From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1 Date: Thu, 24 Aug 2017 14:32:30 -0700 (PDT) Message-ID: <20170824.143230.1441873385968459116.davem@davemloft.net> References: <20170823153936.22857-1-colin.king@canonical.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: aviad.krawczyk@huawei.com, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org To: colin.king@canonical.com Return-path: In-Reply-To: <20170823153936.22857-1-colin.king@canonical.com> Sender: kernel-janitors-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Colin King Date: Wed, 23 Aug 2017 16:39:36 +0100 > From: Colin Ian King > > The comparison of hw_ioctxt.rx_buf_sz_idx == -1 is always false because > rx_buf_sz_idx is a uint16_t. Fix this by explicitly casting -1 to uint16_t. > > Detected by CoverityScan, CID#1454559 ("Operands don't affect result") > > Signed-off-by: Colin Ian King > --- > drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c b/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c > index 09dec6de8dd5..71e26070fb7f 100644 > --- a/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c > +++ b/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c > @@ -352,7 +352,7 @@ static int set_hw_ioctxt(struct hinic_hwdev *hwdev, unsigned int rq_depth, > } > } > > - if (hw_ioctxt.rx_buf_sz_idx == -1) > + if (hw_ioctxt.rx_buf_sz_idx == (uint16_t)-1) > return -EINVAL; > > hw_ioctxt.sq_depth = ilog2(sq_depth); This is really silly. The code in question is trying to convert a size (HINIC_RX_BUF_SZ) into a table index, using a loop. It should just compute this at compile time and do away with this overly confusing code. Even a switch statement would be much better and the compiler would optimize the whole away into a single assignment in the generated code.