UBI: add UBI devices reference counting
This is one more step on the way to "removable" UBI devices. It
adds reference counting for UBI devices. Every time a volume on
this device is opened - the device's refcount is increased. It
is also increased if someone is reading any sysfs file of this
UBI device or of one of its volumes.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index bc900d2..01978b5 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -56,23 +56,6 @@
#endif
/**
- * major_to_device - get UBI device object by character device major number.
- * @major: major number
- *
- * This function returns a pointer to the UBI device object.
- */
-static struct ubi_device *major_to_device(int major)
-{
- int i;
-
- for (i = 0; i < UBI_MAX_DEVICES; i++)
- if (ubi_devices[i] && MAJOR(ubi_devices[i]->cdev.dev) == major)
- return ubi_devices[i];
- BUG();
- return NULL;
-}
-
-/**
* get_exclusive - get exclusive access to an UBI volume.
* @desc: volume descriptor
*
@@ -129,9 +112,11 @@
static int vol_cdev_open(struct inode *inode, struct file *file)
{
struct ubi_volume_desc *desc;
- const struct ubi_device *ubi = major_to_device(imajor(inode));
- int vol_id = iminor(inode) - 1;
- int mode;
+ int vol_id = iminor(inode) - 1, mode, ubi_num;
+
+ ubi_num = ubi_major2num(imajor(inode));
+ if (ubi_num < 0)
+ return ubi_num;
if (file->f_mode & FMODE_WRITE)
mode = UBI_READWRITE;
@@ -140,7 +125,7 @@
dbg_msg("open volume %d, mode %d", vol_id, mode);
- desc = ubi_open_volume(ubi->ubi_num, vol_id, mode);
+ desc = ubi_open_volume(ubi_num, vol_id, mode);
if (IS_ERR(desc))
return PTR_ERR(desc);
@@ -586,9 +571,9 @@
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
- ubi = major_to_device(imajor(inode));
- if (IS_ERR(ubi))
- return PTR_ERR(ubi);
+ ubi = ubi_get_by_major(imajor(inode));
+ if (!ubi)
+ return -ENODEV;
switch (cmd) {
/* Create volume command */
@@ -695,6 +680,7 @@
break;
}
+ ubi_put_device(ubi);
return err;
}
