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Tsirkin" To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, Andrew Morton , Jason Wang , Alexey Dobriyan , Mike Rapoport , "Matthew Wilcox (Oracle)" , Oscar Salvador , Michal Hocko , Roman Gushchin , Alex Shi , Steven Price , Mike Kravetz , Aili Yao , Jiri Bohac , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , Naoya Horiguchi , linux-hyperv@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v1 6/7] virtio-mem: use page_offline_(start|end) when setting PageOffline() Message-ID: <20210503042220-mutt-send-email-mst@kernel.org> References: <20210429122519.15183-1-david@redhat.com> <20210429122519.15183-7-david@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210429122519.15183-7-david@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: D548740002DA X-Stat-Signature: m8hbthr7ukxgxdkhnnqeuump7ytwpw1r Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Fqv1CKmp; spf=none (imf10.hostedemail.com: domain of mst@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=mst@redhat.com; dmarc=pass (policy=none) header.from=redhat.com Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf10; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=216.205.24.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620030221-990410 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Apr 29, 2021 at 02:25:18PM +0200, David Hildenbrand wrote: > Let's properly use page_offline_(start|end) to synchronize setting > PageOffline(), so we won't have valid page access to unplugged memory > regions from /proc/kcore. > > Signed-off-by: David Hildenbrand the patch looks good to me as such Acked-by: Michael S. Tsirkin Feel free to merge with rest of patcgset - it seems to mostly live in the fs/mm space. IF you respin, maybe add the explanation you sent in response to Mike's comments in the commit log. > --- > drivers/virtio/virtio_mem.c | 2 ++ > mm/util.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c > index 10ec60d81e84..dc2a2e2b2ff8 100644 > --- a/drivers/virtio/virtio_mem.c > +++ b/drivers/virtio/virtio_mem.c > @@ -1065,6 +1065,7 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, > static void virtio_mem_set_fake_offline(unsigned long pfn, > unsigned long nr_pages, bool onlined) > { > + page_offline_begin(); > for (; nr_pages--; pfn++) { > struct page *page = pfn_to_page(pfn); > > @@ -1075,6 +1076,7 @@ static void virtio_mem_set_fake_offline(unsigned long pfn, > ClearPageReserved(page); > } > } > + page_offline_end(); > } > > /* > diff --git a/mm/util.c b/mm/util.c > index 95395d4e4209..d0e357bd65e6 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -1046,8 +1046,10 @@ void page_offline_begin(void) > { > down_write(&page_offline_rwsem); > } > +EXPORT_SYMBOL(page_offline_begin); > > void page_offline_end(void) > { > up_write(&page_offline_rwsem); > } > +EXPORT_SYMBOL(page_offline_end); > -- > 2.30.2