linux-kernel - Re: [PATCH v1] xen/pvcalls: free active map buffer on pvcalls_front_free

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Date:   Thu, 22 Dec 2022 15:14:50 -0800 (PST)
From:   Stefano Stabellini <sstabellini@...nel.org>
To:     Oleksii Moisieiev <Oleksii_Moisieiev@...m.com>
cc:     "sstabellini@...nel.org" <sstabellini@...nel.org>,
        Juergen Gross <jgross@...e.com>,
        Oleksandr Tyshchenko <Oleksandr_Tyshchenko@...m.com>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] xen/pvcalls: free active map buffer on
 pvcalls_front_free_map

On Tue, 20 Dec 2022, Oleksii Moisieiev wrote:
> Data buffer for active map is allocated in alloc_active_ring and freed
> in free_active_ring function, which is used only for the error
> cleanup. pvcalls_front_release is calling pvcalls_front_free_map which
> ends foreign access for this buffer, but doesn't free allocated pages.
> Call free_active_ring to clean all allocated resources.
> 
> Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@...m.com>

Reviewed-by: Stefano Stabellini <sstabellini@...nel.org>


> ---
>  drivers/xen/pvcalls-front.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> index 1826e8e67125..9b569278788a 100644
> --- a/drivers/xen/pvcalls-front.c
> +++ b/drivers/xen/pvcalls-front.c
> @@ -225,6 +225,8 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static void free_active_ring(struct sock_mapping *map);
> +
>  static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
>  				   struct sock_mapping *map)
>  {
> @@ -240,7 +242,7 @@ static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
>  	for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
>  		gnttab_end_foreign_access(map->active.ring->ref[i], NULL);
>  	gnttab_end_foreign_access(map->active.ref, NULL);
> -	free_page((unsigned long)map->active.ring);
> +	free_active_ring(map);
>  
>  	kfree(map);
>  }
> -- 
> 2.25.1
>