[PATCH 3/4] zsmalloc use zs_handle instead of void *
From: Minchan Kim
Date: Thu May 03 2012 - 02:41:13 EST
We should use zs_handle instead of void * to avoid any
confusion. Without this, users may just treat zs_malloc return value as
a pointer and try to deference it.
Cc: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
drivers/staging/zcache/zcache-main.c | 8 ++++----
drivers/staging/zram/zram_drv.c | 8 ++++----
drivers/staging/zram/zram_drv.h | 2 +-
drivers/staging/zsmalloc/zsmalloc-main.c | 28 ++++++++++++++--------------
drivers/staging/zsmalloc/zsmalloc.h | 15 +++++++++++----
5 files changed, 34 insertions(+), 27 deletions(-)
diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
index 2734dac..9b06948 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -700,12 +700,12 @@ static struct zv_hdr *zv_create(struct zs_pool *pool, uint32_t pool_id,
struct zv_hdr *zv;
u32 size = clen + sizeof(struct zv_hdr);
int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
- void *handle = NULL;
+ zs_handle handle;
BUG_ON(!irqs_disabled());
BUG_ON(chunks >= NCHUNKS);
handle = zs_malloc(pool, size);
- if (!handle)
+ if (zs_handle_invalid(handle))
goto out;
atomic_inc(&zv_curr_dist_counts[chunks]);
atomic_inc(&zv_cumul_dist_counts[chunks]);
@@ -721,7 +721,7 @@ out:
return handle;
}
-static void zv_free(struct zs_pool *pool, void *handle)
+static void zv_free(struct zs_pool *pool, zs_handle handle)
{
unsigned long flags;
struct zv_hdr *zv;
@@ -743,7 +743,7 @@ static void zv_free(struct zs_pool *pool, void *handle)
local_irq_restore(flags);
}
-static void zv_decompress(struct page *page, void *handle)
+static void zv_decompress(struct page *page, zs_handle handle)
{
unsigned int clen = PAGE_SIZE;
char *to_va;
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 685d612..7e42aa2 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -135,7 +135,7 @@ static void zram_set_disksize(struct zram *zram, size_t totalram_bytes)
static void zram_free_page(struct zram *zram, size_t index)
{
- void *handle = zram->table[index].handle;
+ zs_handle handle = zram->table[index].handle;
if (unlikely(!handle)) {
/*
@@ -317,7 +317,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
int ret;
u32 store_offset;
size_t clen;
- void *handle;
+ zs_handle handle;
struct zobj_header *zheader;
struct page *page, *page_store;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
@@ -406,7 +406,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
}
handle = zs_malloc(zram->mem_pool, clen + sizeof(*zheader));
- if (!handle) {
+ if (zs_handle_invalid(handle)) {
pr_info("Error allocating memory for compressed "
"page: %u, size=%zu\n", index, clen);
ret = -ENOMEM;
@@ -592,7 +592,7 @@ void __zram_reset_device(struct zram *zram)
/* Free all pages that are still in this zram device */
for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
- void *handle = zram->table[index].handle;
+ zs_handle handle = zram->table[index].handle;
if (!handle)
continue;
diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index fbe8ac9..07d3192 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -81,7 +81,7 @@ enum zram_pageflags {
/* Allocated for each disk page */
struct table {
- void *handle;
+ zs_handle handle;
u16 size; /* object size (excluding header) */
u8 count; /* object ref count (not yet used) */
u8 flags;
diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
index 4496737..51074fa 100644
--- a/drivers/staging/zsmalloc/zsmalloc-main.c
+++ b/drivers/staging/zsmalloc/zsmalloc-main.c
@@ -247,7 +247,7 @@ static void *obj_location_to_handle(struct page *page, unsigned long obj_idx)
}
/* Decode <page, obj_idx> pair from the given object handle */
-static void obj_handle_to_location(void *handle, struct page **page,
+static void obj_handle_to_location(zs_handle handle, struct page **page,
unsigned long *obj_idx)
{
unsigned long hval = (unsigned long)handle;
@@ -571,9 +571,9 @@ EXPORT_SYMBOL_GPL(zs_destroy_pool);
* otherwise NULL.
* Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
*/
-void *zs_malloc(struct zs_pool *pool, size_t size)
+zs_handle zs_malloc(struct zs_pool *pool, size_t size)
{
- void *obj;
+ zs_handle handle;
struct link_free *link;
int class_idx;
struct size_class *class;
@@ -602,8 +602,8 @@ void *zs_malloc(struct zs_pool *pool, size_t size)
class->pages_allocated += class->pages_per_zspage;
}
- obj = first_page->freelist;
- obj_handle_to_location(obj, &m_page, &m_objidx);
+ handle = first_page->freelist;
+ obj_handle_to_location(handle, &m_page, &m_objidx);
m_offset = obj_idx_to_offset(m_page, m_objidx, class->size);
link = (struct link_free *)kmap_atomic(m_page) +
@@ -617,11 +617,11 @@ void *zs_malloc(struct zs_pool *pool, size_t size)
fix_fullness_group(pool, first_page);
spin_unlock(&class->lock);
- return obj;
+ return handle;
}
EXPORT_SYMBOL_GPL(zs_malloc);
-void zs_free(struct zs_pool *pool, void *obj)
+void zs_free(struct zs_pool *pool, zs_handle handle)
{
struct link_free *link;
struct page *first_page, *f_page;
@@ -631,10 +631,10 @@ void zs_free(struct zs_pool *pool, void *obj)
struct size_class *class;
enum fullness_group fullness;
- if (unlikely(!obj))
+ if (unlikely(zs_handle_invalid(handle)))
return;
- obj_handle_to_location(obj, &f_page, &f_objidx);
+ obj_handle_to_location(handle, &f_page, &f_objidx);
first_page = get_first_page(f_page);
get_zspage_mapping(first_page, &class_idx, &fullness);
@@ -648,7 +648,7 @@ void zs_free(struct zs_pool *pool, void *obj)
+ f_offset);
link->next = first_page->freelist;
kunmap_atomic(link);
- first_page->freelist = obj;
+ first_page->freelist = handle;
first_page->inuse--;
fullness = fix_fullness_group(pool, first_page);
@@ -672,7 +672,7 @@ EXPORT_SYMBOL_GPL(zs_free);
* this function. When done with the object, it must be unmapped using
* zs_unmap_object
*/
-void *zs_map_object(struct zs_pool *pool, void *handle)
+void *zs_map_object(struct zs_pool *pool, zs_handle handle)
{
struct page *page;
unsigned long obj_idx, off;
@@ -682,7 +682,7 @@ void *zs_map_object(struct zs_pool *pool, void *handle)
struct size_class *class;
struct mapping_area *area;
- BUG_ON(!handle);
+ BUG_ON(zs_handle_invalid(handle));
obj_handle_to_location(handle, &page, &obj_idx);
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
@@ -712,7 +712,7 @@ void *zs_map_object(struct zs_pool *pool, void *handle)
}
EXPORT_SYMBOL_GPL(zs_map_object);
-void zs_unmap_object(struct zs_pool *pool, void *handle)
+void zs_unmap_object(struct zs_pool *pool, zs_handle handle)
{
struct page *page;
unsigned long obj_idx, off;
@@ -722,7 +722,7 @@ void zs_unmap_object(struct zs_pool *pool, void *handle)
struct size_class *class;
struct mapping_area *area;
- BUG_ON(!handle);
+ BUG_ON(zs_handle_invalid(handle));
obj_handle_to_location(handle, &page, &obj_idx);
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
diff --git a/drivers/staging/zsmalloc/zsmalloc.h b/drivers/staging/zsmalloc/zsmalloc.h
index 949384e..1ba6d0c 100644
--- a/drivers/staging/zsmalloc/zsmalloc.h
+++ b/drivers/staging/zsmalloc/zsmalloc.h
@@ -16,15 +16,22 @@
#include <linux/types.h>
struct zs_pool;
+typedef void * zs_handle;
+
+/*
+ * zs_malloc's caller should use zs_handle_invalid instead of if (!handle)
+ * to test successful allocation.
+ */
+#define zs_handle_invalid(zs_handle) !zs_handle
struct zs_pool *zs_create_pool(const char *name, gfp_t flags);
void zs_destroy_pool(struct zs_pool *pool);
-void *zs_malloc(struct zs_pool *pool, size_t size);
-void zs_free(struct zs_pool *pool, void *obj);
+zs_handle zs_malloc(struct zs_pool *pool, size_t size);
+void zs_free(struct zs_pool *pool, zs_handle handle);
-void *zs_map_object(struct zs_pool *pool, void *handle);
-void zs_unmap_object(struct zs_pool *pool, void *handle);
+void *zs_map_object(struct zs_pool *pool, zs_handle handle);
+void zs_unmap_object(struct zs_pool *pool, zs_handle handle);
u64 zs_get_total_size_bytes(struct zs_pool *pool);
--
1.7.9.5
--
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