[dpdk-dev] [PATCH 3/8] drivers/net/e1000: Fix missing brackets

Panu Matilainen pmatilai at redhat.com
Tue Mar 1 12:02:31 CET 2016


On 02/26/2016 03:13 PM, Aaron Conole wrote:
> Hi Wenzhou,
>
> "Lu, Wenzhuo" <wenzhuo.lu at intel.com> writes:
>
>> Hi Aaron,
>>
>>
>>> -----Original Message-----
>>> From: Aaron Conole [mailto:aconole at redhat.com]
>>> Sent: Friday, February 26, 2016 2:49 AM
>>> To: dev at dpdk.org
>>> Cc: Lu, Wenzhuo; Zhang, Helin; Ananyev, Konstantin; Richardson, Bruce
>>> Subject: [PATCH 3/8] drivers/net/e1000: Fix missing brackets
>>>
>>> The register read/write mphy functions have misleading whitespace around the
>>> locked check. This cleanup merely preserves the existing functionality while
>>> improving the ready check.
>>>
>>> Signed-off-by: Aaron Conole <aconole at redhat.com>
>>> ---
>>>   drivers/net/e1000/base/e1000_phy.c | 12 ++++++------
>>>   1 file changed, 6 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/net/e1000/base/e1000_phy.c
>>> b/drivers/net/e1000/base/e1000_phy.c
>>> index d43b7ce..8642d38 100644
>>> --- a/drivers/net/e1000/base/e1000_phy.c
>>> +++ b/drivers/net/e1000/base/e1000_phy.c
>>> @@ -4153,13 +4153,13 @@ s32 e1000_read_phy_reg_mphy(struct e1000_hw
>>> *hw, u32 address, u32 *data)
>>>   	*data = E1000_READ_REG(hw, E1000_MPHY_DATA);
>>>
>>>   	/* Disable access to mPHY if it was originally disabled */
>>> -	if (locked)
>>> +	if (locked) {
>>>   		ready = e1000_is_mphy_ready(hw);
>>>   		if (!ready)
>>>   			return -E1000_ERR_PHY;
>>> -		E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL,
>>> -				E1000_MPHY_DIS_ACCESS);
>>> +	}
>>>
>>> +	E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL,
>>> E1000_MPHY_DIS_ACCESS);
>>>   	return E1000_SUCCESS;
>>>   }
>>>
>>> @@ -4218,13 +4218,13 @@ s32 e1000_write_phy_reg_mphy(struct e1000_hw
>>> *hw, u32 address, u32 data,
>>>   	E1000_WRITE_REG(hw, E1000_MPHY_DATA, data);
>>>
>>>   	/* Disable access to mPHY if it was originally disabled */
>>> -	if (locked)
>>> +	if (locked) {
>>>   		ready = e1000_is_mphy_ready(hw);
>>>   		if (!ready)
>>>   			return -E1000_ERR_PHY;
>>> -		E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL,
>>> -				E1000_MPHY_DIS_ACCESS);
>>> +	}
>>>
>>> +	E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL,
>>> E1000_MPHY_DIS_ACCESS);
>>>   	return E1000_SUCCESS;
>>>   }
>>>
>>> --
>>> 2.5.0
>> Normally we will not maintain the base code. It's just taken from kernel driver.
>> Agree with you that the whitespace is misleading. But as it's no real
>> impact. I'd like to say not a big deal, better not change it. :)
>
> Thanks for this hint. It turns out my patch is wrong. It should actually
> be this (and I've confirmed by looking at the drivers):
>
> diff --git a/drivers/net/e1000/base/e1000_phy.c b/drivers/net/e1000/base/e1000_phy.c
> index d43b7ce..ad3fd58 100644
> --- a/drivers/net/e1000/base/e1000_phy.c
> +++ b/drivers/net/e1000/base/e1000_phy.c
> @@ -4153,12 +4153,12 @@ s32 e1000_read_phy_reg_mphy(struct e1000_hw *hw, u32 address, u32 *data)
>   	*data = E1000_READ_REG(hw, E1000_MPHY_DATA);
>
>   	/* Disable access to mPHY if it was originally disabled */
> -	if (locked)
> +	if (locked) {
>   		ready = e1000_is_mphy_ready(hw);
>   		if (!ready)
>   			return -E1000_ERR_PHY;
> -		E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL,
> -				E1000_MPHY_DIS_ACCESS);
> +		E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL, E1000_MPHY_DIS_ACCESS);
> +	}
>
>   	return E1000_SUCCESS;
>   }
> @@ -4218,12 +4218,12 @@ s32 e1000_write_phy_reg_mphy(struct e1000_hw *hw, u32 address, u32 data,
>   	E1000_WRITE_REG(hw, E1000_MPHY_DATA, data);
>
>   	/* Disable access to mPHY if it was originally disabled */
> -	if (locked)
> +	if (locked) {
>   		ready = e1000_is_mphy_ready(hw);
>   		if (!ready)
>   			return -E1000_ERR_PHY;
> -		E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL,
> -				E1000_MPHY_DIS_ACCESS);
> +		E1000_WRITE_REG(hw, E1000_MPHY_ADDR_CTRL, E1000_MPHY_DIS_ACCESS);
> +	}
>
>   	return E1000_SUCCESS;
>   }
>
> I will cook up a v2 of this patch if it makes sense. It is a real bug,
> so should be fixed.

Yes, it quite clearly is a real bug and there needs to be a documented 
way of getting these things fixed. The README in the base/ directory is 
not particularly helpful, since it only says "dont touch it".

This is apparently fixed in FreeBSD codebase so fixing it would be 
"just" a matter of pulling in a newer version.

The other alternatives are either disabling the whole driver in gcc 6 
builds, or paper over the bug with warning disablers, or have everybody 
patch their packages locally to fix it, all of which just feel so stupid 
they're not alternatives, really.

OTOH the bug has been there for 2.5 years (since commit 
38db3f7f50bde45477f564783a06ac8fbd3348fa) and nobody has noticed...

Thomas, Bruce, thoughts/comments?

	- Panu -


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