linux-kernel - Re: [PATCH 5/5] brd: Kill usage of page->index

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Message-ID: <eaa8ed55-f364-5518-0b30-3fec6bde99dc@redhat.com>
Date:   Thu, 14 Oct 2021 17:09:50 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Kent Overstreet <kent.overstreet@...il.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        akpm@...ux-foundation.org, linux-raid@...r.kernel.org,
        linux-block@...r.kernel.org, axboe@...nel.dk
Cc:     alexander.h.duyck@...ux.intel.com
Subject: Re: [PATCH 5/5] brd: Kill usage of page->index

On 13.10.21 18:00, Kent Overstreet wrote:
> As part of the struct page cleanups underway, we want to remove as much
> usage of page->mapping and page->index as possible, as frequently they
> are known from context.
> 
> In the brd code, we're never actually reading from page->index except in
> assertions, so references to it can be safely deleted.
> 
> Signed-off-by: Kent Overstreet <kent.overstreet@...il.com>
> ---
>  drivers/block/brd.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/block/brd.c b/drivers/block/brd.c
> index 58ec167aa0..0a55aed832 100644
> --- a/drivers/block/brd.c
> +++ b/drivers/block/brd.c
> @@ -72,8 +72,6 @@ static struct page *brd_lookup_page(struct brd_device *brd, sector_t sector)
>  	page = radix_tree_lookup(&brd->brd_pages, idx);
>  	rcu_read_unlock();
>  
> -	BUG_ON(page && page->index != idx);
> -
>  	return page;
>  }
>  
> @@ -108,12 +106,10 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector)
>  
>  	spin_lock(&brd->brd_lock);
>  	idx = sector >> PAGE_SECTORS_SHIFT;
> -	page->index = idx;
>  	if (radix_tree_insert(&brd->brd_pages, idx, page)) {
>  		__free_page(page);
>  		page = radix_tree_lookup(&brd->brd_pages, idx);
>  		BUG_ON(!page);
> -		BUG_ON(page->index != idx);
>  	} else {
>  		brd->brd_nr_pages++;
>  	}
> 

Reviewed-by: David Hildenbrand <david@...hat.com>

-- 
Thanks,

David / dhildenb