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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 14 Aug 2018 13:44:43 -0400 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7EHigC78585736 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 14 Aug 2018 17:44:42 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 08D89B2068; Tue, 14 Aug 2018 13:43:58 -0400 (EDT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF0A3B2064; Tue, 14 Aug 2018 13:43:57 -0400 (EDT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.159]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 14 Aug 2018 13:43:57 -0400 (EDT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 1CF5916C2EBE; Tue, 14 Aug 2018 10:44:43 -0700 (PDT) Date: Tue, 14 Aug 2018 10:44:43 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: joel@joelfernandes.org, mathieu.desnoyers@efficios.com, peterz@infradead.org, tj@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] Make call_srcu() available during very early boot Reply-To: paulmck@linux.vnet.ibm.com References: <20180814162448.GA20414@linux.vnet.ibm.com> <20180814124945.5cf1753f@gandalf.local.home> <20180814170618.GA24813@linux.vnet.ibm.com> <20180814132453.093a4921@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180814132453.093a4921@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18081417-0052-0000-0000-0000031EF0C5 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009544; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01073483; UDB=6.00553122; IPR=6.00853441; MB=3.00022715; MTD=3.00000008; XFM=3.00000015; UTC=2018-08-14 17:44:45 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18081417-0053-0000-0000-00005DB997C2 Message-Id: <20180814174443.GG24813@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-14_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=878 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808140182 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 14, 2018 at 01:24:53PM -0400, Steven Rostedt wrote: > On Tue, 14 Aug 2018 10:06:18 -0700 > "Paul E. McKenney" wrote: > > > > > > #define __SRCU_STRUCT_INIT(name, pcpu_name) \ > > > > - { \ > > > > - .sda = &pcpu_name, \ > > > > - .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ > > > > - .srcu_gp_seq_needed = 0 - 1, \ > > > > - __SRCU_DEP_MAP_INIT(name) \ > > > > - } > > > > +{ \ > > > > + .sda = &pcpu_name, \ > > > > + .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ > > > > + .srcu_gp_seq_needed = 0 - 1, \ > > > > > > Interesting initialization of -1. This was there before, but still > > > interesting none the less. > > > > If I recall correctly, this subterfuge suppresses compiler complaints > > about initializing an unsigned long with a negative number. :-/ > > Did you try: > > .srcu_gp_seq_needed = -1UL, > > ? Works for my compiler, not sure what set of complaints pushed me in that direction. Thanx, Paul