Change the failed_ios list in the multipath structure from a stack to a queue
using the new bio_list services.

[Kevin Corry]
--- diff/drivers/md/dm-mpath.c	2004-01-16 14:37:04.000000000 +0000
+++ source/drivers/md/dm-mpath.c	2004-01-16 14:38:03.000000000 +0000
@@ -7,6 +7,7 @@
 #include "dm.h"
 #include "dm-daemon.h"
 #include "dm-path-selector.h"
+#include "dm-bio-list.h"
 
 #include <linux/ctype.h>
 #include <linux/init.h>
@@ -59,7 +60,7 @@
 	unsigned min_io;
 
 	spinlock_t failed_lock;
-	struct bio *failed_ios;
+	struct bio_list failed_ios;
 
 	unsigned test_interval;
 	atomic_t trigger_event;
@@ -238,8 +239,7 @@
 	struct bio *bio, *next_bio;
 
 	spin_lock_irqsave(&m->failed_lock, flags);
-	bio = m->failed_ios;
-	m->failed_ios = NULL;
+	bio = bio_list_get(&m->failed_ios);
 	spin_unlock_irqrestore(&m->failed_lock, flags);
 
 	while (bio) {
@@ -690,8 +690,7 @@
 		if (!r) {
 			/* queue for the daemon to resubmit */
 			spin_lock_irqsave(&m->failed_lock, flags);
-			bio->bi_next = m->failed_ios;
-			m->failed_ios = bio;
+			bio_list_add(&m->failed_ios, bio);
 			spin_unlock_irqrestore(&m->failed_lock, flags);
 
 			dm_daemon_wake(&_kmpathd);