linux-kernel - Re: [PATCH 01/13] seqnum_ops: Introduce Sequence Number Ops

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Message-ID: <X6r7Vl45bgGQiAD2@kroah.com>
Date:   Tue, 10 Nov 2020 21:43:02 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Shuah Khan <skhan@...uxfoundation.org>
Cc:     corbet@....net, keescook@...omium.org, peterz@...radead.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/13] seqnum_ops: Introduce Sequence Number Ops

On Tue, Nov 10, 2020 at 09:41:40PM +0100, Greg KH wrote:
> On Tue, Nov 10, 2020 at 12:53:27PM -0700, Shuah Khan wrote:
> > +Decrement interface
> > +-------------------
> > +
> > +Decrements sequence number and doesn't return the new value. ::
> > +
> > +        seqnum32_dec() --> atomic_dec()
> > +        seqnum64_dec() --> atomic64_dec()
> 
> Why would you need to decrement a sequence number?  Shouldn't they just
> always go up?
> 
> I see you use them in your patch 12/13, but I don't think that really is
> a sequence number there, but rather just some other odd value :)

Note, other than this, I like the idea.  It makes it obvious what these
atomic variables are being used for, and they can't be abused for other
things.  Nice work.

thanks,

greg k-h