block: Implement support for WRITE SAME

[firefly-linux-kernel-4.4.55.git] / Documentation / ABI / testing / sysfs-block

diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index c1eb41cb9876083d3df79a6a995b692762acd21b..279da08f754192c07ba10c47eb0a4ea8e8c95892 100644 (file)
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -206,3 +206,17 @@ Description:
                when a discarded area is read the discard_zeroes_data
                parameter will be set to one. Otherwise it will be 0 and
                the result of reading a discarded area is undefined.
+
+What:          /sys/block/<disk>/queue/write_same_max_bytes
+Date:          January 2012
+Contact:       Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+               Some devices support a write same operation in which a
+               single data block can be written to a range of several
+               contiguous blocks on storage. This can be used to wipe
+               areas on disk or to initialize drives in a RAID
+               configuration. write_same_max_bytes indicates how many
+               bytes can be written in a single write same command. If
+               write_same_max_bytes is 0, write same is not supported
+               by the device.
+