On Mon, Aug 21, 2023 at 7:08 PM Yu Kuai [off-list ref] wrote:

Hi,

在 2023/08/22 8:13, Song Liu 写道:

quoted

On Thu, Aug 3, 2023 at 6:30 AM Yu Kuai [off-list ref] wrote:

quoted

From: Yu Kuai <redacted>

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.

This is much better. Thanks!

Song