1 files changed, 3 insertions, 136 deletions

diff --git a/block/as-iosched.c b/block/as-iosched.c
index ad1cc4077819..6db494333c3a 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -14,7 +14,6 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/compiler.h>
-#include <linux/hash.h>
 #include <linux/rbtree.h>
 #include <linux/interrupt.h>
 
@@ -95,7 +94,6 @@ struct as_data {
 
         struct as_rq *next_arq[2];      /* next in sort order */
         sector_t last_sector[2];        /* last REQ_SYNC & REQ_ASYNC sectors */
-        struct hlist_head *hash;        /* request hash */
 
         unsigned long exit_prob;        /* probability a task will exit while
                                            being waited on */
@@ -162,11 +160,6 @@ struct as_rq {
         struct io_context *io_context;  /* The submitting task */
 
         /*
-         * request hash, key is the ending offset (for back merge lookup)
-         */
-        struct hlist_node hash;
-
-        /*
          * expire fifo
          */
         struct list_head fifo;
@@ -273,77 +266,6 @@ static void as_put_io_context(struct as_rq *arq)
 }
 
 /*
- * the back merge hash support functions
- */
-static const int as_hash_shift = 6;
-#define AS_HASH_BLOCK(sec)      ((sec) >> 3)
-#define AS_HASH_FN(sec)         (hash_long(AS_HASH_BLOCK((sec)), as_hash_shift))
-#define AS_HASH_ENTRIES         (1 << as_hash_shift)
-#define rq_hash_key(rq)         ((rq)->sector + (rq)->nr_sectors)
-
-static inline void __as_del_arq_hash(struct as_rq *arq)
-{
-        hlist_del_init(&arq->hash);
-}
-
-static inline void as_del_arq_hash(struct as_rq *arq)
-{
-        if (!hlist_unhashed(&arq->hash))
-                __as_del_arq_hash(arq);
-}
-
-static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
-{
-        struct request *rq = arq->request;
-
-        BUG_ON(!hlist_unhashed(&arq->hash));
-
-        hlist_add_head(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
-}
-
-/*
- * move hot entry to front of chain
- */
-static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq)
-{
-        struct request *rq = arq->request;
-        struct hlist_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];
-
-        if (hlist_unhashed(&arq->hash)) {
-                WARN_ON(1);
-                return;
-        }
-
-        if (&arq->hash != head->first) {
-                hlist_del(&arq->hash);
-                hlist_add_head(&arq->hash, head);
-        }
-}
-
-static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
-{
-        struct hlist_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
-        struct hlist_node *entry, *next;
-        struct as_rq *arq;
-
-        hlist_for_each_entry_safe(arq, entry, next, hash_list, hash) {
-                struct request *__rq = arq->request;
-
-                BUG_ON(hlist_unhashed(&arq->hash));
-
-                if (!rq_mergeable(__rq)) {
-                        as_del_arq_hash(arq);
-                        continue;
-                }
-
-                if (rq_hash_key(__rq) == offset)
-                        return __rq;
-        }
-
-        return NULL;
-}
-
-/*
  * rb tree support functions
  */
 #define rb_entry_arq(node)      rb_entry((node), struct as_rq, rb_node)
@@ -1060,7 +982,6 @@ static void as_remove_queued_request(request_queue_t *q, struct request *rq)
                 ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
 
         list_del_init(&arq->fifo);
-        as_del_arq_hash(arq);
         as_del_arq_rb(ad, arq);
 }
 
@@ -1349,8 +1270,6 @@ static void as_add_request(request_queue_t *q, struct request *rq)
         }
 
         as_add_arq_rb(ad, arq);
-        if (rq_mergeable(arq->request))
-                as_add_arq_hash(ad, arq);
 
         /*
          * set expire time (only used for reads) and add to fifo list
@@ -1428,42 +1347,17 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
         struct as_data *ad = q->elevator->elevator_data;
         sector_t rb_key = bio->bi_sector + bio_sectors(bio);
         struct request *__rq;
-        int ret;
-
-        /*
-         * see if the merge hash can satisfy a back merge
-         */
-        __rq = as_find_arq_hash(ad, bio->bi_sector);
-        if (__rq) {
-                BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);
-
-                if (elv_rq_merge_ok(__rq, bio)) {
-                        ret = ELEVATOR_BACK_MERGE;
-                        goto out;
-                }
-        }
 
