The patch titled
Subject: zsmalloc: zs_malloc: return ERR_PTR on failure
has been added to the -mm mm-unstable branch. Its filename is
zsmalloc-zs_malloc-return-err_ptr-if-fail.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zsmalloc-zs_malloc-return-err_ptr-if-fail.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Hui Zhu <teawater@xxxxxxxxxxxx>
Subject: zsmalloc: zs_malloc: return ERR_PTR on failure
Date: Thu, 14 Jul 2022 16:07:57 +0800
zs_malloc returns 0 if it fails. zs_zpool_malloc will return -1 when
zs_malloc return 0. But -1 makes the return value unclear.
For example, when zswap_frontswap_store calls zs_malloc through
zs_zpool_malloc, it will return -1 to its caller. The other return value
is -EINVAL, -ENODEV or something else.
This commit changes zs_malloc to return ERR_PTR on failure. It didn't
just let zs_zpool_malloc return -ENOMEM becaue zs_malloc has two types of
failure:
- size is not OK return -EINVAL
- memory alloc fail return -ENOMEM.
Link: https://lkml.kernel.org/r/20220714080757.12161-1-teawater@xxxxxxxxx
Signed-off-by: Hui Zhu <teawater@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 4 ++--
mm/zsmalloc.c | 13 ++++++++-----
2 files changed, 10 insertions(+), 7 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zsmalloc-zs_malloc-return-err_ptr-if-fail
+++ a/drivers/block/zram/zram_drv.c
@@ -1389,9 +1389,9 @@ static int __zram_bvec_write(struct zram
__GFP_HIGHMEM |
__GFP_MOVABLE);
- if (unlikely(!handle)) {
+ if (IS_ERR((void *)handle)) {
zcomp_stream_put(zram->comp);
- return -ENOMEM;
+ return PTR_ERR((void *)handle);
}
alloced_pages = zs_get_total_pages(zram->mem_pool);
--- a/mm/zsmalloc.c~zsmalloc-zs_malloc-return-err_ptr-if-fail
+++ a/mm/zsmalloc.c
@@ -399,7 +399,10 @@ static int zs_zpool_malloc(void *pool, s
unsigned long *handle)
{
*handle = zs_malloc(pool, size, gfp);
- return *handle ? 0 : -1;
+
+ if (IS_ERR((void *)(*handle)))
+ return PTR_ERR((void *)*handle);
+ return 0;
}
static void zs_zpool_free(void *pool, unsigned long handle)
{
@@ -1400,7 +1403,7 @@ static unsigned long obj_malloc(struct z
* @gfp: gfp flags when allocating object
*
* On success, handle to the allocated object is returned,
- * otherwise 0.
+ * otherwise an ERR_PTR().
* Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
*/
unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
@@ -1411,11 +1414,11 @@ unsigned long zs_malloc(struct zs_pool *
struct zspage *zspage;
if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
- return 0;
+ return (unsigned long)ERR_PTR(-EINVAL);
handle = cache_alloc_handle(pool, gfp);
if (!handle)
- return 0;
+ return (unsigned long)ERR_PTR(-ENOMEM);
/* extra space in chunk to keep the handle */
size += ZS_HANDLE_SIZE;
@@ -1440,7 +1443,7 @@ unsigned long zs_malloc(struct zs_pool *
zspage = alloc_zspage(pool, class, gfp);
if (!zspage) {
cache_free_handle(pool, handle);
- return 0;
+ return (unsigned long)ERR_PTR(-ENOMEM);
}
spin_lock(&class->lock);
_
Patches currently in -mm which might be from teawater@xxxxxxxxxxxx are
zsmalloc-zs_malloc-return-err_ptr-if-fail.patch
