Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752997AbcCTQgC (ORCPT ); Sun, 20 Mar 2016 12:36:02 -0400 Received: from mail-pf0-f171.google.com ([209.85.192.171]:35808 "EHLO mail-pf0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751159AbcCTQfz (ORCPT ); Sun, 20 Mar 2016 12:35:55 -0400 Message-ID: <1458491752.10868.4.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: [PATCH] lan78xx: Protect runtime_auto check by #ifdef CONFIG_PM From: Eric Dumazet To: Geert Uytterhoeven Cc: Woojung Huh , Microchip Linux Driver Support , "David S. Miller" , Guenter Roeck , "Rafael J. Wysocki" , netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Date: Sun, 20 Mar 2016 09:35:52 -0700 In-Reply-To: <1458470636-18986-1-git-send-email-geert@linux-m68k.org> References: <1458470636-18986-1-git-send-email-geert@linux-m68k.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1835 Lines: 48 On Sun, 2016-03-20 at 11:43 +0100, Geert Uytterhoeven wrote: > If CONFIG_PM=n: > > drivers/net/usb/lan78xx.c: In function ‘lan78xx_get_stats64’: > drivers/net/usb/lan78xx.c:3274: error: ‘struct dev_pm_info’ has no member named ‘runtime_auto’ > > If PM is disabled, the runtime_auto flag is not available, but auto > suspend is not enabled anyway. Hence protect the check for runtime_auto > by #ifdef CONFIG_PM to fix this. > > Fixes: a59f8c5b048dc938 ("lan78xx: add ndo_get_stats64") > Reported-by: Guenter Roeck > Signed-off-by: Geert Uytterhoeven > --- > Alternatively, we can add a dev_pm_runtime_auto_is_enabled() wrapper to > include/linux/pm.h, which always return false if CONFIG_PM is disabled. > > The only other user in non-core code (drivers/usb/core/sysfs.c) has a > big #ifdef CONFIG_PM check around all PM-related code. > > Thoughts? > --- > drivers/net/usb/lan78xx.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c > index d36d5ebf37f355f2..7b9ac47b2ecf9905 100644 > --- a/drivers/net/usb/lan78xx.c > +++ b/drivers/net/usb/lan78xx.c > @@ -3271,7 +3271,9 @@ struct rtnl_link_stats64 *lan78xx_get_stats64(struct net_device *netdev, > * periodic reading from HW will prevent from entering USB auto suspend. > * if autosuspend is disabled, read from HW. > */ > +#ifdef CONFIG_PM > if (!dev->udev->dev.power.runtime_auto) > +#endif > lan78xx_update_stats(dev); > > mutex_lock(&dev->stats.access_lock); Note that a ndo_get_stat64() handler is not allowed to sleep, so the mutex_lock() is not wise... Historically /proc/net/dev handler but also bonding ndo_get_stats() used RCU or a rwlock or a spinlock. So a complete fix would need to get rid of this mutex as well.