Re: [PATCH v1 6/7] virtio-mem: use page_offline_(start|end) when setting PageOffline()
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-05-03 08:23:57
Also in:
linux-fsdevel, linux-mm, lkml, virtualization
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 <redacted>
the patch looks good to me as such Acked-by: Michael S. Tsirkin <mst@redhat.com> 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.
quoted hunk ↗ jump to hunk
--- 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