7 files changed, 153 insertions, 189 deletions

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index f3b7753aac99..48d090e266fc 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -40,7 +40,7 @@ config IOSCHED_CFQ
 
 choice
         prompt "Default I/O scheduler"
-        default DEFAULT_AS
+        default DEFAULT_CFQ
         help
           Select the I/O scheduler which will be used by default for all
           block devices.
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 0c750393be4a..1ec5df466708 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -96,7 +96,7 @@ 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 list_head *hash;         /* request hash */
+        struct hlist_head *hash;        /* request hash */
 
         unsigned long exit_prob;        /* probability a task will exit while
                                            being waited on */
@@ -165,8 +165,7 @@ struct as_rq {
         /*
          * request hash, key is the ending offset (for back merge lookup)
          */
-        struct list_head hash;
-        unsigned int on_hash;
+        struct hlist_node hash;
 
         /*
          * expire fifo
@@ -282,17 +281,15 @@ static const int as_hash_shift = 6;
 #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)
-#define list_entry_hash(ptr)    list_entry((ptr), struct as_rq, hash)
 
 static inline void __as_del_arq_hash(struct as_rq *arq)
 {
-        arq->on_hash = 0;
-        list_del_init(&arq->hash);
+        hlist_del_init(&arq->hash);
 }
 
 static inline void as_del_arq_hash(struct as_rq *arq)
 {
-        if (arq->on_hash)
+        if (!hlist_unhashed(&arq->hash))
                 __as_del_arq_hash(arq);
 }
 
@@ -300,10 +297,9 @@ static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
 {
         struct request *rq = arq->request;
 
-        BUG_ON(arq->on_hash);
+        BUG_ON(!hlist_unhashed(&arq->hash));
 
-        arq->on_hash = 1;
-        list_add(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
+        hlist_add_head(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
 }
 
 /*
@@ -312,31 +308,29 @@ static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
 static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq)
 {
         struct request *rq = arq->request;
-        struct list_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];
+        struct hlist_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];
 
-        if (!arq->on_hash) {
+        if (hlist_unhashed(&arq->hash)) {
                 WARN_ON(1);
                 return;
         }
 
-        if (arq->hash.prev != head) {
-                list_del(&arq->hash);
-                list_add(&arq->hash, head);
+        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 list_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
-        struct list_head *entry, *next = hash_list->next;
+        struct hlist_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
+        struct hlist_node *entry, *next;
+        struct as_rq *arq;
 
-        while ((entry = next) != hash_list) {
-                struct as_rq *arq = list_entry_hash(entry);
+        hlist_for_each_entry_safe(arq, entry, next, hash_list, hash) {
                 struct request *__rq = arq->request;
 
-                next = entry->next;
-
-                BUG_ON(!arq->on_hash);
+                BUG_ON(hlist_unhashed(&arq->hash));
 
                 if (!rq_mergeable(__rq)) {
                         as_del_arq_hash(arq);
@@ -353,9 +347,6 @@ static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
 /*
  * rb tree support functions
  */
-#define RB_EMPTY(root)  ((root)->rb_node == NULL)
-#define ON_RB(node)     (rb_parent(node) != node)
-#define RB_CLEAR(node)  (rb_set_parent(node, node))
 #define rb_entry_arq(node)      rb_entry((node), struct as_rq, rb_node)
 #define ARQ_RB_ROOT(ad, arq)    (&(ad)->sort_list[(arq)->is_sync])
 #define rq_rb_key(rq)           (rq)->sector
@@ -424,13 +415,13 @@ static void as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
 
 static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
 {
-        if (!ON_RB(&arq->rb_node)) {
+        if (!RB_EMPTY_NODE(&arq->rb_node)) {
                 WARN_ON(1);
                 return;
         }
 
         rb_erase(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
-        RB_CLEAR(&arq->rb_node);
+        RB_CLEAR_NODE(&arq->rb_node);
 }
 
 static struct request *
@@ -551,7 +542,7 @@ static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *last)
         struct rb_node *rbprev = rb_prev(&last->rb_node);
         struct as_rq *arq_next, *arq_prev;
 
