From 5bd838f5e4930375e3425a9f47e9ed031e60a451 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <dedekind@infradead.org>
Date: Wed, 11 Oct 2006 14:52:45 +0300
Subject: [PATCH] --- yaml --- r: 45674 b: refs/heads/master c:
 9fe912cea32aec18f860c95e8574410b5892481b h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/drivers/mtd/mtdcore.c   | 37 ++++++++++++++++++++++++++++-------
 trunk/include/linux/mtd/mtd.h |  7 +++++++
 3 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/[refs] b/[refs]
index 3452355b669e..92c2f94f0c49 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7799308f34d3c3371a319559687c78c0f2506fcf
+refs/heads/master: 9fe912cea32aec18f860c95e8574410b5892481b
diff --git a/trunk/drivers/mtd/mtdcore.c b/trunk/drivers/mtd/mtdcore.c
index 06ec9f836ae5..f11f55f02413 100644
--- a/trunk/drivers/mtd/mtdcore.c
+++ b/trunk/drivers/mtd/mtdcore.c
@@ -214,12 +214,23 @@ struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 			ret = NULL;
 	}
 
-	if (ret && !try_module_get(ret->owner))
+	if (!ret)
+		goto out_unlock;
+
+	if (!try_module_get(ret->owner)) {
+		ret = NULL;
+		goto out_unlock;
+	}
+
+	if (ret->get_device && ret->get_device(ret)) {
+		module_put(ret->owner);
 		ret = NULL;
+		goto out_unlock;
+	}
 
-	if (ret)
-		ret->usecount++;
+	ret->usecount++;
 
+out_unlock:
 	mutex_unlock(&mtd_table_mutex);
 	return ret;
 }
@@ -235,8 +246,8 @@ struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 
 struct mtd_info *get_mtd_device_nm(const char *name)
 {
-	int i;
-	struct mtd_info *mtd = ERR_PTR(-ENODEV);
+	int i, err = -ENODEV;
+	struct mtd_info *mtd = NULL;
 
 	mutex_lock(&mtd_table_mutex);
 
@@ -247,17 +258,27 @@ struct mtd_info *get_mtd_device_nm(const char *name)
 		}
 	}
 
-	if (i == MAX_MTD_DEVICES)
+	if (!mtd)
 		goto out_unlock;
 
 	if (!try_module_get(mtd->owner))
 		goto out_unlock;
 
+	if (mtd->get_device) {
+		err = mtd->get_device(mtd);
+		if (err)
+			goto out_put;
+	}
+
 	mtd->usecount++;
+	mutex_unlock(&mtd_table_mutex);
+	return mtd;
 
+out_put:
+	module_put(mtd->owner);
 out_unlock:
 	mutex_unlock(&mtd_table_mutex);
-	return mtd;
+	return ERR_PTR(err);
 }
 
 void put_mtd_device(struct mtd_info *mtd)
@@ -266,6 +287,8 @@ void put_mtd_device(struct mtd_info *mtd)
 
 	mutex_lock(&mtd_table_mutex);
 	c = --mtd->usecount;
+	if (mtd->put_device)
+		mtd->put_device(mtd);
 	mutex_unlock(&mtd_table_mutex);
 	BUG_ON(c < 0);
 
diff --git a/trunk/include/linux/mtd/mtd.h b/trunk/include/linux/mtd/mtd.h
index 89e937dfef55..d644e57703ad 100644
--- a/trunk/include/linux/mtd/mtd.h
+++ b/trunk/include/linux/mtd/mtd.h
@@ -207,6 +207,13 @@ struct mtd_info {
 
 	struct module *owner;
 	int usecount;
+
+	/* If the driver is something smart, like UBI, it may need to maintain
+	 * its own reference counting. The below functions are only for driver.
+	 * The driver may register its callbacks. These callbacks are not
+	 * supposed to be called by MTD users */
+	int (*get_device) (struct mtd_info *mtd);
+	void (*put_device) (struct mtd_info *mtd);
 };