfq_latter_request,
+                .elevator_former_req_fn =       elv_rb_former_request,
+                .elevator_latter_req_fn =       elv_rb_latter_request,
                 .elevator_set_req_fn =          cfq_set_request,
                 .elevator_put_req_fn =          cfq_put_request,
                 .elevator_may_queue_fn =        cfq_may_queue,