To improve the code readability.
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Suggested-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
---
mm/swapfile.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index d8fddfb000ec..29da44411734 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -297,13 +297,19 @@ static inline void unlock_cluster(struct swap_cluster_info *ci)
spin_unlock(&ci->lock);
}
+/*
+ * Determine the locking method in use for this device. Return
+ * swap_cluster_info if SSD-style cluster-based locking is in place.
+ */
static inline struct swap_cluster_info *lock_cluster_or_swap_info(
struct swap_info_struct *si,
unsigned long offset)
{
struct swap_cluster_info *ci;
+ /* Try to use fine-grained SSD-style locking if available: */
ci = lock_cluster(si, offset);
+ /* Otherwise, fall back to traditional, coarse locking: */
if (!ci)
spin_lock(&si->lock);
--
2.16.4
