linux-kernel - Re: [PATCH] lightnvm: pblk: Fix freeing merged pages

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Date:   Fri, 24 May 2019 16:10:33 +0200
From:   Matias Bjørling <mb@...htnvm.io>
To:     Heiner Litz <hlitz@...c.edu>
Cc:     javier@...igon.com, Hans Holmberg <Hans.Holmberg@....com>,
        igor.j.konopko@...el.com, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] lightnvm: pblk: Fix freeing merged pages

On 5/15/19 2:39 AM, Heiner Litz wrote:
> bio_add_pc_page() may merge pages when a bio is padded due to a flush.
> Fix iteration over the bio to free the correct pages in case of a merge.
> 
> Signed-off-by: Heiner Litz <hlitz@...c.edu>
> ---
>   drivers/lightnvm/pblk-core.c | 18 ++++++++++--------
>   1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index 773537804319..88d61b27a9ab 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -323,14 +323,16 @@ void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int type)
>   void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
>   			 int nr_pages)
>   {
> -	struct bio_vec bv;
> -	int i;
> -
> -	WARN_ON(off + nr_pages != bio->bi_vcnt);
> -
> -	for (i = off; i < nr_pages + off; i++) {
> -		bv = bio->bi_io_vec[i];
> -		mempool_free(bv.bv_page, &pblk->page_bio_pool);
> +	struct bio_vec *bv;
> +	struct page *page;
> +	int i,e, nbv = 0;
> +
> +	for (i = 0; i < bio->bi_vcnt; i++) {
> +		bv = &bio->bi_io_vec[i];
> +		page = bv->bv_page;
> +		for (e = 0; e < bv->bv_len; e += PBLK_EXPOSED_PAGE_SIZE, nbv++)
> +			if (nbv >= off)
> +				mempool_free(page++, &pblk->page_bio_pool);
>   	}
>   }
>   
> 

Thanks Heiner. Picked up for 5.3.