linux-kernel - Re: [PATCH 1/5] mm/vmalloc: remove the unnecessary type check

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Date:   Mon, 6 Jun 2022 22:36:03 +0200
From:   Uladzislau Rezki <urezki@...il.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     akpm@...ux-foundation.org, npiggin@...il.com, urezki@...il.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] mm/vmalloc: remove the unnecessary type check

> In function adjust_va_to_fit_type(), it checks all values of passed
> in fit type, including NOTHING_FIT in the else branch. In fact, it's
> unnecessary to check NOTHING_FIT since the check has been done before
> adjust_va_to_fit_type() is called in all call sites. So clean it up.
> 
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
>  mm/vmalloc.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 07db42455dd4..b7a138ab7b79 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1418,8 +1418,6 @@ adjust_va_to_fit_type(struct vmap_area *va,
>  		 * Shrink this VA to remaining size.
>  		 */
>  		va->va_start = nva_start_addr + size;
> -	} else {
> -		return -1;
>  	}
>  
>  	if (type != FL_FIT_TYPE) {
> -- 
> 2.34.1
> 
Why not just invoke the classify_va_fit_type() inside the adjust_va_to_fit_type()?
In this case we do not need to rely on upper-stack checks and the split logic 
becomes fully implemented in one solid function.

--
Uladzislau Rezki