Re: [PATCH 3/4] mm: shmem: add large folio support for tmpfs

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

Hi Baolin,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on next-20241108]
[cannot apply to linus/master v6.12-rc6]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Baolin-Wang/mm-factor-out-the-order-calculation-into-a-new-helper/20241108-121545
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/e2f4e483f75e54be0654fafb2147822faacac16d.1731038280.git.baolin.wang%40linux.alibaba.com
patch subject: [PATCH 3/4] mm: shmem: add large folio support for tmpfs
config: x86_64-rhel-8.3 (https://download.01.org/0day-ci/archive/20241108/202411081926.LQ3wEK7l-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241108/202411081926.LQ3wEK7l-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/202411081926.LQ3wEK7l-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/shmem.c:567: warning: Function parameter or struct member 'write_end' not described in 'shmem_mapping_size_orders'
>> mm/shmem.c:567: warning: Excess function parameter 'size' description in 'shmem_mapping_size_orders'


vim +567 mm/shmem.c

   551	
   552	/**
   553	 * shmem_mapping_size_orders - Get allowable folio orders for the given file size.
   554	 * @mapping: Target address_space.
   555	 * @index: The page index.
   556	 * @size: The suggested size of the folio to create.
   557	 *
   558	 * This returns a high order for folios (when supported) based on the file size
   559	 * which the mapping currently allows at the given index. The index is relevant
   560	 * due to alignment considerations the mapping might have. The returned order
   561	 * may be less than the size passed.
   562	 *
   563	 * Return: The orders.
   564	 */
   565	static inline unsigned int
   566	shmem_mapping_size_orders(struct address_space *mapping, pgoff_t index, loff_t write_end)
 > 567	{
   568		unsigned int order;
   569		size_t size;
   570	
   571		if (!mapping_large_folio_support(mapping) || !write_end)
   572			return 0;
   573	
   574		/* Calculate the write size based on the write_end */
   575		size = write_end - (index << PAGE_SHIFT);
   576		order = filemap_get_order(size);
   577		if (!order)
   578			return 0;
   579	
   580		/* If we're not aligned, allocate a smaller folio */
   581		if (index & ((1UL << order) - 1))
   582			order = __ffs(index);
   583	
   584		order = min_t(size_t, order, MAX_PAGECACHE_ORDER);
   585		return order > 0 ? BIT(order + 1) - 1 : 0;
   586	}
   587	

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