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| author | Jan Höppner <hoeppner@linux.vnet.ibm.com> | 2016-06-30 13:28:57 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-08-29 16:31:26 +0200 |
| commit | 28b841b3a7cb07a4bfd436a15b31bc88509dcf9a (patch) | |
| tree | b73ad19e32e2be733c51419b7b859f7e900b4ced /arch/s390 | |
| parent | s390/zcrypt: make CPRBX const (diff) | |
| download | linux-28b841b3a7cb07a4bfd436a15b31bc88509dcf9a.tar.xz linux-28b841b3a7cb07a4bfd436a15b31bc88509dcf9a.zip | |
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')
| -rw-r--r-- | arch/s390/include/uapi/asm/dasd.h | 6 |
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 1340311dab77..ab5797cdc1b7 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 |