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From: Damien Le Moal <>
To:, Jens Axboe <>,,
	"Martin K . Petersen" <>,
Subject: [PATCH 4/4] doc: document sysfs queue/cranges attributes
Date: Wed, 21 Jul 2021 19:42:05 +0900	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Update the file Documentation/block/queue-sysfs.rst to add a description
of a device queue sysfs entries related to concurrent sector ranges
(e.g. concurrent positioning ranges for multi-actuator hard-disks).

While at it, also fix a typo in this file introduction paragraph.

Signed-off-by: Damien Le Moal <>
 Documentation/block/queue-sysfs.rst | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 4dc7f0d499a8..ffbea0c7a576 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -4,7 +4,7 @@ Queue sysfs files
 This text file will detail the queue files that are located in the sysfs tree
 for each block device. Note that stacked devices typically do not export
-any settings, since their queue merely functions are a remapping target.
+any settings, since their queue merely functions as a remapping target.
 These files are the ones found in the /sys/block/xxx/queue/ directory.
 Files denoted with a RO postfix are readonly and the RW postfix means
@@ -286,4 +286,29 @@ sequential zones of zoned block devices (devices with a zoned attributed
 that reports "host-managed" or "host-aware"). This value is always 0 for
 regular block devices.
+cranges (RO)
+The presence of this sub-directory of the /sys/block/xxx/queue/ directory
+indicates that the device is capable of executing requests targeting
+different sector ranges in parallel. For instance, single LUN multi-actuator
+hard-disks will likely have a cranges directory if the device correctly
+advertizes the sector ranges of its actuators.
+The cranges directory contains one directory per sector range, with each
+range described using the sector (RO) attribute file to indicate the first
+sector of the range and the nr_sectors (RO) attribute file to indicate the
+total number of sector in the range starting from the first sector.
+For example, a dual-actuator hard disk will have the following cranges
+        $ tree /sys/block/<device>/queue/cranges/
+        /sys/block/<device>/queue/cranges/
+        |-- 0
+        |   |-- nr_sectors
+        |   `-- sector
+        `-- 1
+            |-- nr_sectors
+            `-- sector
 Jens Axboe <>, February 2009

  parent reply	other threads:[~2021-07-21 11:33 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-21 10:42 [PATCH 0/4] Initial support for multi-actuator HDDs Damien Le Moal
2021-07-21 10:42 ` [PATCH 1/4] block: Add concurrent positioning ranges support Damien Le Moal
2021-07-22 16:11   ` Hannes Reinecke
2021-07-22 23:20     ` Damien Le Moal
2021-07-22 23:59     ` Damien Le Moal
2021-07-21 10:42 ` [PATCH 2/4] scsi: sd: add " Damien Le Moal
2021-07-21 18:01   ` Dan Carpenter
2021-07-22 16:14   ` Hannes Reinecke
2021-07-22 23:26     ` Damien Le Moal
2021-07-21 10:42 ` [PATCH 3/4] libata: support concurrent positioning ranges log Damien Le Moal
2021-07-22 17:34   ` Hannes Reinecke
2021-07-22 23:27     ` Damien Le Moal
2021-07-21 10:42 ` Damien Le Moal [this message]
2021-07-22 15:58 ` [PATCH 0/4] Initial support for multi-actuator HDDs Hannes Reinecke

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