2015-12-24 08:33:32

by Bjorn Andersson

[permalink] [raw]
Subject: [PATCH] mac80211: Make addr const in SET_IEEE80211_PERM_ADDR()

Make the addr parameter const in SET_IEEE80211_PERM_ADDR() to save
clients from having to cast away a const qualifier.

Signed-off-by: Bjorn Andersson <[email protected]>
---
include/net/mac80211.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 7c30faff245f..a6f3c9c4b7c2 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2167,7 +2167,7 @@ static inline void SET_IEEE80211_DEV(struct ieee80211_hw *hw, struct device *dev
* @hw: the &struct ieee80211_hw to set the MAC address for
* @addr: the address to set
*/
-static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, u8 *addr)
+static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, const u8 *addr)
{
memcpy(hw->wiphy->perm_addr, addr, ETH_ALEN);
}
--
2.5.0


2015-12-30 16:47:14

by Souptick Joarder

[permalink] [raw]
Subject: Re: [PATCH] mac80211: Make addr const in SET_IEEE80211_PERM_ADDR()

HI Bjorn,

On Thu, Dec 24, 2015 at 2:03 PM, Bjorn Andersson <[email protected]> wrote:
> Make the addr parameter const in SET_IEEE80211_PERM_ADDR() to save
> clients from having to cast away a const qualifier.
>
> Signed-off-by: Bjorn Andersson <[email protected]>
> ---
> include/net/mac80211.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> index 7c30faff245f..a6f3c9c4b7c2 100644
> --- a/include/net/mac80211.h
> +++ b/include/net/mac80211.h
> @@ -2167,7 +2167,7 @@ static inline void SET_IEEE80211_DEV(struct ieee80211_hw *hw, struct device *dev
> * @hw: the &struct ieee80211_hw to set the MAC address for
> * @addr: the address to set
> */
> -static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, u8 *addr)
> +static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, const u8 *addr)

I guess without const or with const doesn't make much difference here.
Correct me if I am wrong.
> {
> memcpy(hw->wiphy->perm_addr, addr, ETH_ALEN);
> }
> --
> 2.5.0
>
> --
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-Souptick

2015-12-30 17:05:37

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH] mac80211: Make addr const in SET_IEEE80211_PERM_ADDR()

On Wed, Dec 30, 2015 at 8:47 AM, Souptick Joarder <[email protected]> wrote:
>
> HI Bjorn,
>
> On Thu, Dec 24, 2015 at 2:03 PM, Bjorn Andersson <[email protected]> wrote:
> > Make the addr parameter const in SET_IEEE80211_PERM_ADDR() to save
> > clients from having to cast away a const qualifier.
> >
> > Signed-off-by: Bjorn Andersson <[email protected]>
> > ---
> > include/net/mac80211.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> > index 7c30faff245f..a6f3c9c4b7c2 100644
> > --- a/include/net/mac80211.h
> > +++ b/include/net/mac80211.h
> > @@ -2167,7 +2167,7 @@ static inline void SET_IEEE80211_DEV(struct ieee80211_hw *hw, struct device *dev
> > * @hw: the &struct ieee80211_hw to set the MAC address for
> > * @addr: the address to set
> > */
> > -static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, u8 *addr)
> > +static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, const u8 *addr)
>
> I guess without const or with const doesn't make much difference here.
> Correct me if I am wrong.

For most cases it doesn't make any difference, but in my driver I
acquire the mac address as a const u8 *. Therefor I need to cast away
the const part when calling this API.

There's an existing example of this in
drivers/net/wireless/st/cw1200/main.c line 601.


I think it's safe to assume that this API won't ever modify the passed
addr buffer, so there would be no future issues of marking the
parameter const either.

>
> > {
> > memcpy(hw->wiphy->perm_addr, addr, ETH_ALEN);
> > }
>

Regards,
Bjorn

2015-12-30 18:30:53

by Souptick Joarder

[permalink] [raw]
Subject: Re: [PATCH] mac80211: Make addr const in SET_IEEE80211_PERM_ADDR()

