Subject: Re: linux-next: build failure after merge of the akpm tree

From: Haren Myneni <[email-masked]>
Date: Wed, 22 Apr 2020 11:33:59 -0700

Thanks for fixing. Tested with this patch and 7fe021a3f1c9 ("kernel: better document the use_mm/unuse_mm API contract"). 

Acked-by: Haren Myneni <[email-masked]>

On 4/21/20 11:39 PM, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the akpm tree, today's linux-next build (powerpc
> ppc64_defconfig) failed like this:
> 
> arch/powerpc/platforms/powernv/vas-fault.c: In function 'update_csb':
> arch/powerpc/platforms/powernv/vas-fault.c:130:2: error: implicit declaration of function 'use_mm' [-Werror=implicit-function-declaration]
>   130 |  use_mm(window->mm);
>       |  ^~~~~~
> arch/powerpc/platforms/powernv/vas-fault.c:142:2: error: implicit declaration of function 'unuse_mm' [-Werror=implicit-function-declaration]
>   142 |  unuse_mm(window->mm);
>       |  ^~~~~~~~
> 
> Caused by commit
> 
>   7fe021a3f1c9 ("kernel: better document the use_mm/unuse_mm API contract")
> 
> interacting with commit
> 
>   c96c4436aba4 ("powerpc/vas: Update CSB and notify process for fault CRBs")
> 
> from the powerpc tree.
> 
> I added the following patch for today:
> 
> From: Stephen Rothwell <[email-masked]>
> Date: Wed, 22 Apr 2020 16:35:23 +1000
> Subject: [PATCH] powerpc/vas: fix up for {un}use_mm() rename
> 
> Signed-off-by: Stephen Rothwell <[email-masked]>
> ---
>  arch/powerpc/platforms/powernv/vas-fault.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/vas-fault.c b/arch/powerpc/platforms/powernv/vas-fault.c
> index 25db70be4c9c..266a6ca5e15e 100644
> --- a/arch/powerpc/platforms/powernv/vas-fault.c
> +++ b/arch/powerpc/platforms/powernv/vas-fault.c
> @@ -127,7 +127,7 @@ static void update_csb(struct vas_window *window,
>  		return;
>  	}
>  
> -	use_mm(window->mm);
> +	kthread_use_mm(window->mm);
>  	rc = copy_to_user(csb_addr, &csb, sizeof(csb));
>  	/*
>  	 * User space polls on csb.flags (first byte). So add barrier
> @@ -139,7 +139,7 @@ static void update_csb(struct vas_window *window,
>  		smp_mb();
>  		rc = copy_to_user(csb_addr, &csb, sizeof(u8));
>  	}
> -	unuse_mm(window->mm);
> +	kthread_unuse_mm(window->mm);
>  	put_task_struct(tsk);
>  
>  	/* Success */
>