-        BUG_ON(!ON_RB(&last->rb_node));
+        BUG_ON(!RB_EMPTY_NODE(&last->rb_node));
 
         if (rbprev)
                 arq_prev = rb_entry_arq(rbprev);
@@ -1128,7 +1119,7 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
         struct request *rq = arq->request;
         const int data_dir = arq->is_sync;
 
-        BUG_ON(!ON_RB(&arq->rb_node));
+        BUG_ON(!RB_EMPTY_NODE(&arq->rb_node));
 
         as_antic_stop(ad);
         ad->antic_status = ANTIC_OFF;
@@ -1253,7 +1244,7 @@ static int as_dispatch_request(request_queue_t *q, int force)
          */
 
         if (reads) {
-                BUG_ON(RB_EMPTY(&ad->sort_list[REQ_SYNC]));
+                BUG_ON(RB_EMPTY_ROOT(&ad->sort_list[REQ_SYNC]));
 
                 if (writes && ad->batch_data_dir == REQ_SYNC)
                         /*
@@ -1277,7 +1268,7 @@ static int as_dispatch_request(request_queue_t *q, int force)
 
         if (writes) {
 dispatch_writes:
-                BUG_ON(RB_EMPTY(&ad->sort_list[REQ_ASYNC]));
+                BUG_ON(RB_EMPTY_ROOT(&ad->sort_list[REQ_ASYNC]));
 
                 if (ad->batch_data_dir == REQ_SYNC) {
                         ad->changed_batch = 1;
@@ -1345,7 +1336,7 @@ static void as_add_request(request_queue_t *q, struct request *rq)
         arq->state = AS_RQ_NEW;
 
         if (rq_data_dir(arq->request) == READ
-                        || current->flags&PF_SYNCWRITE)
+                        || (arq->request->flags & REQ_RW_SYNC))
                 arq->is_sync = 1;
         else
                 arq->is_sync = 0;
@@ -1597,12 +1588,11 @@ static int as_set_request(request_queue_t *q, struct request *rq,
 
         if (arq) {
                 memset(arq, 0, sizeof(*arq));
-                RB_CLEAR(&arq->rb_node);
+                RB_CLEAR_NODE(&arq->rb_node);
                 arq->request = rq;
                 arq->state = AS_RQ_PRESCHED;
                 arq->io_context = NULL;
-                INIT_LIST_HEAD(&arq->hash);
-                arq->on_hash = 0;
+                INIT_HLIST_NODE(&arq->hash);
                 INIT_LIST_HEAD(&arq->fifo);
                 rq->elevator_private = arq;
                 return 0;
@@ -1662,7 +1652,7 @@ 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 list_head)*AS_HASH_ENTRIES,
+        ad->hash = kmalloc_node(sizeof(struct hlist_head)*AS_HASH_ENTRIES,
                                 GFP_KERNEL, q->node);
         if (!ad->hash) {
                 kfree(ad);
@@ -1684,7 +1674,7 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e)
         INIT_WORK(&ad->antic_work, as_work_handler, q);
 
         for (i = 0; i < AS_HASH_ENTRIES; i++)
-                INIT_LIST_HEAD(&ad->hash[i]);
+                INIT_HLIST_HEAD(&ad->hash[i]);
 
         INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]);
         INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index e2e6ad0a158e..e25223e147a2 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -26,7 +26,7 @@ static const int cfq_back_penalty = 2;		/* penalty of a backwards seek */
 static const int cfq_slice_sync = HZ / 10;
 static int cfq_slice_async = HZ / 25;
 static const int cfq_slice_async_rq = 2;
-static int cfq_slice_idle = HZ / 70;
+static int cfq_slice_idle = HZ / 125;
 
