From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jason Gunthorpe <jgg@ziepe.ca>
Subject: Re: [PATCH] IB/mad: Use ID allocator routines to allocate agent
 number
Date: Wed, 30 May 2018 16:09:34 -0600
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To: =?utf-8?B?SMOla29u?= Bugge <haakon.bugge@oracle.com>
Cc: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>, jackm <jackm@dev.mellanox.co.il>, Doug Ledford <dledford@redhat.com>, Daniel Jurgens <danielj@mellanox.com>, Parav Pandit <parav@mellanox.com>, Pravin Shedge <pravin.shedge4linux@gmail.com>, OFED mailing list <linux-rdma@vger.kernel.org>, linux-kernel@vger.kernel.org, Leon Romanovsky <leon@kernel.org>
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On Wed, May 30, 2018 at 10:07:16PM +0200, Håkon Bugge wrote:
> 
> 
> > On 30 May 2018, at 17:10, Jason Gunthorpe <jgg@ziepe.ca> wrote:
> > 
> > On Wed, May 30, 2018 at 02:22:56PM +0200, Hans Westgaard Ry wrote:
> > 
> >> We came up with this code snippet which we think handles both preventing
> >> immediate re-use and too big/wrapping...
> > 
> > Isn't this basically the same as idr_alloc_cyclic ?
> 
> I draw my statement back. The idr_alloc_cyclic() is the family of idr's that associates a pointer with the bit. Hence, each bit is a bit + 64b.
> 
> That's why we ended up with Hans' pseudo code.

Okay, fair enough.

Is it worth adding a ida_get_new_cyclic for this?

Jason