Hi,
在 2023/08/22 8:13, Song Liu 写道:
On Thu, Aug 3, 2023 at 6:30 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
From: Yu Kuai <yukuai3@xxxxxxxxxx>
Now that active io is initialized when mddev is allocated, it's safe to
call mddev_suspend() before 'mddev->pers' is set.
This also prevent null-ptr-def in some cases that caller doesn't
guarantee 'mddev->pers' to be set.
This description is a little confusing (to me at least). Please revise it.
Sorry about this, how about this:
'active_io' used to be initialized while the array is running, and
'mddev->pers' is set while the array is running as well. Hence caller
must hold 'reconfig_mutex' and guarantee 'mddev->pers' is set before
calling mddev_suspend().
Now that 'active_io' is initialized when mddev is allocated, such
restriction doesn't exist anymore. In the meantime, follow up patches
will refactor mddev_suspend(), hence add checking for 'mddev->pers' to
prevent null-ptr-deref.
Thanks,
Kuai
Other than that, the set looks good to me.
Thanks,
Song
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 897e94a9e47d..f14f2f0a9484 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -448,7 +448,7 @@ void mddev_suspend(struct mddev *mddev)
set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags);
percpu_ref_kill(&mddev->active_io);
- if (mddev->pers->prepare_suspend)
+ if (mddev->pers && mddev->pers->prepare_suspend)
mddev->pers->prepare_suspend(mddev);
wait_event(mddev->sb_wait, percpu_ref_is_zero(&mddev->active_io));
--
2.39.2
.
