Merge branch 'syscore' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspen...

[pandora-kernel.git] / block / elevator.c

diff --git a/block/elevator.c b/block/elevator.c
index 236e93c..c387d31 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -113,7 +113,7 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
 }
 EXPORT_SYMBOL(elv_rq_merge_ok);
 
-static inline int elv_try_merge(struct request *__rq, struct bio *bio)
+int elv_try_merge(struct request *__rq, struct bio *bio)
 {
        int ret = ELEVATOR_NO_MERGE;
 
@@ -421,6 +421,8 @@ void elv_dispatch_sort(struct request_queue *q, struct request *rq)
        struct list_head *entry;
        int stop_flags;
 
+       BUG_ON(rq->cmd_flags & REQ_ON_PLUG);
+
        if (q->last_merge == rq)
                q->last_merge = NULL;
 
@@ -519,6 +521,40 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio)
        return ELEVATOR_NO_MERGE;
 }
 
+/*
+ * Attempt to do an insertion back merge. Only check for the case where
+ * we can append 'rq' to an existing request, so we can throw 'rq' away
+ * afterwards.
+ *
+ * Returns true if we merged, false otherwise
+ */
+static bool elv_attempt_insert_merge(struct request_queue *q,
+                                    struct request *rq)
+{
+       struct request *__rq;
+
+       if (blk_queue_nomerges(q))
+               return false;
+
+       /*
+        * First try one-hit cache.
+        */
+       if (q->last_merge && blk_attempt_req_merge(q, q->last_merge, rq))
+               return true;
+
+       if (blk_queue_noxmerges(q))
+               return false;
+
+       /*
+        * See if our hash lookup can find a potential backmerge.
+        */
+       __rq = elv_rqhash_find(q, blk_rq_pos(rq));
+       if (__rq && blk_attempt_req_merge(q, __rq, rq))
+               return true;
+
+       return false;
+}
+
 void elv_merged_request(struct request_queue *q, struct request *rq, int type)
 {
        struct elevator_queue *e = q->elevator;
@@ -536,14 +572,18 @@ void elv_merge_requests(struct request_queue *q, struct request *rq,
                             struct request *next)
 {
        struct elevator_queue *e = q->elevator;
+       const int next_sorted = next->cmd_flags & REQ_SORTED;
 
-       if (e->ops->elevator_merge_req_fn)
+       if (next_sorted && e->ops->elevator_merge_req_fn)
                e->ops->elevator_merge_req_fn(q, rq, next);
 
        elv_rqhash_reposition(q, rq);
-       elv_rqhash_del(q, next);
 
-       q->nr_sorted--;
+       if (next_sorted) {
+               elv_rqhash_del(q, next);
+               q->nr_sorted--;
+       }
+
        q->last_merge = rq;
 }
 
@@ -617,21 +657,12 @@ void elv_quiesce_end(struct request_queue *q)
 
 void elv_insert(struct request_queue *q, struct request *rq, int where)
 {
-       int unplug_it = 1;
-
        trace_block_rq_insert(q, rq);
 
        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);
@@ -654,6 +685,14 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
                __blk_run_queue(q, false);
                break;
 
+       case ELEVATOR_INSERT_SORT_MERGE:
+               /*
+                * If we succeed in merging this request with one in the
+                * queue already, we are done - rq has now been freed,
+                * so no need to do anything further.
+                */
+               if (elv_attempt_insert_merge(q, rq))
+                       break;
        case ELEVATOR_INSERT_SORT:
                BUG_ON(rq->cmd_type != REQ_TYPE_FS &&
                       !(rq->cmd_flags & REQ_DISCARD));
@@ -673,24 +712,21 @@ 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_FLUSH:
+               rq->cmd_flags |= REQ_SOFTBARRIER;
+               blk_insert_flush(rq);
+               break;
        default:
                printk(KERN_ERR "%s: bad insertion point %d\n",
                       __func__, where);
                BUG();
        }
-
-       if (unplug_it && blk_queue_plugged(q)) {
-               int nrq = q->rq.count[BLK_RW_SYNC] + q->rq.count[BLK_RW_ASYNC]
-                               - queue_in_flight(q);
-
-               if (nrq >= q->unplug_thresh)
-                       __generic_unplug_device(q);
-       }
 }
 
-void __elv_add_request(struct request_queue *q, struct request *rq, int where,
-                      int plug)
+void __elv_add_request(struct request_queue *q, struct request *rq, int where)
 {
+       BUG_ON(rq->cmd_flags & REQ_ON_PLUG);
+
        if (rq->cmd_flags & REQ_SOFTBARRIER) {
                /* barriers are scheduling boundary, update end_sector */
                if (rq->cmd_type == REQ_TYPE_FS ||
@@ -702,38 +738,20 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where,
                    where == ELEVATOR_INSERT_SORT)
                where = ELEVATOR_INSERT_BACK;
 
-       if (plug)
-               blk_plug_device(q);
-
        elv_insert(q, rq, where);
 }
 EXPORT_SYMBOL(__elv_add_request);
 
-void elv_add_request(struct request_queue *q, struct request *rq, int where,
-                    int plug)
+void elv_add_request(struct request_queue *q, struct request *rq, int where)
 {
        unsigned long flags;
 
        spin_lock_irqsave(q->queue_lock, flags);
-       __elv_add_request(q, rq, where, plug);
+       __elv_add_request(q, rq, where);
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 EXPORT_SYMBOL(elv_add_request);
 
-int elv_queue_empty(struct request_queue *q)
-{
-       struct elevator_queue *e = q->elevator;
-
-       if (!list_empty(&q->queue_head))
-               return 0;
-
-       if (e->ops->elevator_queue_empty_fn)
-               return e->ops->elevator_queue_empty_fn(q);
-
-       return 1;
-}
-EXPORT_SYMBOL(elv_queue_empty);
-
 struct request *elv_latter_request(struct request_queue *q, struct request *rq)
 {
        struct elevator_queue *e = q->elevator;
@@ -759,7 +777,7 @@ int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
        if (e->ops->elevator_set_req_fn)
                return e->ops->elevator_set_req_fn(q, rq, gfp_mask);
 
-       rq->elevator_private = NULL;
+       rq->elevator_private[0] = NULL;
        return 0;
 }
 
@@ -785,6 +803,8 @@ void elv_abort_queue(struct request_queue *q)
 {
        struct request *rq;
 
+       blk_abort_flushes(q);
+
        while (!list_empty(&q->queue_head)) {
                rq = list_entry_rq(q->queue_head.next);
                rq->cmd_flags |= REQ_QUIET;