From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Date: Mon, 01 Jul 2019 07:43:06 +0000 Subject: Re: [PATCH v3 02/11] s390x/mm: Fail when an altmap is used for arch_add_memory() Message-Id: <20190701074306.GC6376@dhcp22.suse.cz> List-Id: References: <20190527111152.16324-1-david@redhat.com> <20190527111152.16324-3-david@redhat.com> In-Reply-To: <20190527111152.16324-3-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: David Hildenbrand Cc: Oscar Salvador , linux-s390@vger.kernel.org, linux-ia64@vger.kernel.org, Vasily Gorbik , linux-sh@vger.kernel.org, Heiko Carstens , linux-kernel@vger.kernel.org, Wei Yang , linux-mm@kvack.org, Mike Rapoport , Martin Schwidefsky , Igor Mammedov , akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, Dan Williams , linux-arm-kernel@lists.infradead.org On Mon 27-05-19 13:11:43, David Hildenbrand wrote: > ZONE_DEVICE is not yet supported, fail if an altmap is passed, so we > don't forget arch_add_memory()/arch_remove_memory() when unlocking > support. Why do we need this? Sure ZONE_DEVICE is not supported for s390 and so might be the case for other arches which support hotplug. I do not see much point in adding warning to each of them. > Cc: Martin Schwidefsky > Cc: Heiko Carstens > Cc: Andrew Morton > Cc: Michal Hocko > Cc: Mike Rapoport > Cc: David Hildenbrand > Cc: Vasily Gorbik > Cc: Oscar Salvador > Suggested-by: Dan Williams > Signed-off-by: David Hildenbrand > --- > arch/s390/mm/init.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c > index 14d1eae9fe43..d552e330fbcc 100644 > --- a/arch/s390/mm/init.c > +++ b/arch/s390/mm/init.c > @@ -226,6 +226,9 @@ int arch_add_memory(int nid, u64 start, u64 size, > unsigned long size_pages = PFN_DOWN(size); > int rc; > > + if (WARN_ON_ONCE(restrictions->altmap)) > + return -EINVAL; > + > rc = vmem_add_mapping(start, size); > if (rc) > return rc; > -- > 2.20.1 > -- Michal Hocko SUSE Labs