From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kok, Auke" Subject: Re: [PATCH 1/2] [RFC] NET: Implement a standard ndev_printk family Date: Fri, 08 Jun 2007 20:06:30 -0700 Message-ID: <466A1936.7090701@intel.com> References: <20070608220007.31573.14931.stgit@localhost.localdomain> <20070608162415.1481dfec@localhost.localdomain> <4669E967.5030708@intel.com> <20070608171040.2b4a2dd7@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, jeff@garzik.org, davem@davemloft.net, arjan@linux.intel.com To: Stephen Hemminger Return-path: Received: from mga02.intel.com ([134.134.136.20]:23299 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752351AbXFIDGj (ORCPT ); Fri, 8 Jun 2007 23:06:39 -0400 In-Reply-To: <20070608171040.2b4a2dd7@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Stephen Hemminger wrote: > On Fri, 08 Jun 2007 16:42:31 -0700 > "Kok, Auke" wrote: > >> Stephen Hemminger wrote: >>>> >>>> +#define ndev_printk(kern_level, netif_level, netdev, format, arg...) \ >>>> + do { if ((netdev)->msg_enable & NETIF_MSG_##netif_level) { \ >>>> + printk(kern_level "%s: " format, \ >>>> + (netdev)->name, ## arg); } } while (0) >>> Could you make a version that doesn't evaluate the arguments twice? >> hmm you lost me there a bit; Do you want me to duplicate this code for all the >> ndev_err/ndev_info functions instead so that ndev_err doesn't direct back to >> ndev_printk? > > It is good practice in a macro to avoid potential problems with usage > by only touching the arguments once. Otherwise, something (bogus) like > ndev_printk(KERN_DEBUG, NETIF_MSG_PKTDATA, "got %d\n", > dev++, skb->len) > would increment dev twice. agreed, but > My preference would be something more like dev_printk or even use that? > You want to show both device name, and physical attachment in the message. actually these ndev_* macros are almost an exact copy of dev_printk, which is how I modeled them in the first place! See for yourself - here's the relevant snipplet from linux/device.h: 500 #define dev_printk(level, dev, format, arg...) \ 501 printk(level "%s %s: " format , dev_driver_string(dev) , (dev)->bus_id , ## arg) 502 503 #ifdef DEBUG 504 #define dev_dbg(dev, format, arg...) \ 505 dev_printk(KERN_DEBUG , dev , format , ## arg) 506 #else 507 #define dev_dbg(dev, format, arg...) do { (void)(dev); } while (0) 508 #endif 509 510 #define dev_err(dev, format, arg...) \ 511 dev_printk(KERN_ERR , dev , format , ## arg) 512 #define dev_info(dev, format, arg...) \ 513 dev_printk(KERN_INFO , dev , format , ## arg) 514 #define dev_warn(dev, format, arg...) \ 515 dev_printk(KERN_WARNING , dev , format , ## arg) 516 #define dev_notice(dev, format, arg...) \ 517 dev_printk(KERN_NOTICE , dev , format , ## arg) using dev_printk however ignores msg_enable completely and also omits netdev->name, which may even change, so for netdevices it's much less suitable, maybe only at init time. We can fix the dev_printk macro family as well, that's allright, but the need for a netdev-centric printk should be obvious: almost every netdevice driver has it's own variant :) Auke