[PATCH] fs: implement cdev_mount()

[Ahmad Fatoum]

EFI loaders provide both block device and file system access to software
running under it. For file system access, we will just want to get a
mount if available and mount at a default location if not. Provide a
helper that does just that.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 fs/fs.c      | 19 +++++++++++++++++++
 include/fs.h |  1 +
 2 files changed, 20 insertions(+)

diff --git a/fs/fs.c b/fs/fs.c
index 78878e7112d5..a314a49b2db7 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -999,6 +999,25 @@ const char *cdev_mount_default(struct cdev *cdev, const char *fsoptions)
 	return cdev_get_mount_path(cdev);
 }
 
+/*
+ * cdev_mount - return existing mount or mount a cdev to the default path
+ *
+ * If a cdev is already mounted anywhere return the path
+ * it's mounted on.
+ * Otherwise mount it to /mnt/<cdevname> and return the path. Returns an
+ * error pointer on failure.
+ */
+const char *cdev_mount(struct cdev *cdev)
+{
+	const char *path;
+
+	path = cdev_get_mount_path(cdev);
+	if (path)
+		return path;
+
+	return cdev_mount_default(cdev, NULL);
+}
+
 /*
  * mount_all - iterate over block devices and mount all devices we are able to
  */
diff --git a/include/fs.h b/include/fs.h
index 894cae3e4c2f..9ea522dc2cc3 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -164,6 +164,7 @@ int fs_init_legacy(struct fs_device_d *fsdev);
 int fsdev_open_cdev(struct fs_device_d *fsdev);
 const char *cdev_get_mount_path(struct cdev *cdev);
 const char *cdev_mount_default(struct cdev *cdev, const char *fsoptions);
+const char *cdev_mount(struct cdev *cdev);
 void mount_all(void);
 
 void fsdev_set_linux_rootarg(struct fs_device_d *fsdev, const char *str);
-- 
2.30.2