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authorHenry Burns <henryburns@google.com>2019-07-17 01:26:21 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-17 04:23:21 +0200
commitc92d2f38563db20c20c8db2f98fa1349290477d5 (patch)
treed4671d744b5ec48bd7c9ad15ac780f537687aac0 /mm/z3fold.c
parentmm/z3fold.c: remove z3fold_migration trylock (diff)
downloadlinux-c92d2f38563db20c20c8db2f98fa1349290477d5.tar.xz
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mm/z3fold.c: reinitialize zhdr structs after migration
z3fold_page_migration() calls memcpy(new_zhdr, zhdr, PAGE_SIZE). However, zhdr contains fields that can't be directly coppied over (ex: list_head, a circular linked list). We only need to initialize the linked lists in new_zhdr, as z3fold_isolate_page() already ensures that these lists are empty Additionally it is possible that zhdr->work has been placed in a workqueue. In this case we shouldn't migrate the page, as zhdr->work references zhdr as opposed to new_zhdr. Link: http://lkml.kernel.org/r/20190716000520.230595-1-henryburns@google.com Fixes: 1f862989b04ade61d3 ("mm/z3fold.c: support page migration") Signed-off-by: Henry Burns <henryburns@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Vitaly Vul <vitaly.vul@sony.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Jonathan Adams <jwadams@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/z3fold.c')
-rw-r--r--mm/z3fold.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/z3fold.c b/mm/z3fold.c
index 70008a8fed95..6c72b18d8b9c 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -1357,12 +1357,22 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa
z3fold_page_unlock(zhdr);
return -EBUSY;
}
+ if (work_pending(&zhdr->work)) {
+ z3fold_page_unlock(zhdr);
+ return -EAGAIN;
+ }
new_zhdr = page_address(newpage);
memcpy(new_zhdr, zhdr, PAGE_SIZE);
newpage->private = page->private;
page->private = 0;
z3fold_page_unlock(zhdr);
spin_lock_init(&new_zhdr->page_lock);
+ INIT_WORK(&new_zhdr->work, compact_page_work);
+ /*
+ * z3fold_page_isolate() ensures that new_zhdr->buddy is empty,
+ * so we only have to reinitialize it.
+ */
+ INIT_LIST_HEAD(&new_zhdr->buddy);
new_mapping = page_mapping(page);
__ClearPageMovable(page);
ClearPagePrivate(page);