mm/z3fold.c: lock z3fold page before __SetPageMovable()

Following zsmalloc.c's example we call trylock_page() and unlock_page().
Also make z3fold_page_migrate() assert that newpage is passed in locked,
as per the documentation.

[akpm@linux-foundation.org: fix trylock_page return value test, per Shakeel]
Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@google.com
Link: http://lkml.kernel.org/r/20190702233538.52793-1-henryburns@google.com
Signed-off-by: Henry Burns <henryburns@google.com>
Suggested-by: Vitaly Wool <vitalywool@gmail.com>
Acked-by: Vitaly Wool <vitalywool@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Vitaly Vul <vitaly.vul@sony.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Xidong Wang <wangxidong_97@163.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Henry Burns 2019-07-11 20:52:14 -07:00 committed by Linus Torvalds
parent dd9239900e
commit 810481a246

View file

@ -924,7 +924,16 @@ retry:
set_bit(PAGE_HEADLESS, &page->private);
goto headless;
}
__SetPageMovable(page, pool->inode->i_mapping);
if (can_sleep) {
lock_page(page);
__SetPageMovable(page, pool->inode->i_mapping);
unlock_page(page);
} else {
if (trylock_page(page)) {
__SetPageMovable(page, pool->inode->i_mapping);
unlock_page(page);
}
}
z3fold_page_lock(zhdr);
found:
@ -1331,6 +1340,7 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa
VM_BUG_ON_PAGE(!PageMovable(page), page);
VM_BUG_ON_PAGE(!PageIsolated(page), page);
VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
zhdr = page_address(page);
pool = zhdr_to_pool(zhdr);