mm: frontswap: split out __frontswap_curr_pages

Code was duplicated in two functions, clean it up.

Also, assert that the deduplicated code runs under the swap spinlock.

Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 17 insertions, 11 deletions

diff --git a/mm/frontswap.c b/mm/frontswap.c
index 7ec53d53c13a..5faf840f8726 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -216,6 +216,20 @@ void __frontswap_invalidate_area(unsigned type)
 }
 EXPORT_SYMBOL(__frontswap_invalidate_area);
 
+static unsigned long __frontswap_curr_pages(void)
+{
+        int type;
+        unsigned long totalpages = 0;
+        struct swap_info_struct *si = NULL;
+
+        assert_spin_locked(&swap_lock);
+        for (type = swap_list.head; type >= 0; type = si->next) {
+                si = swap_info[type];
+                totalpages += atomic_read(&si->frontswap_pages);
+        }
+        return totalpages;
+}
+
 /*
  * Frontswap, like a true swap device, may unnecessarily retain pages
  * under certain circumstances; "shrink" frontswap is essentially a
@@ -240,11 +254,7 @@ void frontswap_shrink(unsigned long target_pages)
          */
         spin_lock(&swap_lock);
         locked = true;
-        total_pages = 0;
-        for (type = swap_list.head; type >= 0; type = si->next) {
-                si = swap_info[type];
-                total_pages += atomic_read(&si->frontswap_pages);
-        }
+        total_pages = __frontswap_curr_pages();
         if (total_pages <= target_pages)
                 goto out;
         total_pages_to_unuse = total_pages - target_pages;
@@ -282,16 +292,12 @@ EXPORT_SYMBOL(frontswap_shrink);
  */
 unsigned long frontswap_curr_pages(void)
 {
-        int type;
         unsigned long totalpages = 0;
-        struct swap_info_struct *si = NULL;
 
         spin_lock(&swap_lock);
-        for (type = swap_list.head; type >= 0; type = si->next) {
-                si = swap_info[type];
-                totalpages += atomic_read(&si->frontswap_pages);
-        }
+        totalpages = __frontswap_curr_pages();
         spin_unlock(&swap_lock);
+
         return totalpages;
 }
 EXPORT_SYMBOL(frontswap_curr_pages);