UBUNTU: Ubuntu-2.6.38-12.51
[linux-flexiantxendom0-natty.git] / block / elevator.c
index ca86192..236e93c 100644 (file)
@@ -79,7 +79,13 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
        /*
         * Don't merge file system requests and discard requests
         */
-       if (bio_discard(bio) != bio_discard(rq->bio))
+       if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
+               return 0;
+
+       /*
+        * Don't merge discard requests and secure discard requests
+        */
+       if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
                return 0;
 
        /*
@@ -153,10 +159,7 @@ static struct elevator_type *elevator_get(const char *name)
 
                spin_unlock(&elv_list_lock);
 
-               if (!strcmp(name, "anticipatory"))
-                       sprintf(elv, "as-iosched");
-               else
-                       sprintf(elv, "%s-iosched", name);
+               snprintf(elv, sizeof(elv), "%s-iosched", name);
 
                request_module("%s", elv);
                spin_lock(&elv_list_lock);
@@ -192,10 +195,7 @@ static int __init elevator_setup(char *str)
         * Be backwards-compatible with previous kernels, so users
         * won't get the wrong elevator.
         */
-       if (!strcmp(str, "as"))
-               strcpy(chosen_elevator, "anticipatory");
-       else
-               strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
+       strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
        return 1;
 }
 
@@ -247,9 +247,11 @@ int elevator_init(struct request_queue *q, char *name)
 {
        struct elevator_type *e = NULL;
        struct elevator_queue *eq;
-       int ret = 0;
        void *data;
 
+       if (unlikely(q->elevator))
+               return 0;
+
        INIT_LIST_HEAD(&q->queue_head);
        q->last_merge = NULL;
        q->end_sector = 0;
@@ -289,7 +291,7 @@ int elevator_init(struct request_queue *q, char *name)
        }
 
        elevator_attach(q, eq, data);
-       return ret;
+       return 0;
 }
 EXPORT_SYMBOL(elevator_init);
 
@@ -427,11 +429,12 @@ void elv_dispatch_sort(struct request_queue *q, struct request *rq)
        q->nr_sorted--;
 
        boundary = q->end_sector;
-       stop_flags = REQ_SOFTBARRIER | REQ_HARDBARRIER | REQ_STARTED;
+       stop_flags = REQ_SOFTBARRIER | REQ_STARTED;
        list_for_each_prev(entry, &q->queue_head) {
                struct request *pos = list_entry_rq(entry);
 
-               if (blk_discard_rq(rq) != blk_discard_rq(pos))
+               if ((rq->cmd_flags & REQ_DISCARD) !=
+                   (pos->cmd_flags & REQ_DISCARD))
                        break;
                if (rq_data_dir(rq) != rq_data_dir(pos))
                        break;
@@ -479,6 +482,15 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio)
        int ret;
 
        /*
+        * Levels of merges:
+        *      nomerges:  No merges at all attempted
+        *      noxmerges: Only simple one-hit cache try
+        *      merges:    All merge tries attempted
+        */
+       if (blk_queue_nomerges(q))
+               return ELEVATOR_NO_MERGE;
+
+       /*
         * First try one-hit cache.
         */
        if (q->last_merge) {
@@ -489,7 +501,7 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio)
                }
        }
 
-       if (blk_queue_nomerges(q))
+       if (blk_queue_noxmerges(q))
                return ELEVATOR_NO_MERGE;
 
        /*
@@ -535,6 +547,15 @@ void elv_merge_requests(struct request_queue *q, struct request *rq,
        q->last_merge = rq;
 }
 
+void elv_bio_merged(struct request_queue *q, struct request *rq,
+                       struct bio *bio)
+{
+       struct elevator_queue *e = q->elevator;
+
+       if (e->ops->elevator_bio_merged_fn)
+               e->ops->elevator_bio_merged_fn(q, rq, bio);
+}
+
 void elv_requeue_request(struct request_queue *q, struct request *rq)
 {
        /*
@@ -543,7 +564,7 @@ void elv_requeue_request(struct request_queue *q, struct request *rq)
         */
        if (blk_account_rq(rq)) {
                q->in_flight[rq_is_sync(rq)]--;
-               if (blk_sorted_rq(rq))
+               if (rq->cmd_flags & REQ_SORTED)
                        elv_deactivate_rq(q, rq);
        }
 
@@ -581,7 +602,7 @@ void elv_quiesce_start(struct request_queue *q)
         */
        elv_drain_elevator(q);
        while (q->rq.elvpriv) {
-               __blk_run_queue(q);
+               __blk_run_queue(q, false);
                spin_unlock_irq(q->queue_lock);
                msleep(10);
                spin_lock_irq(q->queue_lock);
@@ -596,8 +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);
@@ -605,9 +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;
 
@@ -625,11 +651,12 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
                 *   with anything.  There's no point in delaying queue
                 *   processing.
                 */
-               __blk_run_queue(q);
+               __blk_run_queue(q, false);
                break;
 
        case ELEVATOR_INSERT_SORT:
-               BUG_ON(!blk_fs_request(rq) && !blk_discard_rq(rq));
+               BUG_ON(rq->cmd_type != REQ_TYPE_FS &&
+                      !(rq->cmd_flags & REQ_DISCARD));
                rq->cmd_flags |= REQ_SORTED;
                q->nr_sorted++;
                if (rq_mergeable(rq)) {
@@ -646,36 +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);
@@ -694,27 +691,10 @@ 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 (blk_barrier_rq(rq))
-                       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
-                */
-               if (blk_fs_request(rq) || blk_discard_rq(rq)) {
+       if (rq->cmd_flags & REQ_SOFTBARRIER) {
+               /* 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);
                        q->boundary_rq = rq;
                }
@@ -828,27 +808,10 @@ void elv_completed_request(struct request_queue *q, struct request *rq)
         */
        if (blk_account_rq(rq)) {
                q->in_flight[rq_is_sync(rq)]--;
-               if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn)
+               if ((rq->cmd_flags & REQ_SORTED) &&
+                   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)
@@ -888,7 +851,7 @@ elv_attr_store(struct kobject *kobj, struct attribute *attr,
        return error;
 }
 
-static struct sysfs_ops elv_sysfs_ops = {
+static const struct sysfs_ops elv_sysfs_ops = {
        .show   = elv_attr_show,
        .store  = elv_attr_store,
 };
@@ -914,14 +877,17 @@ int elv_register_queue(struct request_queue *q)
                        }
                }
                kobject_uevent(&e->kobj, KOBJ_ADD);
+               e->registered = 1;
        }
        return error;
 }
+EXPORT_SYMBOL(elv_register_queue);
 
 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)
@@ -929,6 +895,7 @@ void elv_unregister_queue(struct request_queue *q)
        if (q)
                __elv_unregister_queue(q->elevator);
 }
+EXPORT_SYMBOL(elv_unregister_queue);
 
 void elv_register(struct elevator_type *e)
 {
@@ -983,18 +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;
        }
 
        /*
@@ -1015,10 +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.
@@ -1030,7 +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:
        /*
@@ -1045,22 +1016,22 @@ 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));
-       strstrip(elevator_name);
-
-       e = elevator_get(elevator_name);
+       e = elevator_get(strstrip(elevator_name));
        if (!e) {
                printk(KERN_ERR "elevator: type %s not found\n", elevator_name);
                return -EINVAL;
@@ -1068,13 +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)
@@ -1084,7 +1069,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
        struct elevator_type *__e;
        int len = 0;
 
-       if (!q->elevator)
+       if (!q->elevator || !blk_queue_stackable(q))
                return sprintf(name, "none\n");
 
        elv = e->elevator_type;