Re: [PATCH v1 1/5] riscv/cmpxchg: Deduplicate xchg() asm functions

[kernel test robot]

Hi Leonardo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 610a9b8f49fbcf1100716370d3b5f6f884a2835a]

url:    https://github.com/intel-lab-lkp/linux/commits/Leonardo-Bras/riscv-cmpxchg-Deduplicate-xchg-asm-functions/20240104-003501
base:   610a9b8f49fbcf1100716370d3b5f6f884a2835a
patch link:    https://lore.kernel.org/r/20240103163203.72768-3-leobras%40redhat.com
patch subject: [PATCH v1 1/5] riscv/cmpxchg: Deduplicate xchg() asm functions
config: riscv-randconfig-r111-20240112 (https://download.01.org/0day-ci/archive/20240113/202401131438.f8SELM0W-lkp@xxxxxxxxx/config)
compiler: clang version 18.0.0git (https://github.com/llvm/llvm-project 9bde5becb44ea071f5e1fa1f5d4071dc8788b18c)
reproduce: (https://download.01.org/0day-ci/archive/20240113/202401131438.f8SELM0W-lkp@xxxxxxxxx/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 <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401131438.f8SELM0W-lkp@xxxxxxxxx/

sparse warnings: (new ones prefixed by >>)
>> net/ipv4/tcp_cong.c:300:24: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected struct tcp_congestion_ops const [noderef] __rcu *__new @@     got struct tcp_congestion_ops *[assigned] ca @@
   net/ipv4/tcp_cong.c:300:24: sparse:     expected struct tcp_congestion_ops const [noderef] __rcu *__new
   net/ipv4/tcp_cong.c:300:24: sparse:     got struct tcp_congestion_ops *[assigned] ca
   net/ipv4/tcp_cong.c:300:22: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct tcp_congestion_ops const *prev @@     got struct tcp_congestion_ops const [noderef] __rcu * @@
   net/ipv4/tcp_cong.c:300:22: sparse:     expected struct tcp_congestion_ops const *prev
   net/ipv4/tcp_cong.c:300:22: sparse:     got struct tcp_congestion_ops const [noderef] __rcu *
   net/ipv4/tcp_cong.c: note: in included file (through include/linux/module.h):
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true

vim +300 net/ipv4/tcp_cong.c

317a76f9a44b43 Stephen Hemminger 2005-06-23  281  
317a76f9a44b43 Stephen Hemminger 2005-06-23  282  /* Used by sysctl to change default congestion control */
6670e152447732 Stephen Hemminger 2017-11-14  283  int tcp_set_default_congestion_control(struct net *net, const char *name)
317a76f9a44b43 Stephen Hemminger 2005-06-23  284  {
317a76f9a44b43 Stephen Hemminger 2005-06-23  285  	struct tcp_congestion_ops *ca;
6670e152447732 Stephen Hemminger 2017-11-14  286  	const struct tcp_congestion_ops *prev;
6670e152447732 Stephen Hemminger 2017-11-14  287  	int ret;
317a76f9a44b43 Stephen Hemminger 2005-06-23  288  
6670e152447732 Stephen Hemminger 2017-11-14  289  	rcu_read_lock();
6670e152447732 Stephen Hemminger 2017-11-14  290  	ca = tcp_ca_find_autoload(net, name);
6670e152447732 Stephen Hemminger 2017-11-14  291  	if (!ca) {
6670e152447732 Stephen Hemminger 2017-11-14  292  		ret = -ENOENT;
0baf26b0fcd74b Martin KaFai Lau  2020-01-08  293  	} else if (!bpf_try_module_get(ca, ca->owner)) {
6670e152447732 Stephen Hemminger 2017-11-14  294  		ret = -EBUSY;
8d432592f30fcc Jonathon Reinhart 2021-05-01  295  	} else if (!net_eq(net, &init_net) &&
8d432592f30fcc Jonathon Reinhart 2021-05-01  296  			!(ca->flags & TCP_CONG_NON_RESTRICTED)) {
8d432592f30fcc Jonathon Reinhart 2021-05-01  297  		/* Only init netns can set default to a restricted algorithm */
8d432592f30fcc Jonathon Reinhart 2021-05-01  298  		ret = -EPERM;
6670e152447732 Stephen Hemminger 2017-11-14  299  	} else {
6670e152447732 Stephen Hemminger 2017-11-14 @300  		prev = xchg(&net->ipv4.tcp_congestion_control, ca);
6670e152447732 Stephen Hemminger 2017-11-14  301  		if (prev)
0baf26b0fcd74b Martin KaFai Lau  2020-01-08  302  			bpf_module_put(prev, prev->owner);
317a76f9a44b43 Stephen Hemminger 2005-06-23  303  
6670e152447732 Stephen Hemminger 2017-11-14  304  		ca->flags |= TCP_CONG_NON_RESTRICTED;
317a76f9a44b43 Stephen Hemminger 2005-06-23  305  		ret = 0;
317a76f9a44b43 Stephen Hemminger 2005-06-23  306  	}
6670e152447732 Stephen Hemminger 2017-11-14  307  	rcu_read_unlock();
317a76f9a44b43 Stephen Hemminger 2005-06-23  308  
317a76f9a44b43 Stephen Hemminger 2005-06-23  309  	return ret;
317a76f9a44b43 Stephen Hemminger 2005-06-23  310  }
317a76f9a44b43 Stephen Hemminger 2005-06-23  311  

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