block: add support for REQ_OP_WRITE_ZEROES

[mirror_ubuntu-bionic-kernel.git] / Documentation / ABI / testing / sysfs-block

diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index 71d184dbb70d29daabf9ad1461d12615c7d34fbf..2da04ce6aeef482645bfd9edd924ce195275ea26 100644 (file)
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -235,3 +235,45 @@ Description:
                write_same_max_bytes is 0, write same is not supported
                by the device.
 
+What:          /sys/block/<disk>/queue/write_zeroes_max_bytes
+Date:          November 2016
+Contact:       Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
+Description:
+               Devices that support write zeroes operation in which a
+               single request can be issued to zero out the range of
+               contiguous blocks on storage without having any payload
+               in the request. This can be used to optimize writing zeroes
+               to the devices. write_zeroes_max_bytes indicates how many
+               bytes can be written in a single write zeroes command. If
+               write_zeroes_max_bytes is 0, write zeroes is not supported
+               by the device.
+
+What:          /sys/block/<disk>/queue/zoned
+Date:          September 2016
+Contact:       Damien Le Moal <damien.lemoal@hgst.com>
+Description:
+               zoned indicates if the device is a zoned block device
+               and the zone model of the device if it is indeed zoned.
+               The possible values indicated by zoned are "none" for
+               regular block devices and "host-aware" or "host-managed"
+               for zoned block devices. The characteristics of
+               host-aware and host-managed zoned block devices are
+               described in the ZBC (Zoned Block Commands) and ZAC
+               (Zoned Device ATA Command Set) standards. These standards
+               also define the "drive-managed" zone model. However,
+               since drive-managed zoned block devices do not support
+               zone commands, they will be treated as regular block
+               devices and zoned will report "none".
+
+What:          /sys/block/<disk>/queue/chunk_sectors
+Date:          September 2016
+Contact:       Hannes Reinecke <hare@suse.com>
+Description:
+               chunk_sectors has different meaning depending on the type
+               of the disk. For a RAID device (dm-raid), chunk_sectors
+               indicates the size in 512B sectors of the RAID volume
+               stripe segment. For a zoned block device, either
+               host-aware or host-managed, chunk_sectors indicates the
+               size of 512B sectors of the zones of the device, with
+               the eventual exception of the last zone of the device
+               which may be smaller.