block: update sysfs documentation

Add the description of the zoned, nr_zones and chunk_sectors sysfs queue
attributes to Documentation/block/queue-sysfs.txt. The description of
the zoned and chunk_sector attributes are mostly copied from
ABI/testing/sysfs-block (added a typo fix). While at it, also fix a
typo in the description of the io_poll_delay attribute.

nr_zones description is also added to ABI/testing/sysfs-block and
contact email address updated for the zoned attribute.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 28 insertions, 1 deletions

diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
index 2c1e67058fd3..39e286d7afc9 100644
--- a/Documentation/block/queue-sysfs.txt
+++ b/Documentation/block/queue-sysfs.txt
@@ -64,7 +64,7 @@ guess, the kernel will put the process issuing IO to sleep for an amount
 of time, before entering a classic poll loop. This mode might be a
 little slower than pure classic polling, but it will be more efficient.
 If set to a value larger than 0, the kernel will put the process issuing
-IO to sleep for this amont of microseconds before entering classic
+IO to sleep for this amount of microseconds before entering classic
 polling.
 
 iostats (RW)
@@ -194,4 +194,31 @@ blk-throttle makes decision based on the samplings. Lower time means cgroups
 have more smooth throughput, but higher CPU overhead. This exists only when
 CONFIG_BLK_DEV_THROTTLING_LOW is enabled.
 
+zoned (RO)
+----------
+This 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".
+
+nr_zones (RO)
+-------------
+For zoned block devices (zoned attribute indicating "host-managed" or
+"host-aware"), this indicates the total number of zones of the device.
+This is always 0 for regular block devices.
+
+chunk_sectors (RO)
+------------------
+This has different meaning depending on the type of the block device.
+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 in 512B sectors of the zones
+of the device, with the eventual exception of the last zone of the device which
+may be smaller.
+
 Jens Axboe <jens.axboe@oracle.com>, February 2009