Date: Sat, 12 Oct 2013 09:02:39 +0800
From: Shaohua Li <shli@kernel.org>
To: Kent Overstreet <kmo@daterainc.com>
Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk
Subject: Re: [patch 3/4] percpu_ida: add an API to return free tags
Message-ID: <20131012010239.GC17666@kernel.org>
References: <20131011071802.148101321@kernel.org>
 <20131011072341.346343362@kernel.org>
 <20131011203536.GJ28572@kmo>
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On Fri, Oct 11, 2013 at 01:35:36PM -0700, Kent Overstreet wrote:
> On Fri, Oct 11, 2013 at 03:18:05PM +0800, Shaohua Li wrote:
> > add an API to return free tags, blk-mq-tag will use it
> 
> Can you explain how this is going to be used? Seems like something that
> could be prone to misuse, try and convince me there isn't a better way
> to do what it's for.

There are two usages. One is for sysfs info output, which can be used for
diagnosis. The other one is blk-mq wants to determine if it's possible a
request can be queued. Neither requires precise data. Yes, caller should be
aware returned data isn't very precise.

Thanks,
Shaohua
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