         /*
          * check for front merge
          */
         __rq = as_find_arq_rb(ad, rb_key, bio_data_dir(bio));
-        if (__rq) {
-                BUG_ON(rb_key != rq_rb_key(__rq));
-
-                if (elv_rq_merge_ok(__rq, bio)) {
-                        ret = ELEVATOR_FRONT_MERGE;
-                        goto out;
-                }
+        if (__rq && elv_rq_merge_ok(__rq, bio)) {
+                *req = __rq;
+                return ELEVATOR_FRONT_MERGE;
         }
 
         return ELEVATOR_NO_MERGE;
-out:
-        if (ret) {
-                if (rq_mergeable(__rq))
-                        as_hot_arq_hash(ad, RQ_DATA(__rq));
-        }
-        *req = __rq;
-        return ret;
 }
 
 static void as_merged_request(request_queue_t *q, struct request *req)
@@ -1472,12 +1366,6 @@ static void as_merged_request(request_queue_t *q, struct request *req)
         struct as_rq *arq = RQ_DATA(req);
 
         /*
-         * hash always needs to be repositioned, key is end sector
-         */
-        as_del_arq_hash(arq);
-        as_add_arq_hash(ad, arq);
-
-        /*
          * if the merge was a front merge, we need to reposition request
          */
         if (rq_rb_key(req) != arq->rb_key) {
@@ -1501,13 +1389,6 @@ static void as_merged_requests(request_queue_t *q, struct request *req,
         BUG_ON(!arq);
         BUG_ON(!anext);
 
-        /*
-         * reposition arq (this is the merged request) in hash, and in rbtree
-         * in case of a front merge
-         */
-        as_del_arq_hash(arq);
-        as_add_arq_hash(ad, arq);
-
         if (rq_rb_key(req) != arq->rb_key) {
                 as_del_arq_rb(ad, arq);
                 as_add_arq_rb(ad, arq);
@@ -1591,7 +1472,6 @@ static int as_set_request(request_queue_t *q, struct request *rq,
                 arq->request = rq;
                 arq->state = AS_RQ_PRESCHED;
                 arq->io_context = NULL;
-                INIT_HLIST_NODE(&arq->hash);
                 INIT_LIST_HEAD(&arq->fifo);
                 rq->elevator_private = arq;
                 return 0;
@@ -1628,7 +1508,6 @@ static void as_exit_queue(elevator_t *e)
 
         mempool_destroy(ad->arq_pool);
         put_io_context(ad->io_context);
-        kfree(ad->hash);
         kfree(ad);
 }
 
@@ -1639,7 +1518,6 @@ static void as_exit_queue(elevator_t *e)
 static void *as_init_queue(request_queue_t *q, elevator_t *e)
 {
         struct as_data *ad;
-        int i;
 
         if (!arq_pool)
                 return NULL;
@@ -1651,17 +1529,9 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e)
 
         ad->q = q; /* Identify what queue the data belongs to */
 
-        ad->hash = kmalloc_node(sizeof(struct hlist_head)*AS_HASH_ENTRIES,
-                                GFP_KERNEL, q->node);
-        if (!ad->hash) {
-                kfree(ad);
-                return NULL;
-        }
-
         ad->arq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
                                 mempool_free_slab, arq_pool, q->node);
         if (!ad->arq_pool) {
-                kfree(ad->hash);
                 kfree(ad);
                 return NULL;
         }
@@ -1672,9 +1542,6 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e)
         init_timer(&ad->antic_timer);
         INIT_WORK(&ad->antic_work, as_work_handler, q);
 
-        for (i = 0; i < AS_HASH_ENTRIES; i++)
-                INIT_HLIST_HEAD(&ad->hash[i]);
-
         INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]);
         INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
         ad->sort_list[REQ_SYNC] = RB_ROOT;