Re: [PATCH net-next] sock: make SKB_FRAG_PAGE_ORDER equal to PAGE_ALLOC_COSTLY_ORDER

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

Hi Yajun,

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/Yajun-Deng/sock-make-SKB_FRAG_PAGE_ORDER-equal-to-PAGE_ALLOC_COSTLY_ORDER/20241217-185748
base:   net-next/main
patch link:    https://lore.kernel.org/r/20241217105659.2215649-1-yajun.deng%40linux.dev
patch subject: [PATCH net-next] sock: make SKB_FRAG_PAGE_ORDER equal to PAGE_ALLOC_COSTLY_ORDER
config: openrisc-randconfig-r122-20241220 (https://download.01.org/0day-ci/archive/20241221/202412210700.fAOJ9ocm-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20241221/202412210700.fAOJ9ocm-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/202412210700.fAOJ9ocm-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   net/core/sock.c:2496:9: sparse: sparse: context imbalance in 'sk_clone_lock' - wrong count at exit
   net/core/sock.c:2500:6: sparse: sparse: context imbalance in 'sk_free_unlock_clone' - unexpected unlock
>> net/core/sock.c:3044:49: sparse: sparse: cast truncates bits from constant value (10000 becomes 0)

vim +3044 net/core/sock.c

5640f7685831e08 Eric Dumazet 2012-09-23  3013  
400dfd3ae899849 Eric Dumazet 2013-10-17  3014  /**
400dfd3ae899849 Eric Dumazet 2013-10-17  3015   * skb_page_frag_refill - check that a page_frag contains enough room
400dfd3ae899849 Eric Dumazet 2013-10-17  3016   * @sz: minimum size of the fragment we want to get
400dfd3ae899849 Eric Dumazet 2013-10-17  3017   * @pfrag: pointer to page_frag
82d5e2b8b466d5b Eric Dumazet 2014-09-08  3018   * @gfp: priority for memory allocation
400dfd3ae899849 Eric Dumazet 2013-10-17  3019   *
400dfd3ae899849 Eric Dumazet 2013-10-17  3020   * Note: While this allocator tries to use high order pages, there is
400dfd3ae899849 Eric Dumazet 2013-10-17  3021   * no guarantee that allocations succeed. Therefore, @sz MUST be
400dfd3ae899849 Eric Dumazet 2013-10-17  3022   * less or equal than PAGE_SIZE.
400dfd3ae899849 Eric Dumazet 2013-10-17  3023   */
d9b2938aabf757d Eric Dumazet 2014-08-27  3024  bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp)
5640f7685831e08 Eric Dumazet 2012-09-23  3025  {
5640f7685831e08 Eric Dumazet 2012-09-23  3026  	if (pfrag->page) {
fe896d1878949ea Joonsoo Kim  2016-03-17  3027  		if (page_ref_count(pfrag->page) == 1) {
5640f7685831e08 Eric Dumazet 2012-09-23  3028  			pfrag->offset = 0;
5640f7685831e08 Eric Dumazet 2012-09-23  3029  			return true;
5640f7685831e08 Eric Dumazet 2012-09-23  3030  		}
400dfd3ae899849 Eric Dumazet 2013-10-17  3031  		if (pfrag->offset + sz <= pfrag->size)
5640f7685831e08 Eric Dumazet 2012-09-23  3032  			return true;
5640f7685831e08 Eric Dumazet 2012-09-23  3033  		put_page(pfrag->page);
5640f7685831e08 Eric Dumazet 2012-09-23  3034  	}
5640f7685831e08 Eric Dumazet 2012-09-23  3035  
5640f7685831e08 Eric Dumazet 2012-09-23  3036  	pfrag->offset = 0;
af87ed7a96a9372 Yajun Deng   2024-12-17  3037  	if (!static_branch_unlikely(&net_high_order_alloc_disable_key)) {
d0164adc89f6bb3 Mel Gorman   2015-11-06  3038  		/* Avoid direct reclaim but allow kswapd to wake */
d0164adc89f6bb3 Mel Gorman   2015-11-06  3039  		pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
d0164adc89f6bb3 Mel Gorman   2015-11-06  3040  					  __GFP_COMP | __GFP_NOWARN |
d0164adc89f6bb3 Mel Gorman   2015-11-06  3041  					  __GFP_NORETRY,
d9b2938aabf757d Eric Dumazet 2014-08-27  3042  					  SKB_FRAG_PAGE_ORDER);
d9b2938aabf757d Eric Dumazet 2014-08-27  3043  		if (likely(pfrag->page)) {
d9b2938aabf757d Eric Dumazet 2014-08-27 @3044  			pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
d9b2938aabf757d Eric Dumazet 2014-08-27  3045  			return true;
d9b2938aabf757d Eric Dumazet 2014-08-27  3046  		}
d9b2938aabf757d Eric Dumazet 2014-08-27  3047  	}
d9b2938aabf757d Eric Dumazet 2014-08-27  3048  	pfrag->page = alloc_page(gfp);
d9b2938aabf757d Eric Dumazet 2014-08-27  3049  	if (likely(pfrag->page)) {
d9b2938aabf757d Eric Dumazet 2014-08-27  3050  		pfrag->size = PAGE_SIZE;
5640f7685831e08 Eric Dumazet 2012-09-23  3051  		return true;
5640f7685831e08 Eric Dumazet 2012-09-23  3052  	}
400dfd3ae899849 Eric Dumazet 2013-10-17  3053  	return false;
400dfd3ae899849 Eric Dumazet 2013-10-17  3054  }
400dfd3ae899849 Eric Dumazet 2013-10-17  3055  EXPORT_SYMBOL(skb_page_frag_refill);
400dfd3ae899849 Eric Dumazet 2013-10-17  3056  

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