2022-10-10 03:49:21

by XU pengfei

Subject: [PATCH V2] mm/mmap_lock: Remove unnecessary 'NULL' values from Pointer

Pointer variables allocate memory first, and then judge. There is no
need to initialize the assignment.

Signed-off-by: XU pengfei <[email protected]>
Reported-by: kernel test robot <[email protected]>
---
V2: Remove goto statement

mm/mmap_lock.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c
index 1854850b4b89..d0c2a5eae341 100644
--- a/mm/mmap_lock.c
+++ b/mm/mmap_lock.c
@@ -198,23 +198,24 @@ void trace_mmap_lock_unreg(void)
*/
static const char *get_mm_memcg_path(struct mm_struct *mm)
{
- char *buf = NULL;
+ char *buf;
struct mem_cgroup *memcg = get_mem_cgroup_from_mm(mm);

if (memcg == NULL)
- goto out;
- if (unlikely(memcg->css.cgroup == NULL))
- goto out_put;
+ return NULL;
+ if (unlikely(memcg->css.cgroup == NULL)) {
+ css_put(&memcg->css);
+ return NULL;
+ }

buf = get_memcg_path_buf();
- if (buf == NULL)
- goto out_put;
+ if (buf == NULL) {
+ css_put(&memcg->css);
+ return NULL;
+ }

cgroup_path(memcg->css.cgroup, buf, MEMCG_PATH_BUF_SIZE);

-out_put:
- css_put(&memcg->css);
-out:
return buf;
}

--
2.18.2

2022-10-10 03:59:35

by Matthew Wilcox

Subject: Re: [PATCH V2] mm/mmap_lock: Remove unnecessary 'NULL' values from Pointer

On Mon, Oct 10, 2022 at 11:42:38AM +0800, XU pengfei wrote:
> Pointer variables allocate memory first, and then judge. There is no
> need to initialize the assignment.

This seems worse to me.