# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.811   -> 1.812  
#	include/linux/elevator.h	1.16    -> 1.17   
#	drivers/block/ll_rw_blk.c	1.123   -> 1.124  
#	drivers/scsi/scsi_lib.c	1.35    -> 1.36   
#	 include/linux/blk.h	1.27    -> 1.28   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/28	axboe@burns.home.kernel.dk	1.812
# Request insertion in the current tree is a mess. We have all sorts of
# variants of *elv_add_request*, and it's not at all clear who does what
# and with what locks (or not). This patch cleans it up to be:
# 
# o __elv_add_request(queue, request, at_end, plug)
# 	Core function, requires queue lock to be held
# 
# o elv_add_request(queue, request, at_end, plug)
# 	Like __elv_add_request(), but grabs queue lock
# 
# o __elv_add_request_pos(queue, request, position)
# 	Insert request at a given location, lock must be held
# --------------------------------------------
#
diff -Nru a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
--- a/drivers/block/ll_rw_blk.c	Mon Oct 28 17:51:57 2002
+++ b/drivers/block/ll_rw_blk.c	Mon Oct 28 17:51:57 2002
@@ -639,7 +639,7 @@
 			blk_queue_end_tag(q, rq);
 
 		rq->flags &= ~REQ_STARTED;
-		elv_add_request(q, rq, 0);
+		__elv_add_request(q, rq, 0, 0);
 	}
 }
 
@@ -1466,7 +1466,7 @@
 	 * elevator indicated where it wants this request to be
 	 * inserted at elevator_merge time
 	 */
-	__elv_add_request(q, req, insert_here);
+	__elv_add_request_pos(q, req, insert_here);
 }
 
 /*
diff -Nru a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c	Mon Oct 28 17:51:57 2002
+++ b/drivers/scsi/scsi_lib.c	Mon Oct 28 17:51:57 2002
@@ -240,7 +240,7 @@
 		SCpnt->request->special = (void *) SCpnt;
 		if(blk_rq_tagged(SCpnt->request))
 			blk_queue_end_tag(q, SCpnt->request);
-		_elv_add_request(q, SCpnt->request, 0, 0);
+		__elv_add_request(q, SCpnt->request, 0, 0);
 	}
 
 	/*
@@ -951,7 +951,7 @@
 				SCpnt->request->flags |= REQ_SPECIAL;
 				if(blk_rq_tagged(SCpnt->request))
 					blk_queue_end_tag(q, SCpnt->request);
-				_elv_add_request(q, SCpnt->request, 0, 0);
+				__elv_add_request(q, SCpnt->request, 0, 0);
 				break;
 			}
 
diff -Nru a/include/linux/blk.h b/include/linux/blk.h
--- a/include/linux/blk.h	Mon Oct 28 17:51:57 2002
+++ b/include/linux/blk.h	Mon Oct 28 17:51:57 2002
@@ -50,22 +50,6 @@
 		elv_remove_request(req->q, req);
 }
 
-#define _elv_add_request_core(q, rq, where, plug)			\
-	do {								\
-		if ((plug))						\
-			blk_plug_device((q));				\
-		(q)->elevator.elevator_add_req_fn((q), (rq), (where));	\
-	} while (0)
-
-#define _elv_add_request(q, rq, back, p) do {				      \
-	if ((back))							      \
-		_elv_add_request_core((q), (rq), (q)->queue_head.prev, (p));  \
-	else								      \
-		_elv_add_request_core((q), (rq), &(q)->queue_head, (p));      \
-} while (0)
-
-#define elv_add_request(q, rq, back) _elv_add_request((q), (rq), (back), 1)
-
 #if defined(MAJOR_NR) || defined(IDE_DRIVER)
 #if (MAJOR_NR != SCSI_TAPE_MAJOR) && (MAJOR_NR != OSST_MAJOR)
 #if !defined(IDE_DRIVER)
diff -Nru a/include/linux/elevator.h b/include/linux/elevator.h
--- a/include/linux/elevator.h	Mon Oct 28 17:51:57 2002
+++ b/include/linux/elevator.h	Mon Oct 28 17:51:57 2002
@@ -40,8 +40,8 @@
 /*
  * block elevator interface
  */
-extern void __elv_add_request(request_queue_t *, struct request *,
-			      struct list_head *);
+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 list_head **, struct bio *);
 extern void elv_merge_requests(request_queue_t *, struct request *,
 			       struct request *);
@@ -49,6 +49,9 @@
 extern void elv_remove_request(request_queue_t *, struct request *);
 extern int elv_queue_empty(request_queue_t *);
 extern inline struct list_head *elv_get_sort_head(request_queue_t *, struct request *);
+
+#define __elv_add_request_pos(q, rq, pos)	\
+	(q)->elevator.elevator_add_req_fn((q), (rq), (pos))
 
 /*
  * noop I/O scheduler. always merges, always inserts new request at tail
diff -Nru a/drivers/block/elevator.c b/drivers/block/elevator.c
--- a/drivers/block/elevator.c	Mon Oct 28 17:54:46 2002
+++ b/drivers/block/elevator.c	Mon Oct 28 17:54:46 2002
@@ -272,13 +272,27 @@
 		e->elevator_merge_req_fn(q, rq, next);
 }
 
-/*
- * add_request and next_request are required to be supported, naturally
- */
-void __elv_add_request(request_queue_t *q, struct request *rq,
-			  struct list_head *insert_here)
+void __elv_add_request(request_queue_t *q, struct request *rq, int at_end,
+		       int plug)
 {
-	q->elevator.elevator_add_req_fn(q, rq, insert_here);
+	struct list_head *insert = &q->queue_head;
+
+	if (at_end)
+		insert = insert->prev;
+	if (plug)
+		blk_plug_device(q);
+
+	q->elevator.elevator_add_req_fn(q, rq, insert);
+}
+
+void elv_add_request(request_queue_t *q, struct request *rq, int at_end,
+		     int plug)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	__elv_add_request(q, rq, at_end, plug);
+	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 static inline struct request *__elv_next_request(request_queue_t *q)
@@ -357,6 +371,7 @@
 
 EXPORT_SYMBOL(elevator_noop);
 
+EXPORT_SYMBOL(elv_add_request);
 EXPORT_SYMBOL(__elv_add_request);
 EXPORT_SYMBOL(elv_next_request);
 EXPORT_SYMBOL(elv_remove_request);