On Wed, Dec 30, 2015 at 10:35 PM, Bjorn Andersson <[email protected]> wrote:
> On Wed, Dec 30, 2015 at 8:47 AM, Souptick Joarder <[email protected]> wrote:
>>
>> HI Bjorn,
>>
>> On Thu, Dec 24, 2015 at 2:03 PM, Bjorn Andersson <[email protected]> wrote:
>> > Make the addr parameter const in SET_IEEE80211_PERM_ADDR() to save
>> > clients from having to cast away a const qualifier.
>> >
>> > Signed-off-by: Bjorn Andersson <[email protected]>
>> > ---
>> > include/net/mac80211.h | 2 +-
>> > 1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/include/net/mac80211.h b/include/net/mac80211.h
>> > index 7c30faff245f..a6f3c9c4b7c2 100644
>> > --- a/include/net/mac80211.h
>> > +++ b/include/net/mac80211.h
>> > @@ -2167,7 +2167,7 @@ static inline void SET_IEEE80211_DEV(struct ieee80211_hw *hw, struct device *dev
>> > * @hw: the &struct ieee80211_hw to set the MAC address for
>> > * @addr: the address to set
>> > */
>> > -static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, u8 *addr)
>> > +static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, const u8 *addr)
>>
>> I guess without const or with const doesn't make much difference here.
>> Correct me if I am wrong.
>
> For most cases it doesn't make any difference, but in my driver I
> acquire the mac address as a const u8 *. Therefor I need to cast away
> the const part when calling this API.
>
> There's an existing example of this in
> drivers/net/wireless/st/cw1200/main.c line 601.

Is the path correct ? I think path is
drivers/net/wireless/cw1200/main.c line 334

> I think it's safe to assume that this API won't ever modify the passed
> addr buffer, so there would be no future issues of marking the
> parameter const either.

I agree with you.

>
>>
>> > {
>> > memcpy(hw->wiphy->perm_addr, addr, ETH_ALEN);
>> > }
>>
>
> Regards,
> Bjorn

-Souptick

2015-12-30 20:01:58

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH] mac80211: Make addr const in SET_IEEE80211_PERM_ADDR()

On Wed, Dec 30, 2015 at 10:30 AM, Souptick Joarder <[email protected]> wrote:
> On Wed, Dec 30, 2015 at 10:35 PM, Bjorn Andersson <[email protected]> wrote:
>> On Wed, Dec 30, 2015 at 8:47 AM, Souptick Joarder <[email protected]> wrote:
>>>
>>> HI Bjorn,
>>>
>>> On Thu, Dec 24, 2015 at 2:03 PM, Bjorn Andersson <[email protected]> wrote:
>>> > Make the addr parameter const in SET_IEEE80211_PERM_ADDR() to save
>>> > clients from having to cast away a const qualifier.
>>> >
>>> > Signed-off-by: Bjorn Andersson <[email protected]>
>>> > ---
>>> > include/net/mac80211.h | 2 +-
>>> > 1 file changed, 1 insertion(+), 1 deletion(-)
>>> >
>>> > diff --git a/include/net/mac80211.h b/include/net/mac80211.h
>>> > index 7c30faff245f..a6f3c9c4b7c2 100644
>>> > --- a/include/net/mac80211.h
>>> > +++ b/include/net/mac80211.h
>>> > @@ -2167,7 +2167,7 @@ static inline void SET_IEEE80211_DEV(struct ieee80211_hw *hw, struct device *dev
>>> > * @hw: the &struct ieee80211_hw to set the MAC address for
>>> > * @addr: the address to set
>>> > */
>>> > -static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, u8 *addr)
>>> > +static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, const u8 *addr)
>>>
>>> I guess without const or with const doesn't make much difference here.
>>> Correct me if I am wrong.
>>
>> For most cases it doesn't make any difference, but in my driver I
>> acquire the mac address as a const u8 *. Therefor I need to cast away
>> the const part when calling this API.
>>
>> There's an existing example of this in
>> drivers/net/wireless/st/cw1200/main.c line 601.
>
> Is the path correct ? I think path is
> drivers/net/wireless/cw1200/main.c line 334
>

It's apparently being relocated in linux-next, and I'm not sure where
I got that line number from. But that's the example I tried to refer
to ;)

Sorry about that.

Regards,
Bjorn

>> I think it's safe to assume that this API won't ever modify the passed
>> addr buffer, so there would be no future issues of marking the
>> parameter const either.
>
> I agree with you.
>
>>
>>>
>>> > {
>>> > memcpy(hw->wiphy->perm_addr, addr, ETH_ALEN);
>>> > }
>>>
>>
>> Regards,
>> Bjorn
>
> -Souptick