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From:   Uladzislau Rezki <urezki@gmail.com>
Date:   Thu, 22 Dec 2022 15:41:29 +0100
To:     Christoph Hellwig <hch@infradead.org>
Cc:     "Uladzislau Rezki (Sony)" <urezki@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        LKML <linux-kernel@vger.kernel.org>, Baoquan He <bhe@redhat.com>,
        Lorenzo Stoakes <lstoakes@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
        Roman Gushchin <roman.gushchin@linux.dev>
Subject: Re: [PATCH v2 1/3] mm: vmalloc: Avoid of calling __find_vmap_area()
 twise in __vunmap()
Message-ID: <Y6RsmcvZ8Ru211Jk@pc636>
References: <20221221174454.1085130-1-urezki@gmail.com>
 <Y6QbvYfvhUI3J7S+@infradead.org>
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> A sorry.  I need more coffee, this is not the cover letter, but the
> patch that introduceѕ find_unlink_vmap_area.
> 
Sorry. I should post it with a cover latter to make it less confusing.

> > -	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.
> 
Agree. There is only one caller, it is the free_vmap_block().
Will fix in the v3.

> > +	va = find_unlink_vmap_area((unsigned long) addr);
> > +	return __remove_vm_area(va);
> 
> This can drop the va local variable now.
>
Do you mean like:

struct vm_struct *remove_vm_area(const void *addr)
{
    might_sleep();
    return __remove_vm_area(
        find_unlink_vmap_area((unsigned long) addr));
}

?

Thanks for review!

--
Uladzislau Rezki