From: Colin Ian King <colin.king@canonical.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>,
netdev@vger.kernel.org, kernel-janitors@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
Jose Abreu <joabreu@synopsys.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Giuseppe Cavallaro <peppe.cavallaro@st.com>,
"David S . Miller" <davem@davemloft.net>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] net: stmmac: xgmac: add missing parentheses to fix precendence error
Date: Wed, 2 Oct 2019 14:40:31 +0100 [thread overview]
Message-ID: <693a7640-68fc-9f68-8290-3542a9f02fd7@canonical.com> (raw)
In-Reply-To: <20191002133356.GP22609@kadam>
On 02/10/2019 14:33, Dan Carpenter wrote:
> On Wed, Oct 02, 2019 at 12:08:49PM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The expression !(hw_cap & XGMAC_HWFEAT_RAVSEL) >> 10 is always zero, so
>> the masking operation is incorrect. Fix this by adding the missing
>> parentheses to correctly bind the negate operator on the entire expression.
>>
>> Addresses-Coverity: ("Operands don't affect result")
>> Fixes: c2b69474d63b ("net: stmmac: xgmac: Correct RAVSEL field interpretation")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>> drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
>> index 965cbe3e6f51..2e814aa64a5c 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
>> @@ -369,7 +369,7 @@ static void dwxgmac2_get_hw_feature(void __iomem *ioaddr,
>> dma_cap->eee = (hw_cap & XGMAC_HWFEAT_EEESEL) >> 13;
>> dma_cap->atime_stamp = (hw_cap & XGMAC_HWFEAT_TSSEL) >> 12;
>> dma_cap->av = (hw_cap & XGMAC_HWFEAT_AVSEL) >> 11;
>> - dma_cap->av &= !(hw_cap & XGMAC_HWFEAT_RAVSEL) >> 10;
>> + dma_cap->av &= !((hw_cap & XGMAC_HWFEAT_RAVSEL) >> 10);
>
> There is no point to the shift at all.
I must admit I was so focused on figuring out the original intent of the
code I totally missed that optimization step. I'll send a V2.
>
> regards,
> dan carpenter
>
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next prev parent reply other threads:[~2019-10-02 13:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-02 11:08 [PATCH] net: stmmac: xgmac: add missing parentheses to fix precendence error Colin King
2019-10-02 13:33 ` Dan Carpenter
2019-10-02 13:40 ` Colin Ian King [this message]
2019-10-02 13:42 ` Dan Carpenter
2019-10-02 13:53 ` Colin Ian King
2019-10-02 14:07 ` Dan Carpenter
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