linux-kernel - Re: [PATCH v3 1/3] mm: vmalloc: Avoid calling __find_vmap_area() twice in _

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Message-ID: <Y6Vkjr7DNEEv4MW5@infradead.org>
Date:   Fri, 23 Dec 2022 00:19:26 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     "Uladzislau Rezki (Sony)" <urezki@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        LKML <linux-kernel@...r.kernel.org>, Baoquan He <bhe@...hat.com>,
        Lorenzo Stoakes <lstoakes@...il.com>,
        Christoph Hellwig <hch@...radead.org>,
        Matthew Wilcox <willy@...radead.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>,
        Roman Gushchin <roman.gushchin@...ux.dev>
Subject: Re: [PATCH v3 1/3] mm: vmalloc: Avoid calling __find_vmap_area()
 twice in __vunmap()

On Thu, Dec 22, 2022 at 08:00:20PM +0100, Uladzislau Rezki (Sony) wrote:
> @@ -1825,9 +1825,8 @@ static void free_vmap_area_noflush(struct vmap_area *va)
>  	unsigned long va_start = va->va_start;
>  	unsigned long nr_lazy;
>  
> -	spin_lock(&vmap_area_lock);
> -	unlink_va(va, &vmap_area_root);
> -	spin_unlock(&vmap_area_lock);
> +	if (WARN_ON_ONCE(!list_empty(&va->list)))
> +		return;

I'd just drop this check as the function is not exported.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@....de>