From 28b841b3a7cb07a4bfd436a15b31bc88509dcf9a Mon Sep 17 00:00:00 2001 From: Jan Höppner Date: Thu, 30 Jun 2016 13:28:57 +0200 Subject: s390/dasd: Add discard support for FBA devices MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The z/VM hypervisor provides virtual disks (VDISK) which are backed by main memory of the hypervisor. Those devices are seen as DASD FBA disks within the Linux guest. Whenever data is written to such a device, memory is allocated on-the-fly by z/VM accordingly. This memory, however, is not being freed if data on the device is deleted by the guest OS. In order to make memory usable after deletion again, add discard support to the FBA discipline. While at it, update comments regarding the DASD_FEATURE_* flags. Reviewed-by: Stefan Haberland Signed-off-by: Jan Höppner Signed-off-by: Martin Schwidefsky --- drivers/s390/block/dasd_devmap.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/s390/block/dasd_devmap.c') diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c index 7b539d92eeaf..e38042ce94e6 100644 --- a/drivers/s390/block/dasd_devmap.c +++ b/drivers/s390/block/dasd_devmap.c @@ -1676,6 +1676,7 @@ dasd_set_feature(struct ccw_device *cdev, int feature, int flag) spin_unlock(&dasd_devmap_lock); return 0; } +EXPORT_SYMBOL(dasd_set_feature); int -- cgit