X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=block%2Felevator.c;h=24b702d649a953977cafb7125ca1b81d73947cc3;hb=0e8ed479125a6d246e17cfe6c24e140bfeb01972;hp=99a4d7b2f8ad335079ae1eebeab71136f20acc35;hpb=8e9c238c3884c226f0cddc31cde87dd5df1a6500;p=powerpc.git

diff --git a/block/elevator.c b/block/elevator.c
index 99a4d7b2f8..24b702d649 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -139,28 +139,16 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e,
 
 static char chosen_elevator[16];
 
-static void elevator_setup_default(void)
+static int __init elevator_setup(char *str)
 {
-	struct elevator_type *e;
-
 	/*
-	 * If default has not been set, use the compiled-in selection.
+	 * Be backwards-compatible with previous kernels, so users
+	 * won't get the wrong elevator.
 	 */
-	if (!chosen_elevator[0])
-		strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED);
-
- 	/*
- 	 * If the given scheduler is not available, fall back to no-op.
- 	 */
- 	if ((e = elevator_find(chosen_elevator)))
-		elevator_put(e);
+	if (!strcmp(str, "as"))
+		strcpy(chosen_elevator, "anticipatory");
 	else
- 		strcpy(chosen_elevator, "noop");
-}
-
-static int __init elevator_setup(char *str)
-{
-	strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
+		strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
 	return 0;
 }
 
@@ -177,14 +165,16 @@ int elevator_init(request_queue_t *q, char *name)
 	q->end_sector = 0;
 	q->boundary_rq = NULL;
 
-	elevator_setup_default();
+	if (name && !(e = elevator_get(name)))
+		return -EINVAL;
 
-	if (!name)
-		name = chosen_elevator;
+	if (!e && *chosen_elevator && !(e = elevator_get(chosen_elevator)))
+		printk("I/O scheduler %s not found\n", chosen_elevator);
 
-	e = elevator_get(name);
-	if (!e)
-		return -EINVAL;
+	if (!e && !(e = elevator_get(CONFIG_DEFAULT_IOSCHED))) {
+		printk("Default I/O scheduler not found, using no-op\n");
+		e = elevator_get("noop");
+	}
 
 	eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
 	if (!eq) {
@@ -303,7 +293,7 @@ void elv_requeue_request(request_queue_t *q, struct request *rq)
 
 	rq->flags &= ~REQ_STARTED;
 
-	__elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE, 0);
+	elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
 }
 
 static void elv_drain_elevator(request_queue_t *q)
@@ -320,40 +310,11 @@ static void elv_drain_elevator(request_queue_t *q)
 	}
 }
 
-void __elv_add_request(request_queue_t *q, struct request *rq, int where,
-		       int plug)
+void elv_insert(request_queue_t *q, struct request *rq, int where)
 {
 	struct list_head *pos;
 	unsigned ordseq;
 
-	if (q->ordcolor)
-		rq->flags |= REQ_ORDERED_COLOR;
-
-	if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
-		/*
-		 * toggle ordered color
-		 */
-		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)) {
-			q->end_sector = rq_end_sector(rq);
-			q->boundary_rq = rq;
-		}
-	} else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
-		where = ELEVATOR_INSERT_BACK;
-
-	if (plug)
-		blk_plug_device(q);
-
 	rq->q = q;
 
 	switch (where) {
@@ -434,6 +395,42 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where,
 	}
 }
 
+void __elv_add_request(request_queue_t *q, struct request *rq, int where,
+		       int plug)
+{
+	if (q->ordcolor)
+		rq->flags |= REQ_ORDERED_COLOR;
+
+	if (rq->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)) {
+			q->end_sector = rq_end_sector(rq);
+			q->boundary_rq = rq;
+		}
+	} else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
+		where = ELEVATOR_INSERT_BACK;
+
+	if (plug)
+		blk_plug_device(q);
+
+	elv_insert(q, rq, where);
+}
+
 void elv_add_request(request_queue_t *q, struct request *rq, int where,
 		     int plug)
 {
@@ -610,23 +607,23 @@ void elv_completed_request(request_queue_t *q, struct request *rq)
 	 * request is released from the driver, io must be done
 	 */
 	if (blk_account_rq(rq)) {
-		struct request *first_rq = list_entry_rq(q->queue_head.next);
-
 		q->in_flight--;
+		if (blk_sorted_rq(rq) && 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 (q->ordseq && q->in_flight == 0 &&
+	/*
+	 * Check if the queue is waiting for fs requests to be
+	 * drained for flush sequence.
+	 */
+	if (unlikely(q->ordseq)) {
+		struct request *first_rq = list_entry_rq(q->queue_head.next);
+		if (q->in_flight == 0 &&
 		    blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN &&
 		    blk_ordered_req_seq(first_rq) > QUEUE_ORDSEQ_DRAIN) {
 			blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0);
 			q->request_fn(q);
 		}
-
-		if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn)
-			e->ops->elevator_completed_req_fn(q, rq);
 	}
 }
 
@@ -662,8 +659,10 @@ int elv_register(struct elevator_type *e)
 	spin_unlock_irq(&elv_list_lock);
 
 	printk(KERN_INFO "io scheduler %s registered", e->elevator_name);
-	if (!strcmp(e->elevator_name, chosen_elevator))
-		printk(" (default)");
+	if (!strcmp(e->elevator_name, chosen_elevator) ||
+			(!*chosen_elevator &&
+			 !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED)))
+				printk(" (default)");
 	printk("\n");
 	return 0;
 }