UBI: Add ubi_open_volume_path
Add an 'ubi_open_volume_path(path, mode)' function which works like
'open_bdev_exclusive(path, mode, ...)' where path is the special file
representing the UBI volume, typically /dev/ubi0_0.
This is needed to teach UBIFS being able to mount UBI character devices.
[Comments and the patch were amended a bit by Artem]
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 88a72e9..277786e 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -22,6 +22,8 @@
#include <linux/module.h>
#include <linux/err.h>
+#include <linux/namei.h>
+#include <linux/fs.h>
#include <asm/div64.h>
#include "ubi.h"
@@ -280,6 +282,44 @@
EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
/**
+ * ubi_open_volume_path - open UBI volume by its character device node path.
+ * @pathname: volume character device node path
+ * @mode: open mode
+ *
+ * This function is similar to 'ubi_open_volume()', but opens a volume the path
+ * to its character device node.
+ */
+struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
+{
+ int error, ubi_num, vol_id;
+ struct ubi_volume_desc *ret;
+ struct inode *inode;
+ struct path path;
+
+ dbg_gen("open volume %s, mode %d", pathname, mode);
+
+ if (!pathname || !*pathname)
+ return ERR_PTR(-EINVAL);
+
+ error = kern_path(pathname, LOOKUP_FOLLOW, &path);
+ if (error)
+ return ERR_PTR(error);
+
+ inode = path.dentry->d_inode;
+ ubi_num = ubi_major2num(imajor(inode));
+ vol_id = iminor(inode) - 1;
+
+ if (vol_id >= 0 && ubi_num >= 0)
+ ret = ubi_open_volume(ubi_num, vol_id, mode);
+ else
+ ret = ERR_PTR(-ENODEV);
+
+ path_put(&path);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ubi_open_volume_path);
+
+/**
* ubi_close_volume - close UBI volume.
* @desc: volume descriptor
*/