mm/zswap.c: allow handling just same-value filled pages

[sfrench/cifs-2.6.git] / mm / zswap.c

diff --git a/mm/zswap.c b/mm/zswap.c
index cdf6950fcb2e39718864e38fddab7aa22feaa818..3efd8cae315e79382ac213478e55aa6393c9332c 100644 (file)
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -120,11 +120,19 @@ static unsigned int zswap_accept_thr_percent = 90; /* of max pool size */
 module_param_named(accept_threshold_percent, zswap_accept_thr_percent,
                   uint, 0644);
 
-/* Enable/disable handling same-value filled pages (enabled by default) */
+/*
+ * Enable/disable handling same-value filled pages (enabled by default).
+ * If disabled every page is considered non-same-value filled.
+ */
 static bool zswap_same_filled_pages_enabled = true;
 module_param_named(same_filled_pages_enabled, zswap_same_filled_pages_enabled,
                   bool, 0644);
 
+/* Enable/disable handling non-same-value filled pages (enabled by default) */
+static bool zswap_non_same_filled_pages_enabled = true;
+module_param_named(non_same_filled_pages_enabled, zswap_non_same_filled_pages_enabled,
+                  bool, 0644);
+
 /*********************************
 * data structures
 **********************************/
@@ -1147,6 +1155,11 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
                kunmap_atomic(src);
        }
 
+       if (!zswap_non_same_filled_pages_enabled) {
+               ret = -EINVAL;
+               goto freepage;
+       }
+
        /* if entry is successfully added, it keeps the reference */
        entry->pool = zswap_pool_current_get();
        if (!entry->pool) {