Re: [PATCH v9 0/5] Initial support for multi-actuator HDDs

On 10/26/21 8:22 PM, Damien Le Moal wrote:

From: Damien Le Moal <redacted>

Single LUN multi-actuator hard-disks are cappable to seek and execute
multiple commands in parallel. This capability is exposed to the host
using the Concurrent Positioning Ranges VPD page (SCSI) and Log (ATA).
Each positioning range describes the contiguous set of LBAs that an
actuator serves.

This series adds support to the scsi disk driver to retreive this
information and advertize it to user space through sysfs. libata is
also modified to handle ATA drives.

The first patch adds the block layer plumbing to expose concurrent
sector ranges of the device through sysfs as a sub-directory of the
device sysfs queue directory. Patch 2 and 3 add support to sd and
libata. Finally patch 4 documents the sysfs queue attributed changes.
Patch 5 fixes a typo in the document file (strictly speaking, not
related to this series).

This series does not attempt in any way to optimize accesses to
multi-actuator devices (e.g. block IO schedulers or filesystems). This
initial support only exposes the independent access ranges information
to user space through sysfs.

I've applied 1/9 for now, as that clearly belongs in the block tree.
Might be the cleanest if SCSI does a post tree that depends on
for-5.16/block. Or I can apply it all as they are reviewed. Let me
know.

-- 
Jens Axboe