Merge tag 'for-5.16/scsi-ma-2021-10-29' of git://git.kernel.dk/linux-block

Pull SCSI multi-actuator support from Jens Axboe:
 "This adds SCSI support for the recently merged block multi-actuator
  support. Since this was sitting on top of the block tree, the SCSI
  side asked me to queue it up."

* tag 'for-5.16/scsi-ma-2021-10-29' of git://git.kernel.dk/linux-block:
  doc: Fix typo in request queue sysfs documentation
  doc: document sysfs queue/independent_access_ranges attributes
  libata: support concurrent positioning ranges log
  scsi: sd: add concurrent positioning ranges support

1 files changed, 32 insertions, 1 deletions

diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 4dc7f0d499a8..e8c74306f70a 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 +286,35 @@ 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.
 
+independent_access_ranges (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 have an independent_access_ranges directory if the device
+correctly advertizes the sector ranges of its actuators.
+
+The independent_access_ranges directory contains one directory per access
+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 sectors in the range starting from the first
+sector of the range.  For example, a dual-actuator hard-disk will have the
+following independent_access_ranges entries.::
+
+        $ tree /sys/block/<device>/queue/independent_access_ranges/
+        /sys/block/<device>/queue/independent_access_ranges/
+        |-- 0
+        |   |-- nr_sectors
+        |   `-- sector
+        `-- 1
+            |-- nr_sectors
+            `-- sector
+
+The sector and nr_sectors attributes use 512B sector unit, regardless of
+the actual block size of the device. Independent access ranges do not
+overlap and include all sectors within the device capacity. The access
+ranges are numbered in increasing order of the range start sector,
+that is, the sector attribute of range 0 always has the value 0.
+
 Jens Axboe <jens.axboe@oracle.com>, February 2009