 #define CFQ_IDLE_GRACE          (HZ / 10)
 #define CFQ_SLICE_SCALE         (5)
@@ -60,11 +60,6 @@ static DEFINE_SPINLOCK(cfq_exit_lock);
 /*
  * rb-tree defines
  */
-#define RB_EMPTY(node)          ((node)->rb_node == NULL)
-#define RB_CLEAR(node)          do {    \
-                memset(node, 0, sizeof(*node)); \
-} while (0)
-#define RB_CLEAR_ROOT(root)     ((root)->rb_node = NULL)
 #define rb_entry_crq(node)      rb_entry((node), struct cfq_rq, rb_node)
 #define rq_rb_key(rq)           (rq)->sector
 
@@ -123,8 +118,6 @@ struct cfq_data {
          */
         struct hlist_head *crq_hash;
 
-        unsigned int max_queued;
-
         mempool_t *crq_pool;
 
         int rq_in_driver;
@@ -279,8 +272,6 @@ static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsi
 static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);
 static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
 
-#define process_sync(tsk)       ((tsk)->flags & PF_SYNCWRITE)
-
 /*
  * lots of deadline iosched dupes, can be abstracted later...
  */
@@ -336,7 +327,7 @@ static int cfq_queue_empty(request_queue_t *q)
 
 static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
 {
-        if (rw == READ || process_sync(task))
+        if (rw == READ || rw == WRITE_SYNC)
                 return task->pid;
 
         return CFQ_KEY_ASYNC;
@@ -563,7 +554,7 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq)
 
         rb_erase(&crq->rb_node, &cfqq->sort_list);
 
-        if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
+        if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
                 cfq_del_cfqq_rr(cfqd, cfqq);
 }
 
@@ -910,13 +901,15 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
         return cfqq;
 }
 
+#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
+
 static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 
 {
         struct cfq_io_context *cic;
         unsigned long sl;
 
-        WARN_ON(!RB_EMPTY(&cfqq->sort_list));
+        WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
         WARN_ON(cfqq != cfqd->active_queue);
 
         /*
@@ -943,7 +936,7 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
          * fair distribution of slice time for a process doing back-to-back
          * seeks. so allow a little bit of time for him to submit a new rq
          */
-        if (sample_valid(cic->seek_samples) && cic->seek_mean > 131072)
+        if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
                 sl = 2;
 
         mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
@@ -954,11 +947,15 @@ static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
 {
         struct cfq_data *cfqd = q->elevator->elevator_data;
         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);
+
+        rq = list_entry(q->queue_head.prev, struct request, queuelist);
+        cfqd->last_sector = rq->sector + rq->nr_sectors;
 }
 
 /*
@@ -1040,10 +1037,12 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
          * if queue has requests, dispatch one. if not, check if
          * enough slice is left to wait for one
          */
-        if (!RB_EMPTY(&cfqq->sort_list))
+        if (!RB_EMPTY_ROOT(&cfqq->sort_list))
                 goto keep_queue;
-        else if (cfq_cfqq_class_sync(cfqq) &&
-                 time_before(now, cfqq->slice_end)) {
+        else if (cfq_cfqq_dispatched(cfqq)) {
+                cfqq = NULL;
+                goto keep_queue;
+        } else if (cfq_cfqq_class_sync(cfqq)) {
                 if (cfq_arm_slice_timer(cfqd, cfqq))
                         return NULL;
         }
@@ -1062,7 +1061,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 {
         int dispatched = 0;
 
-        BUG_ON(RB_EMPTY(&cfqq->sort_list));
+        BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
 
         do {
                 struct cfq_rq *crq;
@@ -1086,14 +1085,13 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                         cfqd->active_cic = crq->io_context;
                 }
 
-                if (RB_EMPTY(&cfqq->sort_list))
+                if (RB_EMPTY_ROOT(&cfqq->sort_list))
                         break;
 
         } while (dispatched < max_dispatch);
 
         /*
-         * if slice end isn't set yet, set it. if at least one request was
-         * sync, use the sync time slice value
+         * if slice end isn't set yet, set it.
          */
         if (!cfqq->slice_end)
                 cfq_set_prio_slice(cfqd, cfqq);
@@ -1104,7 +1102,8 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
          */
         if ((!cfq_cfqq_sync(cfqq) &&
             cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-            cfq_class_idle(cfqq))
+            cfq_class_idle(cfqq) ||
+            !cfq_cfqq_idle_window(cfqq))
                 cfq_slice_expired(cfqd, 0);
 
         return dispatched;
@@ -1113,10 +1112,11 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 static int
 cfq_forced_dispatch_cfqqs(struct list_head *list)
 {
-        int dispatched = 0;
         struct cfq_queue *cfqq, *next;
         struct cfq_rq *crq;
+        int dispatched;
 
