Re: [PATCH v8 bpf] xsk: fix immature cq descriptor production

[kernel test robot <lkp@intel.com>]

Hi Maciej,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Maciej-Fijalkowski/xsk-fix-immature-cq-descriptor-production/20250903-060850
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master
patch link:    https://lore.kernel.org/r/20250902220613.2331265-1-maciej.fijalkowski%40intel.com
patch subject: [PATCH v8 bpf] xsk: fix immature cq descriptor production
config: riscv-randconfig-001-20250903 (https://download.01.org/0day-ci/archive/20250903/202509031029.iL7rCVvQ-lkp@intel.com/config)
compiler: riscv32-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250903/202509031029.iL7rCVvQ-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509031029.iL7rCVvQ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   net/xdp/xsk.c: In function 'xsk_cq_submit_addr_locked':
>> net/xdp/xsk.c:572:38: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
     xskq_prod_write_addr(pool->cq, idx, (u64)skb_shinfo(skb)->destructor_arg);
                                         ^
   net/xdp/xsk.c: In function 'xsk_set_destructor_arg':
>> net/xdp/xsk.c:625:36: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     skb_shinfo(skb)->destructor_arg = (void *)addr;
                                       ^


vim +572 net/xdp/xsk.c

   560	
   561	static void xsk_cq_submit_addr_locked(struct xsk_buff_pool *pool,
   562					      struct sk_buff *skb)
   563	{
   564		struct xsk_addr_node *pos, *tmp;
   565		u32 descs_processed = 0;
   566		unsigned long flags;
   567		u32 idx;
   568	
   569		spin_lock_irqsave(&pool->cq_lock, flags);
   570		idx = xskq_get_prod(pool->cq);
   571	
 > 572		xskq_prod_write_addr(pool->cq, idx, (u64)skb_shinfo(skb)->destructor_arg);
   573		descs_processed++;
   574	
   575		if (unlikely(XSKCB(skb)->num_descs > 1)) {
   576			list_for_each_entry_safe(pos, tmp, &XSKCB(skb)->addrs_list, addr_node) {
   577				xskq_prod_write_addr(pool->cq, idx + descs_processed,
   578						     pos->addr);
   579				descs_processed++;
   580				list_del(&pos->addr_node);
   581				kmem_cache_free(xsk_tx_generic_cache, pos);
   582			}
   583		}
   584		xskq_prod_submit_n(pool->cq, descs_processed);
   585		spin_unlock_irqrestore(&pool->cq_lock, flags);
   586	}
   587	
   588	static void xsk_cq_cancel_locked(struct xsk_buff_pool *pool, u32 n)
   589	{
   590		unsigned long flags;
   591	
   592		spin_lock_irqsave(&pool->cq_lock, flags);
   593		xskq_prod_cancel_n(pool->cq, n);
   594		spin_unlock_irqrestore(&pool->cq_lock, flags);
   595	}
   596	
   597	static void xsk_inc_num_desc(struct sk_buff *skb)
   598	{
   599		XSKCB(skb)->num_descs++;
   600	}
   601	
   602	static u32 xsk_get_num_desc(struct sk_buff *skb)
   603	{
   604		return XSKCB(skb)->num_descs;
   605	}
   606	
   607	static void xsk_destruct_skb(struct sk_buff *skb)
   608	{
   609		struct xsk_tx_metadata_compl *compl = &skb_shinfo(skb)->xsk_meta;
   610	
   611		if (compl->tx_timestamp) {
   612			/* sw completion timestamp, not a real one */
   613			*compl->tx_timestamp = ktime_get_tai_fast_ns();
   614		}
   615	
   616		xsk_cq_submit_addr_locked(xdp_sk(skb->sk)->pool, skb);
   617		sock_wfree(skb);
   618	}
   619	
   620	static void xsk_set_destructor_arg(struct sk_buff *skb, u64 addr)
   621	{
   622		BUILD_BUG_ON(sizeof(struct xsk_addr_head) > sizeof(skb->cb));
   623		INIT_LIST_HEAD(&XSKCB(skb)->addrs_list);
   624		XSKCB(skb)->num_descs = 0;
 > 625		skb_shinfo(skb)->destructor_arg = (void *)addr;
   626	}
   627	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki