From: Leandro Coutinho <lescoutinhovr@gmail.com>
To: Michael Walle <michael@walle.cc>
Cc: netdev@vger.kernel.org
Subject: Re: net: intel/e1000e/netdev.c __ew32_prepare parameter not used?
Date: Tue, 3 Aug 2021 10:15:44 -0300 [thread overview]
Message-ID: <CAN6UTawJCj0O-oXSwGoVxjii9JTJ484UKXZzYnqPW1L7JB=jJA@mail.gmail.com> (raw)
In-Reply-To: <20210803085032.8834-1-michael@walle.cc>
On Tue, Aug 3, 2021 at 5:50 AM Michael Walle <michael@walle.cc> wrote:
>
> Hi,
>
> > It seems the parameter `*hw` is not used.
> > Although I didn't find where `FWSM` is defined.
> >
> > Should it be removed? Or is the parameter really needed?
> >
> > static void __ew32_prepare(struct e1000_hw *hw)
> > {
> > s32 i = E1000_ICH_FWSM_PCIM2PCI_COUNT;
> >
> > while ((er32(FWSM) & E1000_ICH_FWSM_PCIM2PCI) && --i)
> > udelay(50);
> > }
>
> If you have a look at the definition of er32() (which is a macro and
> is defined in e1000.h, you'll see that the hw parameter is used
> there without being a parameter of the macro itself. Thus if you'd
> rename the parameter you'd get a build error.Not really the best
> code to look at when you want to learn coding, because that's an
> example how not to do things, IMHO.
>
> -michael
Thank you very much Michael! =)
er32 is defined as:
#define er32(reg) __er32(hw, E1000_##reg)
That's why I didn't find any definition for `FWSM` ... because of the
token concatenation https://gcc.gnu.org/onlinedocs/cpp/Concatenation.html
I think this way it would be more clear:
#define er32(hw, reg) __er32(hw, reg)
I don't know if they did it that way just to avoid typing, or if there is some
other reason.
That is one advantage of Rust: macros have an ! at the end, eg: println!
So you can easily distinguish macros from functions.
prev parent reply other threads:[~2021-08-03 13:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-02 14:55 net: intel/e1000e/netdev.c __ew32_prepare parameter not used? Leandro Coutinho
2021-08-03 8:50 ` Michael Walle
2021-08-03 13:15 ` Leandro Coutinho [this message]
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