Re: [PATCH v5 2/3] mm/swap: use swap_ops to register swap device's methods

[Kairui Song]

On Mon, May 11, 2026 at 8:17 PM Baoquan He <baoquan.he@xxxxxxxxx> wrote:
> Speaking of comments, do you think below sentences are OK to you?
>
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index 82d2c9b35b11..8012e5e334f9 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -3518,10 +3518,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
>                 goto bad_swap_unlock_inode;
>         }
>
> -       error = init_swap_ops(si);
> -       if (error)
> -               goto bad_swap_unlock_inode;
> -
>         si->max = maxpages;
>         si->pages = maxpages - 1;
>         nr_extents = setup_swap_extents(si, swap_file, &span);
> @@ -3616,6 +3612,15 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
>                 goto free_swap_zswap;
>         }
>
> +       /*
> +        * init_swap_ops() sets si->ops based on flags. It does not need
> +        * swapon_mutex, and must complete before enable_swap_info()
> +        * exposes the device.
> +        */
> +       error = init_swap_ops(si);
> +       if (error)
> +               goto bad_swap_unlock_inode;
> +

Right, LGTM!
>         mutex_lock(&swapon_mutex);
>         prio = DEF_SWAP_PRIO;
>         if (swap_flags & SWAP_FLAG_PREFER)