From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932609AbaHFR1B (ORCPT ); Wed, 6 Aug 2014 13:27:01 -0400 Received: from sf2.bxl.stone.is ([5.134.1.239]:38313 "EHLO sf2.bxl.stone.is" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754480AbaHFR04 (ORCPT ); Wed, 6 Aug 2014 13:26:56 -0400 X-Greylist: delayed 1143 seconds by postgrey-1.27 at vger.kernel.org; Wed, 06 Aug 2014 13:26:56 EDT X-No-Relay: not in my network X-No-Relay: not in my network X-No-Relay: not in my network X-No-Relay: not in my network X-No-Relay: not in my network X-No-Relay: not in my network Message-ID: <53E260D9.6030803@acm.org> Date: Wed, 06 Aug 2014 19:07:37 +0200 From: Bart Van Assche User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: David Rientjes , Andrew Morton CC: Ingo Molnar , Peter Zijlstra , "David S. Miller" , linux-kernel Subject: Re: [PATCH RESEND] spin_lock_*(): Always evaluate second argument References: <53CE1019.10708@acm.org> <20140722133716.cff957eff4eff1cc9c1d9968@linux-foundation.org> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Filter-ID: XtLePq6GTMn8G68F0EmQvdthj6rk7ohlAkaRQG+cDaLZlN3ufQ0ZRHdy43341LQ0JYRGiu4wDuX/ sGw1Y7RAsZ3WBw9ZlycipwBG3jGu9D8JBgu10R0foqIRsBJqRnurUO/XCGxJVedBWv8BXp6lSPrf oA0XngOaR5RLFk6kKY8+X6tyUZ34Ozy6TOwmaHPzFR2lHDoBQ4zwtMehH4SfWgLcNhHqvET8hkHK 4DD3CZT4SL0VvzAbTStaxE3e6xctxkHXgTSJC2+q+O2n2sPwh+CpLQk2sgUsKd5RNPNJeN3I5L/U AJH41ve/RciJD7RwcMm6IODZgOZ9Y8BEoKFU+QwAL7S6YYGupSBVbL2KnLMccBIk1Sag4dKiqCrF 8eZZsQYibGPulATAPqOguWXWenmy4p4jVbvkvQrOImHI+zH4ns3e6vWEaK66hz4t87L5hVQSL57W w8nd1cTP1twpFFTUuHOuOBA828Pfce2frIKvtUus/ypEW5W6Dw4DmSZF9OoIMWCP9bnVs5BJWbbt 5dM+m4WpRRDP6YzwkAPgQJZcv8AnfPB9HqHgcyCJwUz8oOSQKVK4yyKUlGmQMgPOfIQtTQXMrNAv J7CbCYezRVuhdlkpfoNhtgWYwB/e4S2rpoRvMJWweGFGUUnI6wOX8j4FS3UlU37B6qPMab0LB93J IFkIZaBCBQxuHnm838r53JPVY43DX2xu13bzR77n10CVt0DUeFU/MBWnkHtFiUWEyj6NsnagMRqM 8j9gdkiQLAkCbSNS+uGS3B2gbpH+CQoQ5a8OxA97GyhrhjQrc+GSwIY88rqRZEl0ZFXSwVn3 X-Report-Abuse-To: spam@sf1.bxl.stone.is X-Filter-Fingerprint: cPaH8lomer6UwsJ3BnJDysg56Hzi1baYmi2c/60G48S0VFDyP20las9Mq1v6nXmfrqKtWpHLpkE8 c09GKJn2t6TQwbo+S0UtFDS0IPuZMQ1MqRJTan78INzQLlEGX/jFRST5X0bRoOLYozD+qqgg13U4 H51jyCSmLdA2hPaiVpwYWaeThsiFlmPt/lOSmjPe8esElZg6YwCZs9Idr0AN/mqK95LAXg+Ea3Jb F9WwpaZ//Un1C5ivAWoOksRE8XtOTT9J6CK2j8j7/AJ9TNml+IbyXSJXjZjMx+Tok7jY2RMn3BMy 1LAXbQrwm8OFnukCzIqp+DPfGh5dERZ2moanphwkvo9vG3e4o6MWA4WRWjjE3nrK/nhevL/uAoHg xNXar0XzbLB8Pru9OEB7tNjak+6bpnvFzMd6SECQNf1u/wGWAJzP31LdUHDVnH0aZDcVCxO6ac9X hDc8gFJxmNF1qg== X-Originating-IP: 87.238.167.34 X-SpamExperts-Domain: stone.is X-SpamExperts-Username: 87.238.167.34 Authentication-Results: bxl.stone.is; auth=pass smtp.auth=87.238.167.34 X-SpamExperts-Outgoing-Class: ham X-SpamExperts-Outgoing-Evidence: Combined (0.07) X-Recommended-Action: accept Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/23/14 01:16, David Rientjes wrote: > On Tue, 22 Jul 2014, Andrew Morton wrote: >>> Evaluating a macro argument only if certain configuration options >>> have been selected is confusing and error-prone. Hence always >>> evaluate the second argument of spin_lock_nested() and >>> spin_lock_nest_lock(). >>> >>> An intentional side effect of this patch is that it avoids that >>> the following warning is reported for netif_addr_lock_nested() >>> when building with CONFIG_DEBUG_LOCK_ALLOC=n and with W=1: >>> >>> ... >>> >>> --- a/include/linux/spinlock.h >>> +++ b/include/linux/spinlock.h >>> @@ -197,8 +197,10 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) >>> _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ >>> } while (0) >>> #else >>> -# define raw_spin_lock_nested(lock, subclass) _raw_spin_lock(lock) >>> -# define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock) >>> +# define raw_spin_lock_nested(lock, subclass) \ >>> + ((void)(subclass), _raw_spin_lock(lock)) >>> +# define raw_spin_lock_nest_lock(lock, nest_lock) \ >>> + ((void)(nest_lock), _raw_spin_lock(lock)) >>> #endif >>> >> >> Did you try converting these to static inline functions? That should >> squish the warning and makes the code nicer instead of nastier... > > Not sure how that would be done since _raw_spin_lock isn't declared in > this scope. > > Taking a second look, however, I think the patch doesn't need to modify > raw_spin_lock_nest_lock() for the problem being reported and evaluating > the parameter of type struct lockdep_map * probably is meaningless. > > Bart, is it possible to just get away with the raw_spin_lock_nested() > change? Probably ... I will post an updated version of this patch. Bart.