From cf471bb67012a65d76e84dd12c64a1450eb2ffe4 Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@suse.com>
Date: Mon, 26 Jun 2006 00:27:21 -0700
Subject: [PATCH] --- yaml --- r: 30335 b: refs/heads/master c:
 ba61fdd17d73ddb5c892a9f12383c6c560a20d56 h: refs/heads/master i:   30333:
 a6be5cc3a5e7bb75895b5174467c6366b93696c0   30331:
 f1520bc1bbb5e2020c8fdb1f0db2f6b17f6806b9   30327:
 354289f807bf08175ebce50cf90f490c92933191   30319:
 a60a77b50394d2c76175b39c744c42eb3f09f6a6   30303:
 63605b50b5a0977966c0938208e9d049fec0b05d   30271:
 9144775590c99a54ee9fdda2e4ac2c835a52d5c6   30207:
 589ad079c10345de9d684b9e90fc5c2d801c6fff v: v3

---
 [refs]                |  2 +-
 trunk/drivers/md/dm.c | 19 ++++++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 97259dce9351..0fa04d8df010 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5806f07cd2c32920d5105e0f9ff3117338f34eec
+refs/heads/master: ba61fdd17d73ddb5c892a9f12383c6c560a20d56
diff --git a/trunk/drivers/md/dm.c b/trunk/drivers/md/dm.c
index 4d710b7a133b..87d8ca1121e2 100644
--- a/trunk/drivers/md/dm.c
+++ b/trunk/drivers/md/dm.c
@@ -54,6 +54,8 @@ union map_info *dm_get_mapinfo(struct bio *bio)
         return NULL;
 }
 
+#define MINOR_ALLOCED ((void *)-1)
+
 /*
  * Bits for the md->flags field.
  */
@@ -777,7 +779,7 @@ static int specific_minor(struct mapped_device *md, unsigned int minor)
 		goto out;
 	}
 
-	r = idr_get_new_above(&_minor_idr, md, minor, &m);
+	r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
 	if (r) {
 		goto out;
 	}
@@ -806,7 +808,7 @@ static int next_free_minor(struct mapped_device *md, unsigned int *minor)
 		goto out;
 	}
 
-	r = idr_get_new(&_minor_idr, md, &m);
+	r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
 	if (r) {
 		goto out;
 	}
@@ -833,6 +835,7 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
 {
 	int r;
 	struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
+	void *old_md;
 
 	if (!md) {
 		DMWARN("unable to allocate device, out of memory.");
@@ -888,6 +891,13 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
 	init_waitqueue_head(&md->wait);
 	init_waitqueue_head(&md->eventq);
 
+	/* Populate the mapping, nobody knows we exist yet */
+	mutex_lock(&_minor_lock);
+	old_md = idr_replace(&_minor_idr, md, minor);
+	mutex_unlock(&_minor_lock);
+
+	BUG_ON(old_md != MINOR_ALLOCED);
+
 	return md;
 
  bad4:
@@ -1018,7 +1028,7 @@ static struct mapped_device *dm_find_md(dev_t dev)
 	mutex_lock(&_minor_lock);
 
 	md = idr_find(&_minor_idr, minor);
-	if (!md || (dm_disk(md)->first_minor != minor))
+	if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor)))
 		md = NULL;
 
 	mutex_unlock(&_minor_lock);
@@ -1057,6 +1067,9 @@ void dm_put(struct mapped_device *md)
 
 	if (atomic_dec_and_test(&md->holders)) {
 		map = dm_get_table(md);
+		mutex_lock(&_minor_lock);
+		idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor);
+		mutex_unlock(&_minor_lock);
 		if (!dm_suspended(md)) {
 			dm_table_presuspend_targets(map);
 			dm_table_postsuspend_targets(map);