2 files changed, 31 insertions, 13 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1afbdb2d752c..fffe163316aa 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -203,6 +203,7 @@ struct request {
 enum rq_flag_bits {
         __REQ_RW,               /* not set, read. set, write */
         __REQ_FAILFAST,         /* no low level driver retries */
+        __REQ_SORTED,           /* elevator knows about this request */
         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
         __REQ_HARDBARRIER,      /* may not be passed by drive either */
         __REQ_CMD,              /* is a regular fs rw request */
@@ -235,6 +236,7 @@ enum rq_flag_bits {
 
 #define REQ_RW          (1 << __REQ_RW)
 #define REQ_FAILFAST    (1 << __REQ_FAILFAST)
+#define REQ_SORTED      (1 << __REQ_SORTED)
 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 #define REQ_CMD         (1 << __REQ_CMD)
@@ -333,6 +335,12 @@ struct request_queue
         end_flush_fn            *end_flush_fn;
 
         /*
+         * Dispatch queue sorting
+         */
+        sector_t                end_sector;
+        struct request          *boundary_rq;
+
+        /*
          * Auto-unplugging state
          */
         struct timer_list       unplug_timer;
@@ -454,6 +462,7 @@ enum {
 #define blk_pm_request(rq)      \
         ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
 
+#define blk_sorted_rq(rq)       ((rq)->flags & REQ_SORTED)
 #define blk_barrier_rq(rq)      ((rq)->flags & REQ_HARDBARRIER)
 #define blk_barrier_preflush(rq)        ((rq)->flags & REQ_BAR_PREFLUSH)
 #define blk_barrier_postflush(rq)       ((rq)->flags & REQ_BAR_POSTFLUSH)
@@ -611,12 +620,21 @@ extern void end_request(struct request *req, int uptodate);
 
 static inline void blkdev_dequeue_request(struct request *req)
 {
-        BUG_ON(list_empty(&req->queuelist));
+        elv_dequeue_request(req->q, req);
+}
 
-        list_del_init(&req->queuelist);
+/*
+ * This should be in elevator.h, but that requires pulling in rq and q
+ */
+static inline void elv_dispatch_add_tail(struct request_queue *q,
+                                         struct request *rq)
+{
+        if (q->last_merge == rq)
+                q->last_merge = NULL;
 
-        if (req->rl)
-                elv_remove_request(req->q, req);
+        q->end_sector = rq_end_sector(rq);
+        q->boundary_rq = rq;
+        list_add_tail(&rq->queuelist, &q->queue_head);
 }
 
 /*
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index ed93125c1db5..a74c27e460ba 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -8,18 +8,17 @@ typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struc
 
 typedef void (elevator_merged_fn) (request_queue_t *, struct request *);
 
-typedef struct request *(elevator_next_req_fn) (request_queue_t *);
+typedef int (elevator_dispatch_fn) (request_queue_t *, int);
 
-typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, int);
+typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
 typedef int (elevator_queue_empty_fn) (request_queue_t *);
-typedef void (elevator_remove_req_fn) (request_queue_t *, struct request *);
-typedef void (elevator_requeue_req_fn) (request_queue_t *, struct request *);
 typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);
 typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);
 typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *);
 
 typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t);
 typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
+typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *);
 typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *);
 
 typedef int (elevator_init_fn) (request_queue_t *, elevator_t *);
@@ -31,10 +30,9 @@ struct elevator_ops
         elevator_merged_fn *elevator_merged_fn;
         elevator_merge_req_fn *elevator_merge_req_fn;
 
-        elevator_next_req_fn *elevator_next_req_fn;
+        elevator_dispatch_fn *elevator_dispatch_fn;
         elevator_add_req_fn *elevator_add_req_fn;
-        elevator_remove_req_fn *elevator_remove_req_fn;
-        elevator_requeue_req_fn *elevator_requeue_req_fn;
+        elevator_activate_req_fn *elevator_activate_req_fn;
         elevator_deactivate_req_fn *elevator_deactivate_req_fn;
 
         elevator_queue_empty_fn *elevator_queue_empty_fn;
@@ -81,15 +79,15 @@ struct elevator_queue
 /*
  * block elevator interface
  */
+extern void elv_dispatch_sort(request_queue_t *, struct request *);
 extern void elv_add_request(request_queue_t *, struct request *, int, int);
 extern void __elv_add_request(request_queue_t *, struct request *, int, int);
 extern int elv_merge(request_queue_t *, struct request **, struct bio *);
 extern void elv_merge_requests(request_queue_t *, struct request *,
                                struct request *);
 extern void elv_merged_request(request_queue_t *, struct request *);
-extern void elv_remove_request(request_queue_t *, struct request *);
+extern void elv_dequeue_request(request_queue_t *, struct request *);
 extern void elv_requeue_request(request_queue_t *, struct request *);
-extern void elv_deactivate_request(request_queue_t *, struct request *);
 extern int elv_queue_empty(request_queue_t *);
 extern struct request *elv_next_request(struct request_queue *q);
 extern struct request *elv_former_request(request_queue_t *, struct request *);
@@ -142,4 +140,6 @@ enum {
         ELV_MQUEUE_MUST,
 };
 
+#define rq_end_sector(rq)       ((rq)->sector + (rq)->nr_sectors)
+
 #endif