[MTD] add get and put methods
This patch adds get_device() and put_device() methods to the MTD description
structure (struct mtd_info). These methods are called by MTD whenever the MTD
device is get or put. They are needed when the underlying driver is something
smarter then just flash chip driver, for example UBI.
Signed-off-by: Artem Bityutskiy <dedekind@infradead.org>
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 06ec9f8..f11f55f 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -214,12 +214,23 @@
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)
- ret->usecount++;
+ if (ret->get_device && ret->get_device(ret)) {
+ module_put(ret->owner);
+ ret = NULL;
+ goto out_unlock;
+ }
+ ret->usecount++;
+
+out_unlock:
mutex_unlock(&mtd_table_mutex);
return ret;
}
@@ -235,8 +246,8 @@
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 @@
}
}
- if (i == MAX_MTD_DEVICES)
+ if (!mtd)
goto out_unlock;
if (!try_module_get(mtd->owner))
goto out_unlock;
- mtd->usecount++;
+ if (mtd->get_device) {
+ err = mtd->get_device(mtd);
+ if (err)
+ goto out_put;
+ }
-out_unlock:
+ mtd->usecount++;
mutex_unlock(&mtd_table_mutex);
return mtd;
+
+out_put:
+ module_put(mtd->owner);
+out_unlock:
+ mutex_unlock(&mtd_table_mutex);
+ return ERR_PTR(err);
}
void put_mtd_device(struct mtd_info *mtd)
@@ -266,6 +287,8 @@
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);