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Date:   Sat, 16 Apr 2022 09:37:33 +0200 (CEST)
From:   Julia Lawall <julia.lawall@inria.fr>
To:     Alaa Mohamed <eng.alaamohamedsoliman.am@gmail.com>
cc:     outreachy@lists.linux.dev, jesse.brandeburg@intel.com,
        anthony.l.nguyen@intel.com, davem@davemloft.net, kuba@kernel.org,
        pabeni@redhat.com, intel-wired-lan@lists.osuosl.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        ira.weiny@intel.com
Subject: Re: [PATCH] intel: igb: igb_ethtool.c: Convert kmap() to
 kmap_local_page()
In-Reply-To: <20220415205307.675650-1-eng.alaamohamedsoliman.am@gmail.com>
Message-ID: <alpine.DEB.2.22.394.2204160937120.3501@hadrien>
References: <20220415205307.675650-1-eng.alaamohamedsoliman.am@gmail.com>
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On Fri, 15 Apr 2022, Alaa Mohamed wrote:

> The use of kmap() is being deprecated in favor of kmap_local_page()
> where it is feasible.

And why is it feasible here?

julia

>
> With kmap_local_page(), the mapping is per thread, CPU local and not
> globally visible.
>
> Signed-off-by: Alaa Mohamed <eng.alaamohamedsoliman.am@gmail.com>
> ---
>  drivers/net/ethernet/intel/igb/igb_ethtool.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> index 2a5782063f4c..ba93aa4ae6a0 100644
> --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> @@ -1798,14 +1798,14 @@ static int igb_check_lbtest_frame(struct igb_rx_buffer *rx_buffer,
>
>  	frame_size >>= 1;
>
> -	data = kmap(rx_buffer->page);
> +	data = kmap_local_page(rx_buffer->page);
>
>  	if (data[3] != 0xFF ||
>  	    data[frame_size + 10] != 0xBE ||
>  	    data[frame_size + 12] != 0xAF)
>  		match = false;
>
> -	kunmap(rx_buffer->page);
> +	kunmap_local(rx_buffer->page);
>
>  	return match;
>  }
> --
> 2.35.2
>
>
>