Re: [PATCH 1/7] Revert "mm: take i_mmap_lock in unmap_mapping_range() for DAX"

[kbuild test robot <lkp@xxxxxxxxx>]

Hi Dave,

[auto build test results on v4.3-rc3 -- if it's inappropriate base, please 
ignore]

reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

>> fs/dax.c:626:50: sparse: incorrect type in argument 1 (different address 
>> spaces)
   fs/dax.c:626:50:    expected void *page
   fs/dax.c:626:50:    got void [noderef] <asn:5>*

vim +626 fs/dax.c

   610                  result = VM_FAULT_NOPAGE;
   611                  spin_unlock(ptl);
   612          } else {
   613                  sector = bh.b_blocknr << (blkbits - 9);
   614                  length = bdev_direct_access(bh.b_bdev, sector, &kaddr, 
&pfn,
   615                                                  bh.b_size);
   616                  if (length < 0) {
   617                          result = VM_FAULT_SIGBUS;
   618                          goto out;
   619                  }
   620                  if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
   621                          goto fallback;
   622  
   623                  if (buffer_unwritten(&bh) || buffer_new(&bh)) {
   624                          int i;
   625                          for (i = 0; i < PTRS_PER_PMD; i++)
 > 626                                  clear_page(kaddr + i * PAGE_SIZE);
   627                          count_vm_event(PGMAJFAULT);
   628                          mem_cgroup_count_vm_event(vma->vm_mm, 
PGMAJFAULT);
   629                          result |= VM_FAULT_MAJOR;
   630                  }
   631  
   632                  result |= vmf_insert_pfn_pmd(vma, address, pmd, pfn, 
write);
   633          }
   634  

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