[PATCH] mm: fix z3fold warnings on CONFIG_SMP=n

From: Alex Xu (Hello71)
Date: Thu Sep 27 2018 - 16:27:27 EST


Spinlocks are always lockable on UP systems, even if they were just
locked.

Cc: Dan Streetman <ddstreet@xxxxxxxx>
Signed-off-by: Alex Xu (Hello71) <alex_y_xu@xxxxxxxx>
---
mm/z3fold.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 4b366d181..4e6ad2de4 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -202,6 +202,13 @@ static inline void z3fold_page_lock(struct z3fold_header *zhdr)
spin_lock(&zhdr->page_lock);
}

+static inline void z3fold_page_ensure_locked(struct z3fold_header *zhdr)
+{
+#ifdef CONFIG_SMP
+ WARN_ON(z3fold_page_trylock(zhdr));
+#endif
+}
+
/* Try to lock a z3fold page */
static inline int z3fold_page_trylock(struct z3fold_header *zhdr)
{
@@ -277,7 +284,7 @@ static void release_z3fold_page_locked(struct kref *ref)
{
struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
refcount);
- WARN_ON(z3fold_page_trylock(zhdr));
+ z3fold_page_ensure_locked(zhdr);
__release_z3fold_page(zhdr, true);
}

@@ -289,7 +296,7 @@ static void release_z3fold_page_locked_list(struct kref *ref)
list_del_init(&zhdr->buddy);
spin_unlock(&zhdr->pool->lock);

- WARN_ON(z3fold_page_trylock(zhdr));
+ z3fold_page_ensure_locked(zhdr);
__release_z3fold_page(zhdr, true);
}

@@ -403,7 +410,7 @@ static void do_compact_page(struct z3fold_header *zhdr, bool locked)

page = virt_to_page(zhdr);
if (locked)
- WARN_ON(z3fold_page_trylock(zhdr));
+ z3fold_page_ensure_locked(zhdr);
else
z3fold_page_lock(zhdr);
if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) {
--
2.19.0