[PATCH 02/13] Create a unique cdev number for on demand devices

[Juergen Beisert]

For disk like devices attached to MCI, ATA or USB it depends on the order they
will be recognized. So an unique number for all disk like devices is required.

Signed-off-by: Juergen Beisert <jbe at pengutronix.de>
---
 fs/devfs-core.c  |   14 ++++++++++++++
 include/driver.h |    1 +
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index 519e18e..89704b1 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -40,6 +40,20 @@ struct cdev *cdev_by_name(const char *filename)
 	return NULL;
 }
 
+int cdev_find_free_number(const char *basename)
+{
+	int i;
+	char fname[100];
+
+	for (i = 0; i < 1000; i++) {
+		snprintf(fname, sizeof(fname), "%s%d", basename, i);
+		if (cdev_by_name(fname) == NULL)
+			return i;
+	}
+
+	return -1;
+}
+
 struct cdev *cdev_open(const char *name, unsigned long flags)
 {
 	struct cdev *cdev = cdev_by_name(name);
diff --git a/include/driver.h b/include/driver.h
index 80de0c8..99b33d0 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -394,6 +394,7 @@ struct cdev {
 
 int devfs_create(struct cdev *);
 int devfs_remove(struct cdev *);
+int cdev_find_free_number(const char *);
 struct cdev *cdev_by_name(const char *filename);
 struct cdev *cdev_open(const char *name, unsigned long flags);
 void cdev_close(struct cdev *cdev);
-- 
1.7.7.1