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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 /drivers/s390/block/dasd_int.h | |
| parent | 8b94dd9e0d4439f83fcc55f1f8020c86e79b623d (diff) | |
| download | linux-28b841b3a7cb07a4bfd436a15b31bc88509dcf9a.tar.bz2 | |
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 'drivers/s390/block/dasd_int.h')
| -rw-r--r-- | drivers/s390/block/dasd_int.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h index 66248795b973..f9e25fc03d6b 100644 --- a/drivers/s390/block/dasd_int.h +++ b/drivers/s390/block/dasd_int.h @@ -167,6 +167,9 @@ do { \ printk(d_loglevel PRINTK_HEADER " " d_string "\n", d_args); \ } while(0) +/* Macro to calculate number of blocks per page */ +#define BLOCKS_PER_PAGE(blksize) (PAGE_SIZE / blksize) + struct dasd_ccw_req { unsigned int magic; /* Eye catcher */ struct list_head devlist; /* for dasd_device request queue */ |