Subject: Re: [PATCH net-next v11 2/4] ethtool: provide customized dim profile management

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 1 May 2024 01:55:47 -0400

On Wed, May 01, 2024 at 12:45:36PM +0800, Heng Qi wrote:
> On Wed, 1 May 2024 10:36:03 +0800, kernel test robot <[email-masked]> wrote:
> > Hi Heng,
> > 
> > kernel test robot noticed the following build warnings:
> > 
> > [auto build test WARNING on net-next/main]
> > 
> > url:    https://github.com/intel-lab-lkp/linux/commits/Heng-Qi/linux-dim-move-useful-macros-to-h-file/20240501-013413
> > base:   net-next/main
> > patch link:    https://lore.kernel.org/r/20240430173136.15807-3-hengqi%40linux.alibaba.com
> > patch subject: [PATCH net-next v11 2/4] ethtool: provide customized dim profile management
> > config: openrisc-defconfig (https://download.01.org/0day-ci/archive/20240501/[email-masked]/config)
> > compiler: or1k-linux-gcc (GCC) 13.2.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240501/[email-masked]/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <[email-masked]>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/
> > 
> > All warnings (new ones prefixed by >>):
> > 
> >    net/ethtool/coalesce.c: In function 'ethnl_update_profile':
> >    net/ethtool/coalesce.c:453:46: error: 'struct net_device' has no member named 'irq_moder'
> >      453 |         struct dim_irq_moder *irq_moder = dev->irq_moder;
> >          |                                              ^~
> >    net/ethtool/coalesce.c: At top level:
> > >> net/ethtool/coalesce.c:446:12: warning: 'ethnl_update_profile' defined but not used [-Wunused-function]
> >      446 | static int ethnl_update_profile(struct net_device *dev,
> >          |            ^~~~~~~~~~~~~~~~~~~~
> > >> net/ethtool/coalesce.c:151:12: warning: 'coalesce_put_profile' defined but not used [-Wunused-function]
> >      151 | static int coalesce_put_profile(struct sk_buff *skb, u16 attr_type,
> >          |            ^~~~~~~~~~~~~~~~~~~~
> > 
> 
> This is a known minor issue,
> to reduce the use of 'IS_ENABLED(CONFIG_DIMLIB)'
> mentioned in v10. Since the calls of ethnl_update_profile() and
> coalesce_put_profile() will only occur when IS_ENABLED(CONFIG_DIMLIB) returns
> true, the robot's warning can be ignored the code is safe.

I don't get it. The build seems to fail. How is this a minor issue?

> All NIPA test cases running on my local pass successfully on V11.
> 
> Alternatively, I remake the series to have IS_ENABLED(CONFIG_DIMLIB) back,
> up to Kuba (and others). :)
> 
> Thanks.
> 
> > 
> > vim +/ethnl_update_profile +446 net/ethtool/coalesce.c
> > 
> >    424	
> >    425	/**
> >    426	 * ethnl_update_profile - get a profile nest with child nests from userspace.
> >    427	 * @dev: netdevice to update the profile
> >    428	 * @dst: profile get from the driver and modified by ethnl_update_profile.
> >    429	 * @nests: nest attr ETHTOOL_A_COALESCE_*X_PROFILE to set profile.
> >    430	 * @extack: Netlink extended ack
> >    431	 *
> >    432	 * Layout of nests:
> >    433	 *   Nested ETHTOOL_A_COALESCE_*X_PROFILE attr
> >    434	 *     Nested ETHTOOL_A_PROFILE_IRQ_MODERATION attr
> >    435	 *       ETHTOOL_A_IRQ_MODERATION_USEC attr
> >    436	 *       ETHTOOL_A_IRQ_MODERATION_PKTS attr
> >    437	 *       ETHTOOL_A_IRQ_MODERATION_COMPS attr
> >    438	 *     ...
> >    439	 *     Nested ETHTOOL_A_PROFILE_IRQ_MODERATION attr
> >    440	 *       ETHTOOL_A_IRQ_MODERATION_USEC attr
> >    441	 *       ETHTOOL_A_IRQ_MODERATION_PKTS attr
> >    442	 *       ETHTOOL_A_IRQ_MODERATION_COMPS attr
> >    443	 *
> >    444	 * Return: 0 on success or a negative error code.
> >    445	 */
> >  > 446	static int ethnl_update_profile(struct net_device *dev,
> >    447					struct dim_cq_moder __rcu **dst,
> >    448					const struct nlattr *nests,
> >    449					struct netlink_ext_ack *extack)
> >    450	{
> >    451		int len_irq_moder = ARRAY_SIZE(coalesce_irq_moderation_policy);
> >    452		struct nlattr *tb[ARRAY_SIZE(coalesce_irq_moderation_policy)];
> >  > 453		struct dim_irq_moder *irq_moder = dev->irq_moder;
> >    454		struct dim_cq_moder *new_profile, *old_profile;
> >    455		int ret, rem, i = 0, len;
> >    456		struct nlattr *nest;
> >    457	
> >    458		if (!nests)
> >    459			return 0;
> >    460	
> >    461		if (!*dst)
> >    462			return -EOPNOTSUPP;
> >    463	
> >    464		old_profile = rtnl_dereference(*dst);
> >    465		len = NET_DIM_PARAMS_NUM_PROFILES * sizeof(*old_profile);
> >    466		new_profile = kmemdup(old_profile, len, GFP_KERNEL);
> >    467		if (!new_profile)
> >    468			return -ENOMEM;
> >    469	
> >    470		nla_for_each_nested_type(nest, ETHTOOL_A_PROFILE_IRQ_MODERATION,
> >    471					 nests, rem) {
> >    472			ret = nla_parse_nested(tb, len_irq_moder - 1, nest,
> >    473					       coalesce_irq_moderation_policy,
> >    474					       extack);
> >    475			if (ret)
> >    476				goto err_out;
> >    477	
> >    478			ret = ethnl_update_irq_moder(irq_moder, &new_profile[i].usec,
> >    479						     ETHTOOL_A_IRQ_MODERATION_USEC,
> >    480						     tb, DIM_COALESCE_USEC,
> >    481						     extack);
> >    482			if (ret)
> >    483				goto err_out;
> >    484	
> >    485			ret = ethnl_update_irq_moder(irq_moder, &new_profile[i].pkts,
> >    486						     ETHTOOL_A_IRQ_MODERATION_PKTS,
> >    487						     tb, DIM_COALESCE_PKTS,
> >    488						     extack);
> >    489			if (ret)
> >    490				goto err_out;
> >    491	
> >    492			ret = ethnl_update_irq_moder(irq_moder, &new_profile[i].comps,
> >    493						     ETHTOOL_A_IRQ_MODERATION_COMPS,
> >    494						     tb, DIM_COALESCE_COMPS,
> >    495						     extack);
> >    496			if (ret)
> >    497				goto err_out;
> >    498	
> >    499			i++;
> >    500		}
> >    501	
> >    502		rcu_assign_pointer(*dst, new_profile);
> >    503		kfree_rcu(old_profile, rcu);
> >    504	
> >    505		return 0;
> >    506	
> >    507	err_out:
> >    508		kfree(new_profile);
> >    509		return ret;
> >    510	}
> >    511	
> > 
> > -- 
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests/wiki