[dm-devel] [PATCH 2/2] dm-mpath: Remove useless retain_attached_hw_handler parameter

[Mike Snitzer]

On Thu, Nov 24 2016 at  2:11am -0500,
tang.junhui at zte.com.cn <tang.junhui at zte.com.cn> wrote:

> From: "tang.junhui" <tang.junhui at zte.com.cn>
> 
> Hardware handle would be retained no matter parameter
> retain_attached_hw_handler is set or not in the logic
> of current code. So remove this useless parameter.

Right, that wasn't always the case.  Previously (before commit )
dm-mpath would first detach the attached handler.

I'm not completely opposed to removing the code that checks
MPATHF_RETAIN_ATTACHED_HW_HANDLER in parse_path() but your proposed
patch is broken in 2 ways:
1) in parse_path() you need to always initialize q
2) setting m->hw_handler_name to attached_handler_name needs to still
   happen regardless of whether m->hw_handler_name was previously set
3) the "retain_attached_hw_handler" feature should still be allowed on
   the command line, no sense to break multipath-tools

But honestly, I'm not seeing any reason to not just leave the existing
code.