* [PATCH] mm: userfaultfd: Use swap() in double_pt_lock()
@ 2024-05-31 9:16 Jiapeng Chong
2024-05-31 10:02 ` David Hildenbrand
0 siblings, 1 reply; 2+ messages in thread
From: Jiapeng Chong @ 2024-05-31 9:16 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, Jiapeng Chong, Abaci Robot
Use existing swap() function rather than duplicating its implementation.
./mm/userfaultfd.c:1006:13-14: WARNING opportunity for swap()
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9266
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
mm/userfaultfd.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index defa5109cc62..5e7f2801698a 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -995,14 +995,8 @@ void double_pt_lock(spinlock_t *ptl1,
__acquires(ptl1)
__acquires(ptl2)
{
- spinlock_t *ptl_tmp;
-
- if (ptl1 > ptl2) {
- /* exchange ptl1 and ptl2 */
- ptl_tmp = ptl1;
- ptl1 = ptl2;
- ptl2 = ptl_tmp;
- }
+ if (ptl1 > ptl2)
+ swap(ptl1, ptl2);
/* lock in virtual address order to avoid lock inversion */
spin_lock(ptl1);
if (ptl1 != ptl2)
--
2.20.1.7.g153144c
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] mm: userfaultfd: Use swap() in double_pt_lock()
2024-05-31 9:16 [PATCH] mm: userfaultfd: Use swap() in double_pt_lock() Jiapeng Chong
@ 2024-05-31 10:02 ` David Hildenbrand
0 siblings, 0 replies; 2+ messages in thread
From: David Hildenbrand @ 2024-05-31 10:02 UTC (permalink / raw)
To: Jiapeng Chong, akpm; +Cc: linux-mm, linux-kernel, Abaci Robot
On 31.05.24 11:16, Jiapeng Chong wrote:
> Use existing swap() function rather than duplicating its implementation.
>
> ./mm/userfaultfd.c:1006:13-14: WARNING opportunity for swap()
>
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9266
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
> mm/userfaultfd.c | 10 ++--------
> 1 file changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
> index defa5109cc62..5e7f2801698a 100644
> --- a/mm/userfaultfd.c
> +++ b/mm/userfaultfd.c
> @@ -995,14 +995,8 @@ void double_pt_lock(spinlock_t *ptl1,
> __acquires(ptl1)
> __acquires(ptl2)
> {
> - spinlock_t *ptl_tmp;
> -
> - if (ptl1 > ptl2) {
> - /* exchange ptl1 and ptl2 */
> - ptl_tmp = ptl1;
> - ptl1 = ptl2;
> - ptl2 = ptl_tmp;
> - }
> + if (ptl1 > ptl2)
> + swap(ptl1, ptl2);
> /* lock in virtual address order to avoid lock inversion */
> spin_lock(ptl1);
> if (ptl1 != ptl2)
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Cheers,
David / dhildenb
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