Date: Tue, 15 Nov 2016 08:47:03 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@infradead.org>, keescook@chromium.org,
        will.deacon@arm.com, elena.reshetova@intel.com, arnd@arndb.de,
        tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com, dave@progbits.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 2/7] kref: Add kref_read()
Message-ID: <20161115074703.GK3142@twins.programming.kicks-ass.net>
References: <20161114173946.501528675@infradead.org>
 <20161114174446.486581399@infradead.org>
 <20161114181655.GA21516@infradead.org>
 <20161115072855.GB28248@kroah.com>
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On Tue, Nov 15, 2016 at 08:28:55AM +0100, Greg KH wrote:
> On Mon, Nov 14, 2016 at 10:16:55AM -0800, Christoph Hellwig wrote:
> > On Mon, Nov 14, 2016 at 06:39:48PM +0100, Peter Zijlstra wrote:
> > > Since we need to change the implementation, stop exposing internals.
> > > 
> > > Provide kref_read() to read the current reference count; typically
> > > used for debug messages.
> > 
> > Can we just provide a printk specifier for a kref value instead as
> > that is the only valid use case for reading the value?
> 
> Yeah, that would be great as no one should be doing anything
> logic-related based on the kref value.

IIRC there are a few users that WARN_ON() the value with a minimum bound
or somesuch. Those would be left in the cold, but yes I too like the
idea of a printk() format specifier.