Re: [PATCH 2/4] mm, swap: Move setup_swap_clusters_info() after SWP_SOLIDSTATE initialization

[Luiz Capitulino]

On 2026-07-20 03:13, Kemeng Shi wrote:
> In setup_swap_clusters_info(), SWP_SOLIDSTATE is used to decide
> global_cluster allocation. Move setup_swap_clusters_info() after
> SWP_SOLIDSTATE initialization to avoid unneeded global_cluster
> allocation.
>
> Fixes: 451c6326105b2 ("mm, swap: clean up swapon process and locking")
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>

I was about to send the same fix :) (one nit below)

> ---
>   mm/swapfile.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index d29062d9c3cd..81c4040912be 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -3607,11 +3607,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
>   
>   	maxpages = si->max;
>   
> -	/* Set up the swap cluster info */
> -	error = setup_swap_clusters_info(si, swap_header, maxpages);
> -	if (error)
> -		goto bad_swap_unlock_inode;
> -
>   	if (si->bdev && bdev_stable_writes(si->bdev))
>   		si->flags |= SWP_STABLE_WRITES;
>   
> @@ -3625,6 +3620,14 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
>   		inced_nr_rotate_swap = true;
>   	}
>   
> +	/*
> +	 * Set up the swap cluster info. SWP_SOLIDSTATE is used for
> +	 * global_cluster allocation
> +	 */

Maybe something like:

/*
 * Set up the swap cluster info after SWP_ flags handling as
 * setup_swap_clusters_info() checks SWP_SOLIDSTATE.
 */

As it's minor:

Reviewed-by: Luiz Capitulino <luizcap@xxxxxxxxxx>

> +	error = setup_swap_clusters_info(si, swap_header, maxpages);
> +	if (error)
> +		goto bad_swap_unlock_inode;
> +
>   	if ((swap_flags & SWAP_FLAG_DISCARD) &&
>   	    si->bdev && bdev_max_discard_sectors(si->bdev)) {
>   		/*