linux-kernel - Re: [PATCH v2] mm: Release a semaphore in 'get_vaddr

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Date:   Tue, 12 Dec 2017 08:50:14 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     dan.j.williams@...el.com, akpm@...ux-foundation.org,
        borntraeger@...ibm.com, dsterba@...e.com,
        gregkh@...uxfoundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v2] mm: Release a semaphore in 'get_vaddr_frames()'

On Mon 11-12-17 22:10:09, Christophe JAILLET wrote:
> A semaphore is acquired before this check, so we must release it before
> leaving.
> 
> Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>

Looks good to me now.
Acked-by: Michal Hocko <mhocko@...e.com>

Thanks

> ---
> -- Untested --
> 
> v1 -> v2: 'goto out' instead of duplicating code
> ---
>  mm/frame_vector.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> index 297c7238f7d4..c64dca6e27c2 100644
> --- a/mm/frame_vector.c
> +++ b/mm/frame_vector.c
> @@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>  	 * get_user_pages_longterm() and disallow it for filesystem-dax
>  	 * mappings.
>  	 */
> -	if (vma_is_fsdax(vma))
> -		return -EOPNOTSUPP;
> +	if (vma_is_fsdax(vma)) {
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
>  
>  	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
>  		vec->got_ref = true;
> -- 
> 2.14.1
> 

-- 
Michal Hocko
SUSE Labs