[PATCH] ifdef blktrace debugging fields

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/block/blktrace.c b/block/blktrace.c
index 2b4ef2b..8ff3344 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -450,8 +450,10 @@
  **/
 void blk_trace_shutdown(request_queue_t *q)
 {
-	blk_trace_startstop(q, 0);
-	blk_trace_remove(q);
+	if (q->blk_trace) {
+		blk_trace_startstop(q, 0);
+		blk_trace_remove(q);
+	}
 }
 
 /*
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 9c3a06b..51dc0ed 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1847,8 +1847,7 @@
 	if (q->queue_tags)
 		__blk_queue_free_tags(q);
 
-	if (q->blk_trace)
-		blk_trace_shutdown(q);
+	blk_trace_shutdown(q);
 
 	kmem_cache_free(requestq_cachep, q);
 }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c773ee5..cfde8b3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -417,9 +417,9 @@
 	unsigned int		sg_timeout;
 	unsigned int		sg_reserved_size;
 	int			node;
-
+#ifdef CONFIG_BLK_DEV_IO_TRACE
 	struct blk_trace	*blk_trace;
-
+#endif
 	/*
 	 * reserved for flush operations
 	 */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2712257..3696f2f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -784,8 +784,9 @@
 	struct prio_array *array;
 
 	unsigned short ioprio;
+#ifdef CONFIG_BLK_DEV_IO_TRACE
 	unsigned int btrace_seq;
-
+#endif
 	unsigned long sleep_avg;
 	unsigned long long timestamp, last_ran;
 	unsigned long long sched_time; /* sched_clock time spent running */
diff --git a/kernel/fork.c b/kernel/fork.c
index 802b1cf..bca6ce6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -183,7 +183,9 @@
 	/* One for us, one for whoever does the "release_task()" (usually parent) */
 	atomic_set(&tsk->usage,2);
 	atomic_set(&tsk->fs_excl, 0);
+#ifdef CONFIG_BLK_DEV_IO_TRACE
 	tsk->btrace_seq = 0;
+#endif
 	tsk->splice_pipe = NULL;
 	return tsk;
 }