Re: [PATCH] mm/migrate_device: Cleanup up PMD Checks and warnings

[SeongJae Park]

On Tue, 14 Apr 2026 19:43:38 +0530 Sunny Patel <nueralspacetech@xxxxxxxxx> wrote:

> Remove the odd VM_WARN_ON_FOLIO(!folio, folio) usage and replace it
> with a simpler VM_WARN_ON_ONCE(!folio) check.
> 
> Drop the redundant VM_WARN_ON_ONCE(!pmd_none(*pmdp) &&
> !is_huge_zero_pmd(*pmdp)).
> 
> Refactor the PMD checks to use pmd_present(), making the control flow
> clearer and avoiding duplicate condition checks.
> 
> Signed-off-by: Sunny Patel <nueralspacetech@xxxxxxxxx>

Acked-by: SeongJae Park <sj@xxxxxxxxxx>

[...]
> @@ -865,12 +864,13 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate,
>  	if (userfaultfd_missing(vma))
>  		goto unlock_abort;
>  
> -	if (!pmd_none(*pmdp)) {
> +	if (pmd_present(*pmdp)) {
>  		if (!is_huge_zero_pmd(*pmdp))
>  			goto unlock_abort;
>  		flush = true;
> -	} else if (!pmd_none(*pmdp))
> +	} else if (!pmd_none(*pmdp)) {
>  		goto unlock_abort;
> +	}

I like this coding style [1] fix.

[1] https://docs.kernel.org/process/coding-style.html#placing-braces-and-spaces


Thanks,
SJ

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