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staging: zcache: fix crash on high memory swap

zcache_put_page() was modified to pass page_address(page) instead of the
actual page structure. In combination with the function signature changes
to tmem_put() and zcache_pampd_create(), zcache_pampd_create() tries to
(re)derive the page structure from the virtual address.  However, if the
original page is a high memory page (or any unmapped page), this
virt_to_page() fails because the page_address() in zcache_put_page()
returned NULL.

This patch changes zcache_put_page() and zcache_get_page() to pass
the page structure instead of the page's virtual address, which
may or may not exist.

Signed-off-by: Seth Jennings <>
Acked-by: Dan Magenheimer <>
Signed-off-by: Greg Kroah-Hartman <>
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commit c5f5c4db393837ebb2ae47bf061d70e498f48f8c 1 parent 20cc799
Seth Jennings authored gregkh committed
Showing with 4 additions and 4 deletions.
  1. +4 −4 drivers/staging/zcache/zcache-main.c
8 drivers/staging/zcache/zcache-main.c
@@ -1158,7 +1158,7 @@ static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
size_t clen;
int ret;
unsigned long count;
- struct page *page = virt_to_page(data);
+ struct page *page = (struct page *)(data);
struct zcache_client *cli = pool->client;
uint16_t client_id = get_client_id_from_client(cli);
unsigned long zv_mean_zsize;
@@ -1227,7 +1227,7 @@ static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
int ret = 0;
- zv_decompress(virt_to_page(data), pampd);
+ zv_decompress((struct page *)(data), pampd);
return ret;
@@ -1539,7 +1539,7 @@ static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
goto out;
if (!zcache_freeze && zcache_do_preload(pool) == 0) {
/* preload does preempt_disable on success */
- ret = tmem_put(pool, oidp, index, page_address(page),
+ ret = tmem_put(pool, oidp, index, (char *)(page),
PAGE_SIZE, 0, is_ephemeral(pool));
if (ret < 0) {
if (is_ephemeral(pool))
@@ -1572,7 +1572,7 @@ static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
pool = zcache_get_pool_by_id(cli_id, pool_id);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_get(pool, oidp, index, page_address(page),
+ ret = tmem_get(pool, oidp, index, (char *)(page),
&size, 0, is_ephemeral(pool));
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