From 40cfa2bce2cf09160da6b767603e11a2cfac3a3e Mon Sep 17 00:00:00 2001
From: guanglei <guanglei>
Date: Thu, 12 Oct 2006 08:29:10 +0000
Subject: * ioscheduler.stp:   bugfix to avoid refer to NULL pointer

* hookid_defs.stp, ioscheduler.stp, register_event.stp:
  break the old addevent.ioscheduler.elv_next_request into
  addevent.ioscheduler.elv_next_request.entry and
  addevent.ioscheduler.elv_next_request.return.
  Now log_ioscheduler_tracedata_* will use the
  variables defined in generic ioscheduler tapset
---
 tapset/ioscheduler.stp | 61 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 53 insertions(+), 8 deletions(-)

(limited to 'tapset/ioscheduler.stp')

diff --git a/tapset/ioscheduler.stp b/tapset/ioscheduler.stp
index 9fa0cca1..9c3714f4 100644
--- a/tapset/ioscheduler.stp
+++ b/tapset/ioscheduler.stp
@@ -20,8 +20,27 @@ probe ioscheduler.elv_next_request
 %:
 	elevator_name = kernel_string($q->elevator->elevator_name)
 %)
-	disk_major = disk_major_from_request($q)
-	disk_minor = disk_minor_from_request($q)
+}
+
+probe ioscheduler.elv_next_request.return
+	= kernel.function("elv_next_request").return
+{
+	if($return == 0)  {
+		req = 0
+		req_flags = 0
+		disk_major = -1
+		disk_minor = -1
+	} else {
+		req = $return
+		req_flags = $return->flags
+		if($return->rq_disk == 0)  {
+			disk_major = -1
+			disk_minor = -1
+		} else {
+			disk_major = $return->rq_disk->major
+			disk_minor = $return->rq_disk->first_minor
+		}
+	}
 }
 
 /* when a request is added to the request queue */
@@ -33,8 +52,21 @@ probe ioscheduler.elv_add_request
 %:
 	elevator_name = kernel_string($q->elevator->elevator_name)
 %)
-	disk_major = $rq->rq_disk->major
-	disk_minor = $rq->rq_disk->first_minor
+	if($rq == 0)  {
+		disk_major = -1
+		disk_minor = -1
+	} else {
+		if($rq->rq_disk == 0)  {
+			disk_major = -1
+			disk_minor = -1
+		} else {
+			disk_major = $rq->rq_disk->major
+			disk_minor = $rq->rq_disk->first_minor
+		}
+	}
+
+	req = $rq
+	req_flags = $rq->flags
 }
 
 /* when a request is completed */
@@ -46,12 +78,25 @@ probe ioscheduler.elv_completed_request
 %:
 	elevator_name = kernel_string($q->elevator->elevator_name)
 %)
-	disk_major = $rq->rq_disk->major
-	disk_minor = $rq->rq_disk->first_minor
+	if($rq == 0)  {
+		disk_major = -1
+		disk_minor = -1
+	} else {
+		if($rq->rq_disk == 0)  {
+			disk_major = -1
+			disk_minor = -1
+		} else {
+			disk_major = $rq->rq_disk->major
+			disk_minor = $rq->rq_disk->first_minor
+		}
+	}
+
+	req = $rq
+	req_flags = $rq->flags
 }
 
 function disk_major_from_request:long(var_q:long)
-%{
+%{ /* pure */
 	struct request_queue *q;
 	struct request *rq;
 
@@ -66,7 +111,7 @@ function disk_major_from_request:long(var_q:long)
 %}
 
 function disk_minor_from_request:long(var_q:long)
-%{
+%{ /* pure */
 	struct request_queue *q;
 	struct request *rq;
 
-- 
cgit