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Subject: Re: [PATCH] IB/mad: Use ID allocator routines to allocate agent
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From:   =?utf-8?Q?H=C3=A5kon_Bugge?= <haakon.bugge@oracle.com>
In-Reply-To: <20180530220934.GI30754@ziepe.ca>
Date:   Thu, 31 May 2018 21:54:40 +0200
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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To:     Jason Gunthorpe <jgg@ziepe.ca>
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> On 31 May 2018, at 00:09, Jason Gunthorpe <jgg@ziepe.ca> wrote:
>=20
> On Wed, May 30, 2018 at 10:07:16PM +0200, H=C3=A5kon Bugge wrote:
>>=20
>>=20
>>> On 30 May 2018, at 17:10, Jason Gunthorpe <jgg@ziepe.ca> wrote:
>>>=20
>>> On Wed, May 30, 2018 at 02:22:56PM +0200, Hans Westgaard Ry wrote:
>>>=20
>>>> We came up with this code snippet which we think handles both =
preventing
>>>> immediate re-use and too big/wrapping...
>>>=20
>>> Isn't this basically the same as idr_alloc_cyclic ?
>>=20
>> 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.
>>=20
>> That's why we ended up with Hans' pseudo code.
>=20
> Okay, fair enough.
>=20
> Is it worth adding a ida_get_new_cyclic for this?

My initial reaction was "no", but then I found the same cyclic behaviour =
in drivers/net/ipvlan/ipvlan_main.c

Then in my opinion, it makes sense to create a ida_simple_get_cyclic()


Thxs, H=C3=A5kon