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Feature #12969

SES driver could set device id and serial-number properties

Added by Garrett D'Amore 3 months ago. Updated 3 months ago.

Status:
In Progress
Priority:
Normal
Category:
kernel
Start date:
Due date:
% Done:

90%

Estimated time:
Difficulty:
Medium
Tags:
Gerrit CR:

Description

In real configurations, SCSI enclosures (SAS devices usually, but not always) are often on multiple paths to the initiator.

It can be somewhat more work for user space applications or even end-users to correlate multiple /dev/es/sesXX nodes. This is worse when there are multiple enclosures present as well.

There are two things that would help here.

First the inquiry-serial-no property should probably be populated from VPD page 0x80 when it is available.

Second, the driver should probably also create a device id (libdevid) when either pages 0x83 or 0x80 are present, using the same approach used by the sd driver. The device ID, when present, uniquely identifies the LUN in question, and is the very best authoritative solution to determine whether two /dev/es/sesXX nodes refer to the same device or not.

Note that I am also planning to submit changes to better support mxpio with SES devices, which will also help, but I believe the changes requested here stand alone (if in support of) that, and will still be useful in circumstances when mpxio cannot be used. It also helps user applications determine (for display usually) the serial number without requiring them to issue low level SCSI inquiries on their own.

#1

Updated by Garrett D'Amore 3 months ago

  • Subject changed from SES driver could populate both device id and inquiry-serial-number properties to SES driver could set device id and inquiry-serial-number properties
#2

Updated by Garrett D'Amore 3 months ago

  • Subject changed from SES driver could set device id and inquiry-serial-number properties to SES driver could set device id and serial-number properties
#3

Updated by Electric Monk 3 months ago

  • Gerrit CR set to 806

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