Re: Please add 98fb1ffd8154890d7051750e61ff5548c3ee2ab2

[Richard Weinberger <richard@nod.at>]

CC'in patch authors.

Am 28.09.2015 um 15:29 schrieb Luis Henriques:
> On Tue, Sep 15, 2015 at 04:48:07PM +0200, Richard Weinberger wrote:
>> Hi!
>>
>> Can you please add this commit to stable?
>> commit 98fb1ffd8154890d7051750e61ff5548c3ee2ab2
>> Author: Kevin Cernekee <cernekee@chromium.org>
>> Date:   Wed Apr 22 09:30:53 2015 -0300
>>
>>     UBI: block: Add missing cache flushes
>>
>> The fix affects all kernels >= v3.15.
>>
> 
> I was trying to apply this commit to 3.16, but it requires a backport.
> Could you please confirm the following backport is correct?  It can
> probably be applied to other stable kernels, but I haven't check.
> 
> Cheers,
> --
> Lu�s
> 
> From e781e504616d2652e9fc11f6536dd8be221298f9 Mon Sep 17 00:00:00 2001
> From: Kevin Cernekee <cernekee@chromium.org>
> Date: Wed, 22 Apr 2015 09:30:53 -0300
> Subject: [PATCH] UBI: block: Add missing cache flushes
> 
> commit 98fb1ffd8154890d7051750e61ff5548c3ee2ab2 upstream.
> 
> Block drivers are responsible for calling flush_dcache_page() on each
> BIO request. This operation keeps the I$ coherent with the D$ on
> architectures that don't have hardware coherency support. Without this
> flush, random crashes are seen when executing user programs from an ext4
> filesystem backed by a ubiblock device.
> 
> This patch is based on the change implemented in commit 2d4dc890b5c8
> ("block: add helpers to run flush_dcache_page() against a bio and a
> request's pages").
> 
> Fixes: 9d54c8a33eec ("UBI: R/O block driver on top of UBI volumes")
> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> [ luis: backported to 3.16: adjusted context ]
> Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
> ---
>  drivers/mtd/ubi/block.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
> index 8457df7ec5af..d3fbda7eae98 100644
> --- a/drivers/mtd/ubi/block.c
> +++ b/drivers/mtd/ubi/block.c
> @@ -275,6 +275,7 @@ static void ubiblock_do_work(struct work_struct *work)
>  		spin_unlock_irq(rq->queue_lock);
>  		res = do_ubiblock_request(dev, req);
>  		spin_lock_irq(rq->queue_lock);
> +		rq_flush_dcache_pages(req);
>  
>  		/*
>  		 * If we're done with this request,
>