+        dispatched = 0;
         list_for_each_entry_safe(cfqq, next, list, cfq_list) {
                 while ((crq = cfqq->next_crq)) {
                         cfq_dispatch_insert(cfqq->cfqd->queue, crq);
@@ -1124,6 +1124,7 @@ cfq_forced_dispatch_cfqqs(struct list_head *list)
                 }
                 BUG_ON(!list_empty(&cfqq->fifo));
         }
+
         return dispatched;
 }
 
@@ -1150,7 +1151,8 @@ static int
 cfq_dispatch_requests(request_queue_t *q, int force)
 {
         struct cfq_data *cfqd = q->elevator->elevator_data;
-        struct cfq_queue *cfqq;
+        struct cfq_queue *cfqq, *prev_cfqq;
+        int dispatched;
 
         if (!cfqd->busy_queues)
                 return 0;
@@ -1158,10 +1160,17 @@ cfq_dispatch_requests(request_queue_t *q, int force)
         if (unlikely(force))
                 return cfq_forced_dispatch(cfqd);
 
-        cfqq = cfq_select_queue(cfqd);
-        if (cfqq) {
+        dispatched = 0;
+        prev_cfqq = NULL;
+        while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
                 int max_dispatch;
 
+                /*
+                 * Don't repeat dispatch from the previous queue.
+                 */
+                if (prev_cfqq == cfqq)
+                        break;
+
                 cfq_clear_cfqq_must_dispatch(cfqq);
                 cfq_clear_cfqq_wait_request(cfqq);
                 del_timer(&cfqd->idle_slice_timer);
@@ -1170,10 +1179,19 @@ cfq_dispatch_requests(request_queue_t *q, int force)
                 if (cfq_class_idle(cfqq))
                         max_dispatch = 1;
 
-                return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+                dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+
+                /*
+                 * If the dispatch cfqq has idling enabled and is still
+                 * the active queue, break out.
+                 */
+                if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue)
+                        break;
+
+                prev_cfqq = cfqq;
         }
 
-        return 0;
+        return dispatched;
 }
 
 /*
@@ -1379,25 +1397,28 @@ static inline void changed_ioprio(struct cfq_io_context *cic)
 {
         struct cfq_data *cfqd = cic->key;
         struct cfq_queue *cfqq;
-        if (cfqd) {
-                spin_lock(cfqd->queue->queue_lock);
-                cfqq = cic->cfqq[ASYNC];
-                if (cfqq) {
-                        struct cfq_queue *new_cfqq;
-                        new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC,
-                                                cic->ioc->task, GFP_ATOMIC);
-                        if (new_cfqq) {
-                                cic->cfqq[ASYNC] = new_cfqq;
-                                cfq_put_queue(cfqq);
-                        }
-                }
-                cfqq = cic->cfqq[SYNC];
-                if (cfqq) {
-                        cfq_mark_cfqq_prio_changed(cfqq);
-                        cfq_init_prio_data(cfqq);
+
+        if (unlikely(!cfqd))
+                return;
+
+        spin_lock(cfqd->queue->queue_lock);
+
+        cfqq = cic->cfqq[ASYNC];
+        if (cfqq) {
+                struct cfq_queue *new_cfqq;
+                new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
+                                         GFP_ATOMIC);
+                if (new_cfqq) {
+                        cic->cfqq[ASYNC] = new_cfqq;
+                        cfq_put_queue(cfqq);
                 }
-                spin_unlock(cfqd->queue->queue_lock);
         }
+
+        cfqq = cic->cfqq[SYNC];
+        if (cfqq)
+                cfq_mark_cfqq_prio_changed(cfqq);
+
+        spin_unlock(cfqd->queue->queue_lock);
 }
 
