Date:   Wed, 22 Dec 2021 13:03:56 +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,
        ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org,
        john.fastabend@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH] sfc: Check null pointer of rx_queue->page_ring
Message-ID: <20211222130356.xlzmhoyexrnctkrs@gmail.com>
Mail-Followup-To: Jiasheng Jiang <jiasheng@iscas.ac.cn>,
        ecree.xilinx@gmail.com, davem@davemloft.net, kuba@kernel.org,
        ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org,
        john.fastabend@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org
References: <20211220135603.954944-1-jiasheng@iscas.ac.cn>
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On Mon, Dec 20, 2021 at 09:56:03PM +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/rx_common.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/sfc/rx_common.c b/drivers/net/ethernet/sfc/rx_common.c
> index 68fc7d317693..0983abc0cc5f 100644
> --- a/drivers/net/ethernet/sfc/rx_common.c
> +++ b/drivers/net/ethernet/sfc/rx_common.c
> @@ -150,7 +150,10 @@ static void efx_init_rx_recycle_ring(struct efx_rx_queue *rx_queue)
>  					    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;
>  }
>  
>  static void efx_fini_rx_recycle_ring(struct efx_rx_queue *rx_queue)
> -- 
> 2.25.1