Re: [PATCH v8 2/5] scsi: sd: add concurrent positioning ranges support

On 9/9/21 4:35 AM, Damien Le Moal wrote:

Add the sd_read_cpr() function to the sd scsi disk driver to discover
if a device has multiple concurrent positioning ranges (i.e. multiple
actuators on an HDD). The existence of VPD page B9h indicates if a
device has multiple concurrent positioning ranges. The page content
describes each range supported by the device.

sd_read_cpr() is called from sd_revalidate_disk() and uses the block
layer functions disk_alloc_independent_access_ranges() and
disk_set_independent_access_ranges() to represent the set of actuators
of the device as independent access ranges.

The format of the Concurrent Positioning Ranges VPD page B9h is defined
in section 6.6.6 of SBC-5.

Signed-off-by: Damien Le Moal <redacted>
---
  drivers/scsi/sd.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++
  drivers/scsi/sd.h |  1 +
  2 files changed, 82 insertions(+)

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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