 /*
@@ -1454,7 +1475,6 @@ retry:
 
                 INIT_HLIST_NODE(&cfqq->cfq_hash);
                 INIT_LIST_HEAD(&cfqq->cfq_list);
-                RB_CLEAR_ROOT(&cfqq->sort_list);
                 INIT_LIST_HEAD(&cfqq->fifo);
 
                 cfqq->key = key;
@@ -1466,8 +1486,7 @@ retry:
                  * set ->slice_left to allow preemption for a new process
                  */
                 cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
-                if (!cfqd->hw_tag)
-                        cfq_mark_cfqq_idle_window(cfqq);
+                cfq_mark_cfqq_idle_window(cfqq);
                 cfq_mark_cfqq_prio_changed(cfqq);
                 cfq_init_prio_data(cfqq);
         }
@@ -1658,7 +1677,8 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 {
         int enable_idle = cfq_cfqq_idle_window(cfqq);
 
-        if (!cic->ioc->task || !cfqd->cfq_slice_idle || cfqd->hw_tag)
+        if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
+            (cfqd->hw_tag && CIC_SEEKY(cic)))
                 enable_idle = 0;
         else if (sample_valid(cic->ttime_samples)) {
                 if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -1688,7 +1708,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
                 return 0;
 
         if (!cfqq)
-                return 1;
+                return 0;
 
         if (cfq_class_idle(cfqq))
                 return 1;
@@ -1720,7 +1740,7 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
                 cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
 
         cfqq->slice_end = cfqq->slice_left + jiffies;
-        __cfq_slice_expired(cfqd, cfqq, 1);
+        cfq_slice_expired(cfqd, 1);
         __cfq_set_active_queue(cfqd, cfqq);
 }
 
@@ -1745,11 +1765,7 @@ static void
 cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                  struct cfq_rq *crq)
 {
-        struct cfq_io_context *cic;
-
-        cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
-
-        cic = crq->io_context;
+        struct cfq_io_context *cic = crq->io_context;
 
         /*
          * we never wait for an async request and we don't allow preemption
@@ -1839,11 +1855,23 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
                         cfqq->service_last = now;
                         cfq_resort_rr_list(cfqq, 0);
                 }
-                cfq_schedule_dispatch(cfqd);
         }
 
-        if (cfq_crq_is_sync(crq))
+        if (sync)
                 crq->io_context->last_end_request = now;
+
+        /*
+         * If this is the active queue, check if it needs to be expired,
+         * or if we want to idle in case it has no pending requests.
+         */
+        if (cfqd->active_queue == cfqq) {
+                if (time_after(now, cfqq->slice_end))
+                        cfq_slice_expired(cfqd, 0);
+                else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
+                        if (!cfq_arm_slice_timer(cfqd, cfqq))
+                                cfq_schedule_dispatch(cfqd);
+                }
+        }
 }
 
 static struct request *
@@ -1910,7 +1938,6 @@ static inline int
 __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                 struct task_struct *task, int rw)
 {
-#if 1
         if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
             !cfq_cfqq_must_alloc_slice(cfqq)) {
                 cfq_mark_cfqq_must_alloc_slice(cfqq);
@@ -1918,39 +1945,6 @@ __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         }
 
         return ELV_MQUEUE_MAY;
-#else
-        if (!cfqq || task->flags & PF_MEMALLOC)
-                return ELV_MQUEUE_MAY;
-        if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) {
-                if (cfq_cfqq_wait_request(cfqq))
-                        return ELV_MQUEUE_MUST;
-
-                /*
-                 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
-                 * can quickly flood the queue with writes from a single task
-                 */
-                if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) {
-                        cfq_mark_cfqq_must_alloc_slice(cfqq);
-                        return ELV_MQUEUE_MUST;
-                }
-
-                return ELV_MQUEUE_MAY;
-        }
-        if (cfq_class_idle(cfqq))
-                return ELV_MQUEUE_NO;
-        if (cfqq->allocated[rw] >= cfqd->max_queued) {
-                struct io_context *ioc = get_io_context(GFP_ATOMIC);
-                int ret = ELV_MQUEUE_NO;
-
-                if (ioc && ioc->nr_batch_requests)
-                        ret = ELV_MQUEUE_MAY;
-
-                put_io_context(ioc);
-                return ret;
-        }
-
-        return ELV_MQUEUE_MAY;
-#endif
 }
 
 static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
@@ -1979,16 +1973,13 @@ static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
 static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
 {
         struct cfq_data *cfqd = q->elevator->elevator_data;
-        struct request_list *rl = &q->rq;
 
