Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [net-next PATCH 1/2] mlxsw: spectrum_kvdl: use div_u64() for
 64-bit division
To:     Arnd Bergmann <arnd@arndb.de>, Jiri Pirko <jiri@mellanox.com>,
        Ido Schimmel <idosch@mellanox.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Wei Yongjun <weiyongjun1@huawei.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20180223131540.1065413-1-arnd@arndb.de>
From:   Arkadi Sharshevsky <arkadis@mellanox.com>
Message-ID: <7de58656-c772-c13b-5a35-b6065adc2128@mellanox.com>
Date:   Sun, 25 Feb 2018 12:04:10 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.4.0
MIME-Version: 1.0
In-Reply-To: <20180223131540.1065413-1-arnd@arndb.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Received-SPF: None (protection.outlook.com: mellanox.com does not designate
 permitted sender hosts)
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Feb 2018 10:04:19.1187
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 6ecf822b-d11c-4d60-ee28-08d57c372364
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: a652971c-7d2e-4d9b-a6a4-d149256f461b
X-MS-Exchange-Transport-CrossTenantHeadersStamped: HE1PR0501MB2459
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 02/23/2018 03:15 PM, Arnd Bergmann wrote:
> Calculating the number of entries now uses 64-bit arithmetic that
> causes a link error on 32-bit architectures:
> 
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.o: In function `mlxsw_sp_kvdl_init':
> spectrum_kvdl.c:(.text+0x51c): undefined reference to `__aeabi_uldivmod'
> 
> We could probably use a 32-bit division here as before, but since this is
> not in a performance critical path, div_u64() seems cleaner here.
> 
> Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> index d27fa57ad3c3..6fd701db90c9 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> @@ -278,7 +278,7 @@ static int mlxsw_sp_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
>  		resource_size = info->end_index - info->start_index + 1;
>  	}
>  
> -	nr_entries = resource_size / info->alloc_size;
> +	nr_entries = div_u64(resource_size, info->alloc_size);
>  	usage_size = BITS_TO_LONGS(nr_entries) * sizeof(unsigned long);
>  	part = kzalloc(sizeof(*part) + usage_size, GFP_KERNEL);
>  	if (!part)
> 

Acked-by: Arkadi Sharshevsky <arkadis@mellanox.com>