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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 3 Dec 2018 16:49:26 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wB3GnQwc49283140 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 3 Dec 2018 16:49:26 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E1FE2A405D; Mon, 3 Dec 2018 16:49:25 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 77C2AA4040; Mon, 3 Dec 2018 16:49:23 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.206.196]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 3 Dec 2018 16:49:23 +0000 (GMT) Date: Mon, 3 Dec 2018 18:49:21 +0200 From: Mike Rapoport To: Sam Ravnborg Subject: Re: [PATCH v2 5/6] arch: simplify several early memory allocations References: <1543852035-26634-1-git-send-email-rppt@linux.ibm.com> <1543852035-26634-6-git-send-email-rppt@linux.ibm.com> <20181203162908.GB4244@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181203162908.GB4244@ravnborg.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 18120316-0028-0000-0000-000003256787 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18120316-0029-0000-0000-000023E16C79 Message-Id: <20181203164920.GB26700@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-12-03_09:, , 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812030157 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Hocko , linux-sh@vger.kernel.org, linux-mm@kvack.org, Rich Felker , Paul Mackerras , sparclinux@vger.kernel.org, Vincent Chen , Jonas Bonn , linux-c6x-dev@linux-c6x.org, Yoshinori Sato , Russell King , Mark Salter , Arnd Bergmann , Stefan Kristiansson , openrisc@lists.librecores.org, Greentime Hu , Stafford Horne , Guan Xuetao , linux-arm-kernel@lists.infradead.org, Michal Simek , linux-kernel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Dec 03, 2018 at 05:29:08PM +0100, Sam Ravnborg wrote: > Hi Mike. > > > index c37955d..2a17665 100644 > > --- a/arch/sparc/kernel/prom_64.c > > +++ b/arch/sparc/kernel/prom_64.c > > @@ -34,16 +34,13 @@ > > > > void * __init prom_early_alloc(unsigned long size) > > { > > - unsigned long paddr = memblock_phys_alloc(size, SMP_CACHE_BYTES); > > - void *ret; > > + void *ret = memblock_alloc(size, SMP_CACHE_BYTES); > > > > - if (!paddr) { > > + if (!ret) { > > prom_printf("prom_early_alloc(%lu) failed\n", size); > > prom_halt(); > > } > > > > - ret = __va(paddr); > > - memset(ret, 0, size); > > prom_early_allocated += size; > > > > return ret; > > memblock_alloc() calls memblock_alloc_try_nid(). > And if allocation fails then memblock_alloc_try_nid() calls panic(). > So will we ever hit the prom_halt() code? memblock_phys_alloc_try_nid() also calls panic if an allocation fails. So in either case we never reach prom_halt() code. Actually, sparc is rather an exception from the general practice to rely on panic() inside the early allocator rather than to check the return value. > Do we have a panic() implementation that actually returns? > > > > diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c > > index 3c8aac2..52884f4 100644 > > --- a/arch/sparc/mm/init_64.c > > +++ b/arch/sparc/mm/init_64.c > > @@ -1089,16 +1089,13 @@ static void __init allocate_node_data(int nid) > > struct pglist_data *p; > > unsigned long start_pfn, end_pfn; > > #ifdef CONFIG_NEED_MULTIPLE_NODES > > - unsigned long paddr; > > > > - paddr = memblock_phys_alloc_try_nid(sizeof(struct pglist_data), > > - SMP_CACHE_BYTES, nid); > > - if (!paddr) { > > + NODE_DATA(nid) = memblock_alloc_node(sizeof(struct pglist_data), > > + SMP_CACHE_BYTES, nid); > > + if (!NODE_DATA(nid)) { > > prom_printf("Cannot allocate pglist_data for nid[%d]\n", nid); > > prom_halt(); > > } > > - NODE_DATA(nid) = __va(paddr); > > - memset(NODE_DATA(nid), 0, sizeof(struct pglist_data)); > > > > NODE_DATA(nid)->node_id = nid; > > #endif > > Same here. > > I did not look at the other cases. I really tried to be careful and did the replacements only for the calls that do panic if an allocation fails. > Sam > -- Sincerely yours, Mike.