-        if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) {
+        if (unlikely(cfqd->rq_starved)) {
+                struct request_list *rl = &q->rq;
+
                 smp_mb();
                 if (waitqueue_active(&rl->wait[READ]))
                         wake_up(&rl->wait[READ]);
-        }
-
-        if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) {
-                smp_mb();
                 if (waitqueue_active(&rl->wait[WRITE]))
                         wake_up(&rl->wait[WRITE]);
         }
@@ -2062,7 +2053,7 @@ 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(&crq->rb_node);
+                RB_CLEAR_NODE(&crq->rb_node);
                 crq->rb_key = 0;
                 crq->request = rq;
                 INIT_HLIST_NODE(&crq->hash);
@@ -2148,16 +2139,13 @@ static void cfq_idle_slice_timer(unsigned long data)
                  * only expire and reinvoke request handler, if there are
                  * other queues with pending requests
                  */
-                if (!cfqd->busy_queues) {
-                        cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
-                        add_timer(&cfqd->idle_slice_timer);
+                if (!cfqd->busy_queues)
                         goto out_cont;
-                }
 
                 /*
                  * not expired and it has a request pending, let it dispatch
                  */
-                if (!RB_EMPTY(&cfqq->sort_list)) {
+                if (!RB_EMPTY_ROOT(&cfqq->sort_list)) {
                         cfq_mark_cfqq_must_dispatch(cfqq);
                         goto out_kick;
                 }
@@ -2278,9 +2266,6 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
 
         cfqd->queue = q;
 
-        cfqd->max_queued = q->nr_requests / 4;
-        q->nr_batching = cfq_queued;
-
         init_timer(&cfqd->idle_slice_timer);
         cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
         cfqd->idle_slice_timer.data = (unsigned long) cfqd;
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index c94de8e12fbf..4469dd84623c 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -30,8 +30,7 @@ static const int deadline_hash_shift = 5;
 #define DL_HASH_FN(sec)         (hash_long(DL_HASH_BLOCK((sec)), deadline_hash_shift))
 #define DL_HASH_ENTRIES         (1 << deadline_hash_shift)
 #define rq_hash_key(rq)         ((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)    list_entry((ptr), struct deadline_rq, hash)
-#define ON_HASH(drq)            (drq)->on_hash
+#define ON_HASH(drq)            (!hlist_unhashed(&(drq)->hash))
 
 struct deadline_data {
         /*
@@ -48,7 +47,7 @@ struct deadline_data {
          * next in sort order. read, write or both are NULL
          */
         struct deadline_rq *next_drq[2];
-        struct list_head *hash;         /* request hash */
+        struct hlist_head *hash;        /* request hash */
         unsigned int batching;          /* number of sequential requests made */
         sector_t last_sector;           /* head position */
         unsigned int starved;           /* times reads have starved writes */
@@ -79,8 +78,7 @@ struct deadline_rq {
         /*
          * request hash, key is the ending offset (for back merge lookup)
          */
-        struct list_head hash;
-        char on_hash;
+        struct hlist_node hash;
 
         /*
          * expire fifo
@@ -100,8 +98,7 @@ static kmem_cache_t *drq_pool;
  */
 static inline void __deadline_del_drq_hash(struct deadline_rq *drq)
 {
-        drq->on_hash = 0;
-        list_del_init(&drq->hash);
+        hlist_del_init(&drq->hash);
 }
 
 static inline void deadline_del_drq_hash(struct deadline_rq *drq)
@@ -117,8 +114,7 @@ deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
 
