Date:   Wed, 22 Dec 2021 13:04:56 +0000
From:   Martin Habets <habetsm.xilinx@gmail.com>
To:     Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc:     ecree.xilinx@gmail.com, davem@davemloft.net, kuba@kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sfc: falcon: Check null pointer of rx_queue->page_ring
Message-ID: <20211222130456.3lbrgx3p47fzjnzi@gmail.com>
Mail-Followup-To: Jiasheng Jiang <jiasheng@iscas.ac.cn>,
        ecree.xilinx@gmail.com, davem@davemloft.net, kuba@kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20211220140344.978408-1-jiasheng@iscas.ac.cn>
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On Mon, Dec 20, 2021 at 10:03:44PM +0800, Jiasheng Jiang wrote:
> Because of the possible failure of the kcalloc, it should be better to
> set rx_queue->page_ptr_mask to 0 when it happens in order to maintain
> the consistency.
> 
> Fixes: 5a6681e22c14 ("sfc: separate out SFC4000 ("Falcon") support into new sfc-falcon driver")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>

Acked-by: Martin Habets <habetsm.xilinx@gmail.com>

> ---
>  drivers/net/ethernet/sfc/falcon/rx.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/sfc/falcon/rx.c b/drivers/net/ethernet/sfc/falcon/rx.c
> index 966f13e7475d..11a6aee852e9 100644
> --- a/drivers/net/ethernet/sfc/falcon/rx.c
> +++ b/drivers/net/ethernet/sfc/falcon/rx.c
> @@ -728,7 +728,10 @@ static void ef4_init_rx_recycle_ring(struct ef4_nic *efx,
>  					    efx->rx_bufs_per_page);
>  	rx_queue->page_ring = kcalloc(page_ring_size,
>  				      sizeof(*rx_queue->page_ring), GFP_KERNEL);
> -	rx_queue->page_ptr_mask = page_ring_size - 1;
> +	if (!rx_queue->page_ring)
> +		rx_queue->page_ptr_mask = 0;
> +	else
> +		rx_queue->page_ptr_mask = page_ring_size - 1;
>  }
>  
>  void ef4_init_rx_queue(struct ef4_rx_queue *rx_queue)
> -- 
> 2.25.1