[linyunsheng:page_frag_cache_v5 14/14] mm/page_frag_cache.c:291 __page_frag_alloc_va_align() error: uninitialized symbol 'remaining'.

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

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Yunsheng Lin <linyunsheng@huawei.com>

tree:   https://github.com/gestionlin/linux.git page_frag_cache_v5
head:   e6543161a8d13e28e244803a755a007021b9dea7
commit: e6543161a8d13e28e244803a755a007021b9dea7 [14/14] add alloc_pg api and refactor alloc_va api
:::::: branch date: 6 hours ago
:::::: commit date: 6 hours ago
config: i386-randconfig-141-20240518 (https://download.01.org/0day-ci/archive/20240519/202405190246.CAWMWHpE-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)

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>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202405190246.CAWMWHpE-lkp@intel.com/

smatch warnings:
mm/page_frag_cache.c:291 __page_frag_alloc_va_align() error: uninitialized symbol 'remaining'.

vim +/remaining +291 mm/page_frag_cache.c

8b045aa063651c Yunsheng Lin 2024-05-15  269  
616ae9b1b510e1 Yunsheng Lin 2024-05-15  270  /**
616ae9b1b510e1 Yunsheng Lin 2024-05-15  271   * __page_frag_alloc_va_align() - Alloc a page fragment with aligning
616ae9b1b510e1 Yunsheng Lin 2024-05-15  272   * requirement.
616ae9b1b510e1 Yunsheng Lin 2024-05-15  273   * @nc: page_frag cache from which to allocate
616ae9b1b510e1 Yunsheng Lin 2024-05-15  274   * @fragsz: the requested fragment size
616ae9b1b510e1 Yunsheng Lin 2024-05-15  275   * @gfp_mask: the allocation gfp to use when cache need to be refilled
616ae9b1b510e1 Yunsheng Lin 2024-05-15  276   * @align_mask: the requested aligning requirement for the 'va'
616ae9b1b510e1 Yunsheng Lin 2024-05-15  277   *
616ae9b1b510e1 Yunsheng Lin 2024-05-15  278   * Get a page fragment from page_frag cache with aligning requirement.
616ae9b1b510e1 Yunsheng Lin 2024-05-15  279   *
616ae9b1b510e1 Yunsheng Lin 2024-05-15  280   * Return:
616ae9b1b510e1 Yunsheng Lin 2024-05-15  281   * Return va of the page fragment, otherwise return NULL.
616ae9b1b510e1 Yunsheng Lin 2024-05-15  282   */
3ba205fc955f3f Yunsheng Lin 2024-05-15  283  void *__page_frag_alloc_va_align(struct page_frag_cache *nc,
8b045aa063651c Yunsheng Lin 2024-05-15  284  				 unsigned int fragsz, gfp_t gfp_mask,
8b045aa063651c Yunsheng Lin 2024-05-15  285  				 unsigned int align_mask)
8b045aa063651c Yunsheng Lin 2024-05-15  286  {
96b2e1c760d339 Yunsheng Lin 2024-05-15  287  	struct encoded_va *encoded_va;
96b2e1c760d339 Yunsheng Lin 2024-05-15  288  	unsigned int remaining;
8b045aa063651c Yunsheng Lin 2024-05-15  289  	struct page *page;
8b045aa063651c Yunsheng Lin 2024-05-15  290  
e6543161a8d13e Yunsheng Lin 2024-05-18 @291  	if (unlikely(fragsz > remaining)) {
96b2e1c760d339 Yunsheng Lin 2024-05-15  292  		/* fragsz is not supposed to be bigger than PAGE_SIZE as we are
96b2e1c760d339 Yunsheng Lin 2024-05-15  293  		 * allowing order 3 page allocation to fail easily under low
96b2e1c760d339 Yunsheng Lin 2024-05-15  294  		 * memory condition.
96b2e1c760d339 Yunsheng Lin 2024-05-15  295  		 */
e6543161a8d13e Yunsheng Lin 2024-05-18  296  		if (WARN_ON_ONCE(fragsz > PAGE_SIZE) ||
e6543161a8d13e Yunsheng Lin 2024-05-18  297  		    unlikely(!page_frag_cache_refill(nc, gfp_mask)))
96b2e1c760d339 Yunsheng Lin 2024-05-15  298  			return NULL;
8b045aa063651c Yunsheng Lin 2024-05-15  299  	}
8b045aa063651c Yunsheng Lin 2024-05-15  300  
e6543161a8d13e Yunsheng Lin 2024-05-18  301  	encoded_va = nc->encoded_va;
96b2e1c760d339 Yunsheng Lin 2024-05-15  302  	remaining = nc->remaining & align_mask;
96b2e1c760d339 Yunsheng Lin 2024-05-15  303  	nc->remaining = remaining - fragsz;
8b045aa063651c Yunsheng Lin 2024-05-15  304  	nc->pagecnt_bias--;
8b045aa063651c Yunsheng Lin 2024-05-15  305  
96b2e1c760d339 Yunsheng Lin 2024-05-15  306  	return encoded_page_address(encoded_va) +
96b2e1c760d339 Yunsheng Lin 2024-05-15  307  		__page_frag_cache_page_offset(encoded_va, remaining);
8b045aa063651c Yunsheng Lin 2024-05-15  308  }
3ba205fc955f3f Yunsheng Lin 2024-05-15  309  EXPORT_SYMBOL(__page_frag_alloc_va_align);
8b045aa063651c Yunsheng Lin 2024-05-15  310  

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