         BUG_ON(ON_HASH(drq));
 
-        drq->on_hash = 1;
-        list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]);
+        hlist_add_head(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]);
 }
 
 /*
@@ -128,26 +124,24 @@ static inline void
 deadline_hot_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
 {
         struct request *rq = drq->request;
-        struct list_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))];
+        struct hlist_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))];
 
-        if (ON_HASH(drq) && drq->hash.prev != head) {
-                list_del(&drq->hash);
-                list_add(&drq->hash, head);
+        if (ON_HASH(drq) && &drq->hash != head->first) {
+                hlist_del(&drq->hash);
+                hlist_add_head(&drq->hash, head);
         }
 }
 
 static struct request *
 deadline_find_drq_hash(struct deadline_data *dd, sector_t offset)
 {
-        struct list_head *hash_list = &dd->hash[DL_HASH_FN(offset)];
-        struct list_head *entry, *next = hash_list->next;
+        struct hlist_head *hash_list = &dd->hash[DL_HASH_FN(offset)];
+        struct hlist_node *entry, *next;
+        struct deadline_rq *drq;
 
-        while ((entry = next) != hash_list) {
-                struct deadline_rq *drq = list_entry_hash(entry);
+        hlist_for_each_entry_safe(drq, entry, next, hash_list, hash) {
                 struct request *__rq = drq->request;
 
-                next = entry->next;
-                
                 BUG_ON(!ON_HASH(drq));
 
                 if (!rq_mergeable(__rq)) {
@@ -165,9 +159,6 @@ deadline_find_drq_hash(struct deadline_data *dd, sector_t offset)
 /*
  * rb tree support functions
  */
-#define RB_EMPTY(root)  ((root)->rb_node == NULL)
-#define ON_RB(node)     (rb_parent(node) != node)
-#define RB_CLEAR(node)  (rb_set_parent(node, node))
 #define rb_entry_drq(node)      rb_entry((node), struct deadline_rq, rb_node)
 #define DRQ_RB_ROOT(dd, drq)    (&(dd)->sort_list[rq_data_dir((drq)->request)])
 #define rq_rb_key(rq)           (rq)->sector
@@ -226,9 +217,9 @@ deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
                         dd->next_drq[data_dir] = rb_entry_drq(rbnext);
         }
 
-        BUG_ON(!ON_RB(&drq->rb_node));
+        BUG_ON(!RB_EMPTY_NODE(&drq->rb_node));
         rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
-        RB_CLEAR(&drq->rb_node);
+        RB_CLEAR_NODE(&drq->rb_node);
 }
 
 static struct request *
@@ -502,7 +493,7 @@ static int deadline_dispatch_requests(request_queue_t *q, int force)
          */
 
         if (reads) {
-                BUG_ON(RB_EMPTY(&dd->sort_list[READ]));
+                BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));
 
                 if (writes && (dd->starved++ >= dd->writes_starved))
                         goto dispatch_writes;
@@ -518,7 +509,7 @@ static int deadline_dispatch_requests(request_queue_t *q, int force)
 
         if (writes) {
 dispatch_writes:
-                BUG_ON(RB_EMPTY(&dd->sort_list[WRITE]));
+                BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE]));
 
                 dd->starved = 0;
 
@@ -625,7 +616,7 @@ static void *deadline_init_queue(request_queue_t *q, elevator_t *e)
                 return NULL;
         memset(dd, 0, sizeof(*dd));
 
-        dd->hash = kmalloc_node(sizeof(struct list_head)*DL_HASH_ENTRIES,
+        dd->hash = kmalloc_node(sizeof(struct hlist_head)*DL_HASH_ENTRIES,
                                 GFP_KERNEL, q->node);
         if (!dd->hash) {
                 kfree(dd);
@@ -641,7 +632,7 @@ static void *deadline_init_queue(request_queue_t *q, elevator_t *e)
         }
 
         for (i = 0; i < DL_HASH_ENTRIES; i++)
-                INIT_LIST_HEAD(&dd->hash[i]);
+                INIT_HLIST_HEAD(&dd->hash[i]);
 
