z3fold: make pages_nr atomic

Convert pages_nr per-pool counter to atomic64_t.

Link: http://lkml.kernel.org/r/20170131213946.b828676ab17bbea42022c213@gmail.com
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Reviewed-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 11 deletions

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 207e5ddc87a2..227378991ecf 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -80,7 +80,7 @@ struct z3fold_pool {
         struct list_head unbuddied[NCHUNKS];
         struct list_head buddied;
         struct list_head lru;
-        u64 pages_nr;
+        atomic64_t pages_nr;
         const struct z3fold_ops *ops;
         struct zpool *zpool;
         const struct zpool_ops *zpool_ops;
@@ -238,7 +238,7 @@ static struct z3fold_pool *z3fold_create_pool(gfp_t gfp,
                 INIT_LIST_HEAD(&pool->unbuddied[i]);
         INIT_LIST_HEAD(&pool->buddied);
         INIT_LIST_HEAD(&pool->lru);
-        pool->pages_nr = 0;
+        atomic64_set(&pool->pages_nr, 0);
         pool->ops = ops;
         return pool;
 }
@@ -350,7 +350,7 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
         if (!page)
                 return -ENOMEM;
         spin_lock(&pool->lock);
-        pool->pages_nr++;
+        atomic64_inc(&pool->pages_nr);
         zhdr = init_z3fold_page(page);
 
         if (bud == HEADLESS) {
@@ -443,10 +443,9 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
                 return;
         }
 
-        if (bud != HEADLESS) {
-                /* Remove from existing buddy list */
+        /* Remove from existing buddy list */
+        if (bud != HEADLESS)
                 list_del(&zhdr->buddy);
-        }
 
         if (bud == HEADLESS ||
             (zhdr->first_chunks == 0 && zhdr->middle_chunks == 0 &&
@@ -455,7 +454,7 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
                 list_del(&page->lru);
                 clear_bit(PAGE_HEADLESS, &page->private);
                 free_z3fold_page(zhdr);
-                pool->pages_nr--;
+                atomic64_dec(&pool->pages_nr);
         } else {
                 z3fold_compact_page(zhdr);
                 /* Add to the unbuddied list */
@@ -573,7 +572,7 @@ next:
                          */
                         clear_bit(PAGE_HEADLESS, &page->private);
                         free_z3fold_page(zhdr);
-                        pool->pages_nr--;
+                        atomic64_dec(&pool->pages_nr);
                         spin_unlock(&pool->lock);
                         return 0;
                 }  else if (!test_bit(PAGE_HEADLESS, &page->private)) {
@@ -676,12 +675,11 @@ static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle)
  * z3fold_get_pool_size() - gets the z3fold pool size in pages
  * @pool:       pool whose size is being queried
  *
- * Returns: size in pages of the given pool.  The pool lock need not be
- * taken to access pages_nr.
+ * Returns: size in pages of the given pool.
  */
 static u64 z3fold_get_pool_size(struct z3fold_pool *pool)
 {
-        return pool->pages_nr;
+        return atomic64_read(&pool->pages_nr);
 }
 
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