staging: zcache: fix account foregin counters against zero-filled pages

zero-filled pages won't be compressed and sent to remote system. Monitor
the number ephemeral and persistent pages that Ramster has sent make no
sense. This patch skip account foregin counters against zero-filled pages.

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/zcache/zcache-main.c

@@ -415,7 +415,7 @@ static void *zcache_pampd_eph_create(char *data, size_t size, bool raw,
 got_pampd:
 	inc_zcache_eph_zbytes(clen);
 	inc_zcache_eph_zpages();
-	if (ramster_enabled && raw)
+	if (ramster_enabled && raw && !zero_filled)
 		ramster_count_foreign_pages(true, 1);
 	if (zero_filled)
 		pampd = (void *)ZERO_FILLED;
@@ -500,7 +500,7 @@ static void *zcache_pampd_pers_create(char *data, size_t size, bool raw,
 got_pampd:
 	inc_zcache_pers_zpages();
 	inc_zcache_pers_zbytes(clen);
-	if (ramster_enabled && raw)
+	if (ramster_enabled && raw && !zero_filled)
 		ramster_count_foreign_pages(false, 1);
 	if (zero_filled)
 		pampd = (void *)ZERO_FILLED;
@@ -681,7 +681,7 @@ static int zcache_pampd_get_data_and_free(char *data, size_t *sizep, bool raw,
 		dec_zcache_pers_zpages(zpages);
 		dec_zcache_pers_zbytes(zsize);
 	}
-	if (!is_local_client(pool->client))
+	if (!is_local_client(pool->client) && !zero_filled)
 		ramster_count_foreign_pages(eph, -1);
 	if (page && !zero_filled)
 		zcache_free_page(page);
@@ -732,7 +732,7 @@ static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
 		dec_zcache_pers_zpages(zpages);
 		dec_zcache_pers_zbytes(zsize);
 	}
-	if (!is_local_client(pool->client))
+	if (!is_local_client(pool->client) && !zero_filled)
 		ramster_count_foreign_pages(is_ephemeral(pool), -1);
 	if (page && !zero_filled)
 		zcache_free_page(page);