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 2b5d56127fce4d7f9a6f83b535cdfcf469f83e0b..279da08f754192c07ba10c47eb0a4ea8e8c95892 100644 (file)
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -206,16 +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>/alias
-Date:          Aug 2011
-Contact:       Nao Nishijima <nao.nishijima.xt@hitachi.com>
-Description:
-               A raw device name of a disk does not always point a same disk
-               each boot-up time. Therefore, users have to use persistent
-               device names, which udev creates when the kernel finds a disk,
-               instead of raw device name. However, kernel doesn't show those
-               persistent names on its messages (e.g. dmesg).
-               This file can store an alias of the disk and it would be
-               appeared in kernel messages if it is set. A disk can have an
-               alias which length is up to 255bytes. Users can use alphabets,
-               numbers, "-" and "_" in alias name. This file is writeonce.
+
+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.
+