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 14:53:17 +0100 [thread overview]
Message-ID: <a995eee6-5b26-f9a9-4d6a-5533da050a3b@canonical.com> (raw)
In-Reply-To: <20191002134238.GP29696@kadam>
On 02/10/2019 14:42, Dan Carpenter wrote:
> On Wed, Oct 02, 2019 at 04:33:57PM +0300, 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.
>
> Sorry I meant to say it should be a bitwise NOT, right? I was just
> looking at some other dma_cap stuff that did this same thing... I can't
> find it now...
In drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c it is being used like
a boolean and not a bitmask'd value:
if (!priv->dma_cap.av)
so the original logic is to do boolean flag merging rather than bit-wise
logic.
>
> regards,
> dan carpenter
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-10-02 13:53 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
2019-10-02 13:42 ` Dan Carpenter
2019-10-02 13:53 ` Colin Ian King [this message]
2019-10-02 14:07 ` Dan Carpenter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a995eee6-5b26-f9a9-4d6a-5533da050a3b@canonical.com \
--to=colin.king@canonical.com \
--cc=alexandre.torgue@st.com \
--cc=dan.carpenter@oracle.com \
--cc=davem@davemloft.net \
--cc=joabreu@synopsys.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-stm32@st-md-mailman.stormreply.com \
--cc=mcoquelin.stm32@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=peppe.cavallaro@st.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).