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Date:   Thu, 25 Jul 2019 09:46:34 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Bharath Vedartham <linux.bhar@gmail.com>
Cc:     ira.weiny@intel.com, jglisse@redhat.com,
        Matt.Sickler@daktronics.com, jhubbard@nvidia.com,
        devel@driverdev.osuosl.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] staging: kpc2000: Convert put_page to put_user_page*()
Message-ID: <20190725074634.GB15090@kroah.com>
References: <20190720173214.GA4250@bharath12345-Inspiron-5559>
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On Sat, Jul 20, 2019 at 11:02:14PM +0530, Bharath Vedartham wrote:
> For pages that were retained via get_user_pages*(), release those pages
> via the new put_user_page*() routines, instead of via put_page().
> 
> This is part a tree-wide conversion, as described in commit fc1d8e7cca2d ("mm: introduce put_user_page*(), placeholder versions").

Please line-wrap this line.

> 
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: J?r?me Glisse <jglisse@redhat.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Matt Sickler <Matt.Sickler@daktronics.com>
> Cc: devel@driverdev.osuosl.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-mm@kvack.org
> Reviewed-by: John Hubbard <jhubbard@nvidia.com>
> Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com>
> ---
> Changes since v1
>        - Improved changelog by John's suggestion.
>        - Moved logic to dirty pages below sg_dma_unmap
>        and removed PageReserved check.
> Changes since v2
>        - Added back PageResevered check as suggested by John Hubbard.
> Changes since v3
>        - Changed the commit log as suggested by John.
>        - Added John's Reviewed-By tag
> 
> ---
>  drivers/staging/kpc2000/kpc_dma/fileops.c | 17 ++++++-----------
>  1 file changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
> index 6166587..75ad263 100644
> --- a/drivers/staging/kpc2000/kpc_dma/fileops.c
> +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
> @@ -198,9 +198,7 @@ int  kpc_dma_transfer(struct dev_private_data *priv, struct kiocb *kcb, unsigned
>  	sg_free_table(&acd->sgt);
>   err_dma_map_sg:
>   err_alloc_sg_table:
> -	for (i = 0 ; i < acd->page_count ; i++){
> -		put_page(acd->user_pages[i]);
> -	}
> +	put_user_pages(acd->user_pages, acd->page_count);
>   err_get_user_pages:
>  	kfree(acd->user_pages);
>   err_alloc_userpages:
> @@ -221,16 +219,13 @@ void  transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
>  	
>  	dev_dbg(&acd->ldev->pldev->dev, "transfer_complete_cb(acd = [%p])\n", acd);
>  	
> -	for (i = 0 ; i < acd->page_count ; i++){
> -		if (!PageReserved(acd->user_pages[i])){
> -			set_page_dirty(acd->user_pages[i]);
> -		}
> -	}
> -	
>  	dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
>  	
> -	for (i = 0 ; i < acd->page_count ; i++){
> -		put_page(acd->user_pages[i]);
> +	for (i = 0; i < acd->page_count; i++) {
> +		if (!PageReserved(acd->user_pages[i]))
> +			put_user_pages_dirty(&acd->user_pages[i], 1);
> +		else
> +			put_user_page(acd->user_pages[i]);
>  	}
>  	
>  	sg_free_table(&acd->sgt);
> -- 
> 2.7.4

This patch can not be applied at all :(

Can you redo it against the latest staging-next branch and resend?

thanks,

greg k-h