[PATCH v2 2/2] mm/swap: Add lockdep for si->global_cluster_lock in swap_cluster_alloc_table()

[Hui Zhu]

From: Hui Zhu <zhuhui@xxxxxxxxxx>

Add a lockdep_assert_held(&si->global_cluster_lock) in
swap_cluster_alloc_table() for non-SWP_SOLIDSTATE devices.

The function already requires the caller to hold both ci->lock
and percpu_swap_cluster.lock.
And it also necessitates si->global_cluster_lock when the device is not
SWP_SOLIDSTATE.

Adding this assertion ensures locking consistency and helps catch
potential synchronization issues during development.
Change the order of lockdep_assert_held() to match the actual lock
acquisition order.

Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx>
---
 mm/swapfile.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 3fc2eb30c187..b31b86263b89 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -476,8 +476,10 @@ swap_cluster_alloc_table(struct swap_info_struct *si,
 	 * Only cluster isolation from the allocator does table allocation.
 	 * Swap allocator uses percpu clusters and holds the local lock.
 	 */
-	lockdep_assert_held(&ci->lock);
 	lockdep_assert_held(&this_cpu_ptr(&percpu_swap_cluster)->lock);
+	if (!(si->flags & SWP_SOLIDSTATE))
+		lockdep_assert_held(&si->global_cluster_lock);
+	lockdep_assert_held(&ci->lock);
 
 	/* The cluster must be free and was just isolated from the free list. */
 	VM_WARN_ON_ONCE(ci->flags || !cluster_is_empty(ci));
-- 
2.43.0