Hi Vivek,

I love your patch! Perhaps something to improve:

[auto build test WARNING on fuse/for-next]
[also build test WARNING on v4.20-rc6]
[cannot apply to next-20181211]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Vivek-Goyal/virtio-fs-shared-file-system-for-virtual-machines/20181211-103034
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git for-next
config: arm64-allmodconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=arm64 

All warnings (new ones prefixed by >>):

   fs/ext2/inode.c: In function 'ext2_dax_writepages':
   fs/ext2/inode.c:959:33: error: passing argument 3 of 'dax_writeback_mapping_range' from incompatible pointer type [-Werror=incompatible-pointer-types]
       mapping->host->i_sb->s_bdev, wbc);
                                    ^~~
   In file included from fs/ext2/inode.c:29:0:
   include/linux/dax.h:87:5: note: expected 'struct dax_device *' but argument is of type 'struct writeback_control *'
    int dax_writeback_mapping_range(struct address_space *mapping,
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/ext2/inode.c:958:9: error: too few arguments to function 'dax_writeback_mapping_range'
     return dax_writeback_mapping_range(mapping,
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from fs/ext2/inode.c:29:0:
   include/linux/dax.h:87:5: note: declared here
    int dax_writeback_mapping_range(struct address_space *mapping,
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>> fs/ext2/inode.c:960:1: warning: control reaches end of non-void function [-Wreturn-type]
    }
    ^
   cc1: some warnings being treated as errors

vim +960 fs/ext2/inode.c

7f6d5b52 Ross Zwisler   2016-02-26  954  
fb094c90 Dan Williams   2017-12-21  955  static int
fb094c90 Dan Williams   2017-12-21  956  ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
fb094c90 Dan Williams   2017-12-21  957  {
fb094c90 Dan Williams   2017-12-21 @958  	return dax_writeback_mapping_range(mapping,
fb094c90 Dan Williams   2017-12-21  959  			mapping->host->i_sb->s_bdev, wbc);
^1da177e Linus Torvalds 2005-04-16 @960  }
^1da177e Linus Torvalds 2005-04-16  961  

:::::: The code at line 960 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

:::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
:::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>

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