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/20190702005122.41036-1-henrybu...@google.com
Signed-off-by: Henry Burns
Suggested-by: Vitaly Wool
Acked-by: Vitaly Wool
Acked-by: David Rientjes
Cc: Shakeel Butt
Cc: Vitaly Vul
Cc: Mike Rapoport
Cc: Xidong Wang
Cc: Jonathan Adams
Cc:
Signed-off-by: Andrew Morton
---
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, >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
