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.
Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Henry Burns <[email protected]> Suggested-by: Vitaly Wool <[email protected]> Acked-by: Vitaly Wool <[email protected]> Acked-by: David Rientjes <[email protected]> Cc: Shakeel Butt <[email protected]> Cc: Vitaly Vul <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Xidong Wang <[email protected]> Cc: Jonathan Adams <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- Changelog since v2: - Removed the WARN_ON entirely, as it is an expected code path. Changelog since v1: - Added an if statement around WARN_ON(trylock_page(page)) to avoid unlocking a page locked by a someone else. mm/z3fold.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index e174d1549734..eeb3fe7f5ca3 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -918,7 +918,16 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, 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: @@ -1325,6 +1334,7 @@ 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); -- 2.22.0.410.gd8fdbe21b5-goog
