linux-kernel - Re: [PATCH v2 1/3] mm: vmalloc: Avoid of calling __find_vmap_area() twise in _

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Message-ID: <Y6QbvYfvhUI3J7S+@infradead.org>
Date:   Thu, 22 Dec 2022 00:56:29 -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 v2 1/3] mm: vmalloc: Avoid of calling __find_vmap_area()
 twise in __vunmap()

A sorry.  I need more coffee, this is not the cover letter, but the
patch that introduceѕ find_unlink_vmap_area.

> -	spin_lock(&vmap_area_lock);
> -	unlink_va(va, &vmap_area_root);
> -	spin_unlock(&vmap_area_lock);
> +	if (!list_empty(&va->list)) {
> +		spin_lock(&vmap_area_lock);
> +		unlink_va(va, &vmap_area_root);
> +		spin_unlock(&vmap_area_lock);
> +	}

As mentioned before, I'd much rather move this into the callers.

> +	va = find_unlink_vmap_area((unsigned long) addr);
> +	return __remove_vm_area(va);

This can drop the va local variable now.