mm/swapfile.c: add __swap_entry_free_locked()

The part of __swap_entry_free() with lock held is separated into a new
function __swap_entry_free_locked().  Because we want to reuse that
piece of code in some other places.

Just mechanical code refactoring, there is no any functional change in
this function.

Link: http://lkml.kernel.org/r/20180720071845.17920-8-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 6 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index b30dd0642ccf..d44b2d60a66a 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1123,16 +1123,13 @@ static struct swap_info_struct *swap_info_get_cont(swp_entry_t entry,
         return p;
 }
 
-static unsigned char __swap_entry_free(struct swap_info_struct *p,
-                                       swp_entry_t entry, unsigned char usage)
+static unsigned char __swap_entry_free_locked(struct swap_info_struct *p,
+                                              unsigned long offset,
+                                              unsigned char usage)
 {
-        struct swap_cluster_info *ci;
-        unsigned long offset = swp_offset(entry);
         unsigned char count;
         unsigned char has_cache;
 
-        ci = lock_cluster_or_swap_info(p, offset);
-
         count = p->swap_map[offset];
 
         has_cache = count & SWAP_HAS_CACHE;
@@ -1160,6 +1157,17 @@ static unsigned char __swap_entry_free(struct swap_info_struct *p,
         usage = count | has_cache;
         p->swap_map[offset] = usage ? : SWAP_HAS_CACHE;
 
+        return usage;
+}
+
+static unsigned char __swap_entry_free(struct swap_info_struct *p,
+                                       swp_entry_t entry, unsigned char usage)
+{
+        struct swap_cluster_info *ci;
+        unsigned long offset = swp_offset(entry);
+
+        ci = lock_cluster_or_swap_info(p, offset);
+        usage = __swap_entry_free_locked(p, offset, usage);
         unlock_cluster_or_swap_info(p, ci);
 
         return usage;