mm: zswap: make same_filled functions folio-friendly

A variable name 'page' is used in zswap_is_folio_same_filled() and
zswap_fill_page() to point at the kmapped data in a folio. Use 'data'
instead to avoid confusion and stop it from showing up when searching
for 'page' references in mm/zswap.c.

While we are at it, move the kmap/kunmap calls into zswap_fill_page(),
make it take in a folio, and rename it to zswap_fill_folio().

Link: https://lkml.kernel.org/r/20240524033819.1953587-4-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/zswap.c b/mm/zswap.c
index bac66991fb14eba98f69d6a5f874b11ab20cbdb0..b9b35ef86d9be5e3560e93cade504a4a26a72540 100644 (file)
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1375,35 +1375,35 @@ resched:
 **********************************/
 static bool zswap_is_folio_same_filled(struct folio *folio, unsigned long *value)
 {
-       unsigned long *page;
+       unsigned long *data;
        unsigned long val;
-       unsigned int pos, last_pos = PAGE_SIZE / sizeof(*page) - 1;
+       unsigned int pos, last_pos = PAGE_SIZE / sizeof(*data) - 1;
        bool ret = false;
 
-       page = kmap_local_folio(folio, 0);
-       val = page[0];
+       data = kmap_local_folio(folio, 0);
+       val = data[0];
 
-       if (val != page[last_pos])
+       if (val != data[last_pos])
                goto out;
 
        for (pos = 1; pos < last_pos; pos++) {
-               if (val != page[pos])
+               if (val != data[pos])
                        goto out;
        }
 
        *value = val;
        ret = true;
 out:
-       kunmap_local(page);
+       kunmap_local(data);
        return ret;
 }
 
-static void zswap_fill_page(void *ptr, unsigned long value)
+static void zswap_fill_folio(struct folio *folio, unsigned long value)
 {
-       unsigned long *page;
+       unsigned long *data = kmap_local_folio(folio, 0);
 
-       page = (unsigned long *)ptr;
-       memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
+       memset_l(data, value, PAGE_SIZE / sizeof(unsigned long));
+       kunmap_local(data);
 }
 
 /*********************************
@@ -1554,7 +1554,6 @@ bool zswap_load(struct folio *folio)
        bool swapcache = folio_test_swapcache(folio);
        struct xarray *tree = swap_zswap_tree(swp);
        struct zswap_entry *entry;
-       u8 *dst;
 
        VM_WARN_ON_ONCE(!folio_test_locked(folio));
 
@@ -1580,11 +1579,8 @@ bool zswap_load(struct folio *folio)
 
        if (entry->length)
                zswap_decompress(entry, folio);
-       else {
-               dst = kmap_local_folio(folio, 0);
-               zswap_fill_page(dst, entry->value);
-               kunmap_local(dst);
-       }
+       else
+               zswap_fill_folio(folio, entry->value);
 
        count_vm_event(ZSWPIN);
        if (entry->objcg)