mm: zswap: further cleanup zswap_store()

- Remove dupentry, reusing entry works just fine.
- Rename pool to shrink_pool, as this one actually is confusing.
- Remove page, use folio_nid() and kmap_local_folio() directly.
- Set entry->swpentry in a common path.
- Move value and src to local scope of use.

Link: https://lkml.kernel.org/r/20240130014208.565554-9-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/zswap.c b/mm/zswap.c
index 82f788a93a33edafa96edca01cbf218921c461dd..1a86659e1173deb2c17e1b33c63bed04e7fd901b 100644 (file)
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1541,14 +1541,11 @@ bool zswap_store(struct folio *folio)
 {
        swp_entry_t swp = folio->swap;
        pgoff_t offset = swp_offset(swp);
-       struct page *page = &folio->page;
        struct zswap_tree *tree = swap_zswap_tree(swp);
        struct zswap_entry *entry, *dupentry;
        struct obj_cgroup *objcg = NULL;
        struct mem_cgroup *memcg = NULL;
-       struct zswap_pool *pool;
-       unsigned long value;
-       u8 *src;
+       struct zswap_pool *shrink_pool;
 
        VM_WARN_ON_ONCE(!folio_test_locked(folio));
        VM_WARN_ON_ONCE(!folio_test_swapcache(folio));
@@ -1563,10 +1560,10 @@ bool zswap_store(struct folio *folio)
         * the tree, and it might be written back overriding the new data.
         */
        spin_lock(&tree->lock);
-       dupentry = zswap_rb_search(&tree->rbroot, offset);
-       if (dupentry) {
+       entry = zswap_rb_search(&tree->rbroot, offset);
+       if (entry) {
+               zswap_invalidate_entry(tree, entry);
                zswap_duplicate_entry++;
-               zswap_invalidate_entry(tree, dupentry);
        }
        spin_unlock(&tree->lock);
 
@@ -1598,17 +1595,19 @@ bool zswap_store(struct folio *folio)
        }
 
        /* allocate entry */
-       entry = zswap_entry_cache_alloc(GFP_KERNEL, page_to_nid(page));
+       entry = zswap_entry_cache_alloc(GFP_KERNEL, folio_nid(folio));
        if (!entry) {
                zswap_reject_kmemcache_fail++;
                goto reject;
        }
 
        if (zswap_same_filled_pages_enabled) {
-               src = kmap_local_page(page);
+               unsigned long value;
+               u8 *src;
+
+               src = kmap_local_folio(folio, 0);
                if (zswap_is_page_same_filled(src, &value)) {
                        kunmap_local(src);
-                       entry->swpentry = swp;
                        entry->length = 0;
                        entry->value = value;
                        atomic_inc(&zswap_same_filled_pages);
@@ -1637,9 +1636,8 @@ bool zswap_store(struct folio *folio)
        if (!zswap_compress(folio, entry))
                goto put_pool;
 
-       entry->swpentry = swp;
-
 insert_entry:
+       entry->swpentry = swp;
        entry->objcg = objcg;
        if (objcg) {
                obj_cgroup_charge_zswap(objcg, entry->length);
@@ -1684,9 +1682,9 @@ reject:
        return false;
 
 shrink:
-       pool = zswap_pool_last_get();
-       if (pool && !queue_work(shrink_wq, &pool->shrink_work))
-               zswap_pool_put(pool);
+       shrink_pool = zswap_pool_last_get();
+       if (shrink_pool && !queue_work(shrink_wq, &shrink_pool->shrink_work))
+               zswap_pool_put(shrink_pool);
        goto reject;
 }