mm/z3fold: move decrement of pool->pages_nr into __release_z3fold_page()

The z3fold will always do atomic64_dec(&pool->pages_nr) when the
__release_z3fold_page() is called.  Thus we can move decrement of
pool->pages_nr into __release_z3fold_page() to simplify the code.

Also we can reduce the size of z3fold.o ~1k.

Without this patch:
   text	   data	    bss	    dec	    hex	filename
  15444	   1376	      8	  16828	   41bc	mm/z3fold.o
With this patch:
   text	   data	    bss	    dec	    hex	filename
  15044	   1248	      8	  16300	   3fac	mm/z3fold.o

Link: https://lkml.kernel.org/r/20220308134311.59086-7-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/z3fold.c b/mm/z3fold.c
index adc0b3fa4906ca217aa22d5abd599de13d6ac61c..18a697f6fe3216459df827fe09c6182e673d03b9 100644 (file)
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -520,6 +520,8 @@ static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked)
        list_add(&zhdr->buddy, &pool->stale);
        queue_work(pool->release_wq, &pool->work);
        spin_unlock(&pool->stale_lock);
+
+       atomic64_dec(&pool->pages_nr);
 }
 
 static void release_z3fold_page(struct kref *ref)
@@ -737,13 +739,9 @@ static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr)
        return new_zhdr;
 
 out_fail:
-       if (new_zhdr) {
-               if (kref_put(&new_zhdr->refcount, release_z3fold_page_locked))
-                       atomic64_dec(&pool->pages_nr);
-               else {
-                       add_to_unbuddied(pool, new_zhdr);
-                       z3fold_page_unlock(new_zhdr);
-               }
+       if (new_zhdr && !kref_put(&new_zhdr->refcount, release_z3fold_page_locked)) {
+               add_to_unbuddied(pool, new_zhdr);
+               z3fold_page_unlock(new_zhdr);
        }
        return NULL;
 
@@ -816,10 +814,8 @@ static void do_compact_page(struct z3fold_header *zhdr, bool locked)
        list_del_init(&zhdr->buddy);
        spin_unlock(&pool->lock);
 
-       if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
-               atomic64_dec(&pool->pages_nr);
+       if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
                return;
-       }
 
        if (test_bit(PAGE_STALE, &page->private) ||
            test_and_set_bit(PAGE_CLAIMED, &page->private)) {
@@ -829,9 +825,7 @@ static void do_compact_page(struct z3fold_header *zhdr, bool locked)
 
        if (!zhdr->foreign_handles && buddy_single(zhdr) &&
            zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) {
-               if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
-                       atomic64_dec(&pool->pages_nr);
-               else {
+               if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
                        clear_bit(PAGE_CLAIMED, &page->private);
                        z3fold_page_unlock(zhdr);
                }
@@ -1089,10 +1083,8 @@ retry:
                if (zhdr) {
                        bud = get_free_buddy(zhdr, chunks);
                        if (bud == HEADLESS) {
-                               if (kref_put(&zhdr->refcount,
+                               if (!kref_put(&zhdr->refcount,
                                             release_z3fold_page_locked))
-                                       atomic64_dec(&pool->pages_nr);
-                               else
                                        z3fold_page_unlock(zhdr);
                                pr_err("No free chunks in unbuddied\n");
                                WARN_ON(1);
@@ -1239,10 +1231,8 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
 
        if (!page_claimed)
                free_handle(handle, zhdr);
-       if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) {
-               atomic64_dec(&pool->pages_nr);
+       if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list))
                return;
-       }
        if (page_claimed) {
                /* the page has not been claimed by us */
                put_z3fold_header(zhdr);
@@ -1353,9 +1343,7 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
                                break;
                        }
                        if (!z3fold_page_trylock(zhdr)) {
-                               if (kref_put(&zhdr->refcount,
-                                               release_z3fold_page))
-                                       atomic64_dec(&pool->pages_nr);
+                               kref_put(&zhdr->refcount, release_z3fold_page);
                                zhdr = NULL;
                                continue; /* can't evict at this point */
                        }
@@ -1366,10 +1354,8 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
                         */
                        if (zhdr->foreign_handles ||
                            test_and_set_bit(PAGE_CLAIMED, &page->private)) {
-                               if (kref_put(&zhdr->refcount,
+                               if (!kref_put(&zhdr->refcount,
                                                release_z3fold_page_locked))
-                                       atomic64_dec(&pool->pages_nr);
-                               else
                                        z3fold_page_unlock(zhdr);
                                zhdr = NULL;
                                continue; /* can't evict such page */
@@ -1447,7 +1433,6 @@ next:
                        if (kref_put(&zhdr->refcount,
                                        release_z3fold_page_locked)) {
                                kmem_cache_free(pool->c_handle, slots);
-                               atomic64_dec(&pool->pages_nr);
                                return 0;
                        }
                        /*
@@ -1669,10 +1654,8 @@ static void z3fold_page_putback(struct page *page)
        if (!list_empty(&zhdr->buddy))
                list_del_init(&zhdr->buddy);
        INIT_LIST_HEAD(&page->lru);
-       if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
-               atomic64_dec(&pool->pages_nr);
+       if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
                return;
-       }
        spin_lock(&pool->lock);
        list_add(&page->lru, &pool->lru);
        spin_unlock(&pool->lock);