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UBI: add UBI devices reference counting

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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>
This commit is contained in:
Artem Bityutskiy
2007-12-17 17:37:26 +02:00
parent 9f961b5756
commit e73f4459d9
7 changed files with 201 additions and 63 deletions
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59
drivers/mtd/ubi/kapi.c
View File

@@ -30,23 +30,27 @@
* @ubi_num: UBI device number
* @di: the information is stored here
*
* This function returns %0 in case of success and a %-ENODEV if there is no
* such UBI device.
* This function returns %0 in case of success, %-EINVAL if the UBI device
* number is invalid, and %-ENODEV if there is no such UBI device.
*/
int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
{
const struct ubi_device *ubi;
struct ubi_device *ubi;
if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES ||
!ubi_devices[ubi_num])
if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
return -EINVAL;
ubi = ubi_get_device(ubi_num);
if (!ubi)
return -ENODEV;
ubi = ubi_devices[ubi_num];
di->ubi_num = ubi->ubi_num;
di->leb_size = ubi->leb_size;
di->min_io_size = ubi->min_io_size;
di->ro_mode = ubi->ro_mode;
di->cdev = ubi->cdev.dev;
ubi_put_device(ubi);
return 0;
}
EXPORT_SYMBOL_GPL(ubi_get_device_info);
@@ -111,16 +115,23 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
mode != UBI_EXCLUSIVE)
return ERR_PTR(-EINVAL);
ubi = ubi_devices[ubi_num];
/*
* First of all, we have to get the UBI device to prevent its removal.
*/
ubi = ubi_get_device(ubi_num);
if (!ubi)
return ERR_PTR(-ENODEV);
if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
return ERR_PTR(-EINVAL);
if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
err = -EINVAL;
goto out_put_ubi;
}
desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
if (!desc)
return ERR_PTR(-ENOMEM);
if (!desc) {
err = -ENOMEM;
goto out_put_ubi;
}
err = -ENODEV;
if (!try_module_get(THIS_MODULE))
@@ -188,6 +199,8 @@ out_unlock:
module_put(THIS_MODULE);
out_free:
kfree(desc);
out_put_ubi:
ubi_put_device(ubi);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(ubi_open_volume);
@@ -205,6 +218,7 @@ struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
{
int i, vol_id = -1, len;
struct ubi_device *ubi;
struct ubi_volume_desc *ret;
dbg_msg("open volume %s, mode %d", name, mode);
@@ -218,7 +232,7 @@ struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
return ERR_PTR(-EINVAL);
ubi = ubi_devices[ubi_num];
ubi = ubi_get_device(ubi_num);
if (!ubi)
return ERR_PTR(-ENODEV);
@@ -234,10 +248,17 @@ struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
}
spin_unlock(&ubi->volumes_lock);
if (vol_id < 0)
return ERR_PTR(-ENODEV);
if (vol_id >= 0)
ret = ubi_open_volume(ubi_num, vol_id, mode);
else
ret = ERR_PTR(-ENODEV);
return ubi_open_volume(ubi_num, vol_id, mode);
/*
* We should put the UBI device even in case of success, because
* 'ubi_open_volume()' took a reference as well.
*/
ubi_put_device(ubi);
return ret;
}
EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
@@ -248,10 +269,11 @@ EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
void ubi_close_volume(struct ubi_volume_desc *desc)
{
struct ubi_volume *vol = desc->vol;
struct ubi_device *ubi = vol->ubi;
dbg_msg("close volume %d, mode %d", vol->vol_id, desc->mode);
spin_lock(&vol->ubi->volumes_lock);
spin_lock(&ubi->volumes_lock);
switch (desc->mode) {
case UBI_READONLY:
vol->readers -= 1;
@@ -263,10 +285,11 @@ void ubi_close_volume(struct ubi_volume_desc *desc)
vol->exclusive = 0;
}
vol->ref_count -= 1;
spin_unlock(&vol->ubi->volumes_lock);
spin_unlock(&ubi->volumes_lock);
put_device(&vol->dev);
kfree(desc);
put_device(&vol->dev);
ubi_put_device(ubi);
module_put(THIS_MODULE);
}
EXPORT_SYMBOL_GPL(ubi_close_volume);