Date: Mon, 30 Nov 2015 09:38:42 -0800
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>, linux-kbuild@vger.kernel.org,
        Marcelo Tosatti <mtosatti@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Boqun Feng <boqun.feng@gmail.com>
Subject: Re: [PATCH tip v5 2/5] kbuild: Add option to turn incompatible
 pointer check into error
Message-ID: <20151130173842.GV26643@linux.vnet.ibm.com>
Reply-To: paulmck@linux.vnet.ibm.com
References: <1448890711-5812-1-git-send-email-daniel.wagner@bmw-carit.de>
 <1448890711-5812-3-git-send-email-daniel.wagner@bmw-carit.de>
 <565C6A8B.8080103@bmw-carit.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <565C6A8B.8080103@bmw-carit.de>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1784
Lines: 36

On Mon, Nov 30, 2015 at 04:26:03PM +0100, Daniel Wagner wrote:
> On 11/30/2015 02:38 PM, Daniel Wagner wrote:
> > With the introduction of the simple wait API we have two very
> > similar APIs in the kernel. For example wake_up() and swake_up()
> > is only one character away. Although the compiler will warn
> > happily the wrong usage it keeps on going an even links the kernel.
> > Thomas and Peter would rather like to see early missuses reported
> > as error early on.
> > 
> > In a first attempt we tried to wrap all swait and wait calls
> > into a macro which has an compile time type assertion. The result
> > was pretty ugly and wasn't able to catch all wrong usages.
> > woken_wake_function(), autoremove_wake_function() and wake_bit_function()
> > are assigned as function pointers. Wrapping them with a macro around is
> > not possible. Prefixing them with '_' was also not a real option
> > because there some users in the kernel which do use them as well.
> > All in all this attempt looked to intrusive and too ugly.
> > 
> > An alternative is to turn the pointer type check into an error which
> > catches wrong type uses. Obviously not only the swait/wait ones. That
> > isn't a bad thing either. Though for the beginning let's introduce it
> > as options in the kernel hacking section.
> 
> The kbuild bot found one problem for allmodconfig. I just send a fix for
> it ("regmap: Fix leftover from struct reg_default to struct reg_sequence
> change").

This will result in an updated series, correct?

							Thanx, Paul

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/