From: Huang Ying <ying.huang@xxxxxxxxx> To improve the code readability. Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Suggested-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> 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: Daniel Jordan <daniel.m.jordan@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..e31aa601d9c0 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -297,6 +297,12 @@ static inline void unlock_cluster(struct swap_cluster_info *ci) spin_unlock(&ci->lock); } +/* + * At most times, fine grained cluster lock is sufficient to protect + * the operations on sis->swap_map. No need to acquire gross grained + * sis->lock. But cluster and cluster lock isn't available for HDD, + * so sis->lock will be instead for them. + */ static inline struct swap_cluster_info *lock_cluster_or_swap_info( struct swap_info_struct *si, unsigned long offset) -- 2.16.4
