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authorChaitanya Kulkarni <chaitanya.kulkarni@hgst.com>2016-11-30 23:28:59 +0300
committerJens Axboe <axboe@fb.com>2016-12-01 17:58:40 +0300
commita6f0788ec2881ac14e97ff7fa6a78a807f87b5ba (patch)
tree493bf4be078a224b84c405220965e7a6c00a505c /Documentation
parente73c23ff736e1ea371dfa419d7bf8e77ee53044a (diff)
downloadlinux-a6f0788ec2881ac14e97ff7fa6a78a807f87b5ba.tar.xz
block: add support for REQ_OP_WRITE_ZEROES
This adds a new block layer operation to zero out a range of LBAs. This allows to implement zeroing for devices that don't use either discard with a predictable zero pattern or WRITE SAME of zeroes. The prominent example of that is NVMe with the Write Zeroes command, but in the future, this should also help with improving the way zeroing discards work. For this operation, suitable entry is exported in sysfs which indicate the number of maximum bytes allowed in one write zeroes operation by the device. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-block13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index ee2d5cd26bfe..2da04ce6aeef 100644
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -235,6 +235,19 @@ 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>