Re: [PATCH v3 07/22] mm/mshare: Add mmap support

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

Hi Anthony,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on tip/sched/core trace/for-next tip/x86/core tip/x86/mm kees/for-next/execve linus/master v6.17-rc2 next-20250820]
[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/Anthony-Yznaga/mm-Add-msharefs-filesystem/20250820-091021
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250820010415.699353-8-anthony.yznaga%40oracle.com
patch subject: [PATCH v3 07/22] mm/mshare: Add mmap support
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250821/202508210230.0Zc3YDIy-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250821/202508210230.0Zc3YDIy-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/202508210230.0Zc3YDIy-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/mshare.c:121:16: warning: variable 'mshare_start' set but not used [-Wunused-but-set-variable]
     121 |         unsigned long mshare_start, mshare_size;
         |                       ^
   1 warning generated.


vim +/mshare_start +121 mm/mshare.c

   113	
   114	static unsigned long
   115	msharefs_get_unmapped_area(struct file *file, unsigned long addr,
   116			unsigned long len, unsigned long pgoff, unsigned long flags)
   117	{
   118		struct mshare_data *m_data = file->private_data;
   119		struct mm_struct *mm = current->mm;
   120		struct vm_area_struct *vma, *prev;
 > 121		unsigned long mshare_start, mshare_size;
   122		const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
   123	
   124		mmap_assert_write_locked(mm);
   125	
   126		if ((flags & MAP_TYPE) == MAP_PRIVATE)
   127			return -EINVAL;
   128	
   129		if (!mshare_is_initialized(m_data))
   130			return -EINVAL;
   131	
   132		mshare_start = m_data->start;
   133		mshare_size = m_data->size;
   134	
   135		if (len != mshare_size)
   136			return -EINVAL;
   137	
   138		if (len > mmap_end - mmap_min_addr)
   139			return -ENOMEM;
   140	
   141		if (flags & MAP_FIXED) {
   142			if (!IS_ALIGNED(addr, mshare_align))
   143				return -EINVAL;
   144			return addr;
   145		}
   146	
   147		if (addr) {
   148			addr = ALIGN(addr, mshare_align);
   149			vma = find_vma_prev(mm, addr, &prev);
   150			if (mmap_end - len >= addr && addr >= mmap_min_addr &&
   151			    (!vma || addr + len <= vm_start_gap(vma)) &&
   152			    (!prev || addr >= vm_end_gap(prev)))
   153				return addr;
   154		}
   155	
   156		if (!mm_flags_test(MMF_TOPDOWN, mm))
   157			return msharefs_get_unmapped_area_bottomup(file, addr, len,
   158					pgoff, flags);
   159		else
   160			return msharefs_get_unmapped_area_topdown(file, addr, len,
   161					pgoff, flags);
   162	}
   163	

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