From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?Q?H=C3=A5kon_Bugge?= Subject: Re: [PATCH] IB/mad: Use ID allocator routines to allocate agent number Date: Tue, 29 May 2018 18:16:14 +0200 Message-ID: References: <20180529073808.27735-1-hans.westgaard.ry@oracle.com> <20180529154922.GA18457@ziepe.ca> Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20180529154922.GA18457@ziepe.ca> Sender: linux-kernel-owner@vger.kernel.org To: Jason Gunthorpe Cc: Hans Westgaard Ry , Doug Ledford , Jack Morgenstein , Daniel Jurgens , Parav Pandit , Pravin Shedge , OFED mailing list , linux-kernel@vger.kernel.org List-Id: linux-rdma@vger.kernel.org > On 29 May 2018, at 17:49, Jason Gunthorpe wrote: >=20 > On Tue, May 29, 2018 at 09:38:08AM +0200, Hans Westgaard Ry wrote: >> The agent TID is a 64 bit value split in two dwords. The least >> significant dword is the TID running counter. The most significant >> dword is the agent number. In the CX-3 shared port model, the mlx4 >> driver uses the most significant byte of the agent number to store = the >> slave number, making agent numbers greater and equal to 2^24 (3 = bytes) >> unusable. >=20 > There is no reason for this to be an ida, just do something like >=20 > mad_agent_priv->agent.hi_tid =3D atomic_inc_return(&ib_mad_client_id) = & mad_agent_priv->ib_dev->tid_mask; >=20 > And have the driver set tid_mask to 3 bytes of 0xFF The issue is that some of the mad agents are long-lived, so you will = wrap and use the same TID twice. Thxs, H=C3=A5kon >=20 > And no sysctl. >=20 > Jason > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" = in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html