From bdcde42d74a12e170971038671a80ef00603ae4e Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Tue, 2 Apr 2013 10:46:13 +0800 Subject: [PATCH] staging: zcache: introduce zero-filled pages handler Introduce zero-filled pages handler to capture and handle zero pages. Acked-by: Dan Magenheimer Signed-off-by: Wanpeng Li Signed-off-by: Greg Kroah-Hartman --- drivers/staging/zcache/zcache-main.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c index fb699df30713..274a48e94cfe 100644 --- a/drivers/staging/zcache/zcache-main.c +++ b/drivers/staging/zcache/zcache-main.c @@ -277,6 +277,33 @@ static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool) kmem_cache_free(zcache_obj_cache, obj); } +static bool page_is_zero_filled(void *ptr) +{ + unsigned int pos; + unsigned long *page; + + page = (unsigned long *)ptr; + + for (pos = 0; pos < PAGE_SIZE / sizeof(*page); pos++) { + if (page[pos]) + return false; + } + + return true; +} + +static void handle_zero_filled_page(void *p) +{ + void *user_mem; + struct page *page = (struct page *)p; + + user_mem = kmap_atomic(page); + memset(user_mem, 0, PAGE_SIZE); + kunmap_atomic(user_mem); + + flush_dcache_page(page); +} + static struct tmem_hostops zcache_hostops = { .obj_alloc = zcache_obj_alloc, .obj_free = zcache_obj_free, -- 2.39.2