From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753157AbeDSC7x (ORCPT ); Wed, 18 Apr 2018 22:59:53 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:58408 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752792AbeDSC7v (ORCPT ); Wed, 18 Apr 2018 22:59:51 -0400 Subject: Re: [PATCH] IB/core: Make ib_mad_client_id atomic To: =?UTF-8?Q?H=c3=a5kon_Bugge?= , Doug Ledford , Don Hiatt , Dasaratharaman Chandramouli , Ira Weiny , Sean Hefty Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org References: <20180418142450.15581-1-Haakon.Bugge@oracle.com> From: Yanjun Zhu Organization: Oracle Corporation Message-ID: Date: Thu, 19 Apr 2018 10:59:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180418142450.15581-1-Haakon.Bugge@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8867 signatures=668698 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1804190027 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/4/18 22:24, Håkon Bugge wrote: > Two kernel threads may get the same value for agent.hi_tid, if the > agents are registered for different ports. As of now, this works, as > the agent list is per port. > > It is however confusing and not future robust. Hence, making it > atomic. > > Signed-off-by: Håkon Bugge > Reviewed-by: Jack Morgenstein Reviewed-by: Zhu Yanjun > --- > drivers/infiniband/core/mad.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c > index c50596f7f98a..b28452a55a08 100644 > --- a/drivers/infiniband/core/mad.c > +++ b/drivers/infiniband/core/mad.c > @@ -59,7 +59,7 @@ module_param_named(recv_queue_size, mad_recvq_size, int, 0444); > MODULE_PARM_DESC(recv_queue_size, "Size of receive queue in number of work requests"); > > static struct list_head ib_mad_port_list; > -static u32 ib_mad_client_id = 0; > +static atomic_t ib_mad_client_id = ATOMIC_INIT(0); > > /* Port list lock */ > static DEFINE_SPINLOCK(ib_mad_port_list_lock); > @@ -377,7 +377,7 @@ struct ib_mad_agent *ib_register_mad_agent(struct ib_device *device, > } > > spin_lock_irqsave(&port_priv->reg_lock, flags); > - mad_agent_priv->agent.hi_tid = ++ib_mad_client_id; > + mad_agent_priv->agent.hi_tid = atomic_inc_return(&ib_mad_client_id); > > /* > * Make sure MAD registration (if supplied)