>From bd918c40d92e4f074763a88bc8f13593c4f2dc52 Mon Sep 17 00:00:00 2001
From: Alan D. Brunelle <alan.brunelle@hp.com>
Date: Fri, 24 Apr 2009 17:30:32 -0400
Subject: [PATCH] Added in blktrace msgs for dm-ioband

Added the following messages:

In hold_bio - added messages as they are being added to either the
urgent or normal hold lists.

  ioband <g_name> hold_urg <g_blocked>
  ioband <g_name> hold_nrm <g_blocked>

In make_issue_list - added messages when placing previously held bios
onto either the pushback or issue lists:

  ioband <g_name> add_pback <g_blocked> <c_blocked>
  ioband <g_name> add_iss <g_blocked> <c_blocked>

In release_urgent bios - added a message indicating that an urgent bio
was added to the issue list:

  ioband <g_name> urg_add_iss> <g_blocked>

In ioband_conduct - added messages as bios are being popped and executed
(sent to generic_make_request) or pushed back (bio_endio):

  ioband <g_name> pop_iss
  ioband <g_name> pop_pback

Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com>
---
 drivers/md/dm-ioband-ctl.c |   30 +++++++++++++++++++++++++++---
 1 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-ioband-ctl.c b/drivers/md/dm-ioband-ctl.c
index 29bef11..26ad7a5 100644
--- a/drivers/md/dm-ioband-ctl.c
+++ b/drivers/md/dm-ioband-ctl.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/rbtree.h>
+#include <linux/blktrace_api.h>
 #include "dm.h"
 #include "md.h"
 #include "dm-bio-list.h"
@@ -633,9 +634,15 @@ static void hold_bio(struct ioband_group *gp, struct bio *bio)
 		 */
 		dp->g_prepare_bio(gp, bio, IOBAND_URGENT);
 		bio_list_add(&dp->g_urgent_bios, bio);
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s hold_urg %d", dp->g_name,
+				  dp->g_blocked);
 	} else {
 		gp->c_blocked++;
 		dp->g_hold_bio(gp, bio);
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s hold_nrm %d", dp->g_name,
+				  gp->c_blocked);
 	}
 }
 
@@ -676,14 +683,21 @@ static int make_issue_list(struct ioband_group *gp, struct bio *bio,
 		clear_group_blocked(gp);
 		wake_up_all(&gp->c_waitq);
 	}
-	if (should_pushback_bio(gp))
+	if (should_pushback_bio(gp)) {
 		bio_list_add(pushback_list, bio);
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s add_pback %d %d", dp->g_name,
+				  dp->g_blocked, gp->c_blocked);
+	}
 	else {
 		int rw = bio_data_dir(bio);
 
 		gp->c_stat[rw].deferred++;
 		gp->c_stat[rw].sectors += bio_sectors(bio);
 		bio_list_add(issue_list, bio);
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s add_iss %d %d", dp->g_name,
+				  dp->g_blocked, gp->c_blocked);
 	}
 	return prepare_to_issue(gp, bio);
 }
@@ -703,6 +717,9 @@ static void release_urgent_bios(struct ioband_device *dp,
 		dp->g_blocked--;
 		dp->g_issued[bio_data_dir(bio)]++;
 		bio_list_add(issue_list, bio);
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s urg_add_iss %d", dp->g_name,
+				  dp->g_blocked);
 	}
 }
 
@@ -916,10 +933,17 @@ static void ioband_conduct(struct work_struct *work)
 
 	spin_unlock_irqrestore(&dp->g_lock, flags);
 
-	while ((bio = bio_list_pop(&issue_list)))
+	while ((bio = bio_list_pop(&issue_list))) {
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s pop_iss", dp->g_name);
 		generic_make_request(bio);
-	while ((bio = bio_list_pop(&pushback_list)))
+	}
+
+	while ((bio = bio_list_pop(&pushback_list))) {
+		blk_add_trace_msg(bdev_get_queue(bio->bi_bdev),
+				  "ioband %s pop_pback", dp->g_name);
 		bio_endio(bio, -EIO);
+	}
 }
 
 static int ioband_end_io(struct dm_target *ti, struct bio *bio,
-- 
1.5.6.3