aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/include/uapi
diff options
context:
space:
mode:
authorJan Höppner <hoeppner@linux.vnet.ibm.com>2016-06-30 11:28:57 (GMT)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-08-29 14:31:26 (GMT)
commit28b841b3a7cb07a4bfd436a15b31bc88509dcf9a (patch)
treeb73ad19e32e2be733c51419b7b859f7e900b4ced /arch/s390/include/uapi
parent8b94dd9e0d4439f83fcc55f1f8020c86e79b623d (diff)
s390/dasd: Add discard support for FBA devices
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 <sth@linux.vnet.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/uapi')
-rw-r--r--arch/s390/include/uapi/asm/dasd.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/s390/include/uapi/asm/dasd.h b/arch/s390/include/uapi/asm/dasd.h
index 1340311..ab5797c 100644
--- a/arch/s390/include/uapi/asm/dasd.h
+++ b/arch/s390/include/uapi/asm/dasd.h
@@ -72,7 +72,10 @@ typedef struct dasd_information2_t {
* 0x02: use diag discipline (diag)
* 0x04: set the device initially online (internal use only)
* 0x08: enable ERP related logging
- * 0x20: give access to raw eckd data
+ * 0x10: allow I/O to fail on lost paths
+ * 0x20: allow I/O to fail when a lock was stolen
+ * 0x40: give access to raw eckd data
+ * 0x80: enable discard support
*/
#define DASD_FEATURE_DEFAULT 0x00
#define DASD_FEATURE_READONLY 0x01
@@ -82,6 +85,7 @@ typedef struct dasd_information2_t {
#define DASD_FEATURE_FAILFAST 0x10
#define DASD_FEATURE_FAILONSLCK 0x20
#define DASD_FEATURE_USERAW 0x40
+#define DASD_FEATURE_DISCARD 0x80
#define DASD_PARTN_BITS 2

Privacy Policy