         INIT_LIST_HEAD(&dd->fifo_list[READ]);
         INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
@@ -674,11 +665,10 @@ deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
         drq = mempool_alloc(dd->drq_pool, gfp_mask);
         if (drq) {
                 memset(drq, 0, sizeof(*drq));
-                RB_CLEAR(&drq->rb_node);
+                RB_CLEAR_NODE(&drq->rb_node);
                 drq->request = rq;
 
-                INIT_LIST_HEAD(&drq->hash);
-                drq->on_hash = 0;
+                INIT_HLIST_NODE(&drq->hash);
 
                 INIT_LIST_HEAD(&drq->fifo);
 
diff --git a/block/elevator.c b/block/elevator.c
index a0afdd317cef..d00b283f31d2 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -850,12 +850,9 @@ fail_register:
          * one again (along with re-adding the sysfs dir)
          */
         elevator_exit(e);
-        e = NULL;
         q->elevator = old_elevator;
         elv_register_queue(q);
         clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-        if (e)
-                kobject_put(&e->kobj);
         return 0;
 }
 
diff --git a/block/genhd.c b/block/genhd.c
index 5a8d3bf02f17..8d7339511e5e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -17,8 +17,7 @@
 #include <linux/buffer_head.h>
 #include <linux/mutex.h>
 
-static struct subsystem block_subsys;
-
+struct subsystem block_subsys;
 static DEFINE_MUTEX(block_subsys_lock);
 
 /*
@@ -511,9 +510,7 @@ static struct kset_uevent_ops block_uevent_ops = {
         .uevent         = block_uevent,
 };
 
-/* declare block_subsys. */
-static decl_subsys(block, &ktype_block, &block_uevent_ops);
-
+decl_subsys(block, &ktype_block, &block_uevent_ops);
 
 /*
  * aggregate disk stat collector.  Uses the same stats that the sysfs
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 7eb36c53f4b7..0603ab2f3692 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -638,7 +638,7 @@ void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr)
         /* Assume anything <= 4GB can be handled by IOMMU.
            Actually some IOMMUs can handle everything, but I don't
            know of a way to test this here. */
-        if (bounce_pfn < (0xffffffff>>PAGE_SHIFT))
+        if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
                 dma = 1;
         q->bounce_pfn = max_low_pfn;
 #else
@@ -1663,6 +1663,8 @@ static void blk_unplug_timeout(unsigned long data)
  **/
 void blk_start_queue(request_queue_t *q)
 {
+        WARN_ON(!irqs_disabled());
+
         clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
 
         /*
@@ -1878,7 +1880,8 @@ EXPORT_SYMBOL(blk_alloc_queue_node);
  *    get dealt with eventually.
  *
  *    The queue spin lock must be held while manipulating the requests on the
- *    request queue.
+ *    request queue; this lock will be taken also from interrupt context, so irq
+ *    disabling is needed for it.
  *
  *    Function returns a pointer to the initialized request queue, or NULL if
  *    it didn't succeed.
@@ -2824,6 +2827,9 @@ static void init_request_from_bio(struct request *req, struct bio *bio)
         if (unlikely(bio_barrier(bio)))
                 req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
 
+        if (bio_sync(bio))
+                req->flags |= REQ_RW_SYNC;
+
         req->errors = 0;
         req->hard_sector = req->sector = bio->bi_sector;
         req->hard_nr_sectors = req->nr_sectors = bio_sectors(bio);
@@ -3359,12 +3365,11 @@ EXPORT_SYMBOL(end_that_request_chunk);
  */
 static void blk_done_softirq(struct softirq_action *h)
 {
-        struct list_head *cpu_list;
-        LIST_HEAD(local_list);
+        struct list_head *cpu_list, local_list;
 
         local_irq_disable();
         cpu_list = &__get_cpu_var(blk_cpu_done);
-        list_splice_init(cpu_list, &local_list);
+        list_replace_init(cpu_list, &local_list);
         local_irq_enable();
 
         while (!list_empty(&local_list)) {