Hi Gao,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc4 next-20190816]
[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/Gao-Xiang/staging-erofs-fix-an-error-handling-in-erofs_readdir/20190818-191344
config: sparc64-allmodconfig (attached as .config)
compiler: sparc64-linux-gcc (GCC) 7.4.0
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=7.4.0 make.cross ARCH=sparc64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/staging//erofs/dir.c: In function 'erofs_readdir':
>> drivers/staging//erofs/dir.c:110:11: error: 'EFSCORRUPTED' undeclared (first use in this function)
       err = -EFSCORRUPTED;
              ^~~~~~~~~~~~
   drivers/staging//erofs/dir.c:110:11: note: each undeclared identifier is reported only once for each function it appears in

vim +/EFSCORRUPTED +110 drivers/staging//erofs/dir.c

    85	
    86	static int erofs_readdir(struct file *f, struct dir_context *ctx)
    87	{
    88		struct inode *dir = file_inode(f);
    89		struct address_space *mapping = dir->i_mapping;
    90		const size_t dirsize = i_size_read(dir);
    91		unsigned int i = ctx->pos / EROFS_BLKSIZ;
    92		unsigned int ofs = ctx->pos % EROFS_BLKSIZ;
    93		int err = 0;
    94		bool initial = true;
    95	
    96		while (ctx->pos < dirsize) {
    97			struct page *dentry_page;
    98			struct erofs_dirent *de;
    99			unsigned int nameoff, maxsize;
   100	
   101			dentry_page = read_mapping_page(mapping, i, NULL);
   102			if (dentry_page == ERR_PTR(-ENOMEM)) {
   103				errln("no memory to readdir of logical block %u of nid %llu",
   104				      i, EROFS_V(dir)->nid);
   105				err = -ENOMEM;
   106				break;
   107			} else if (IS_ERR(dentry_page)) {
   108				errln("fail to readdir of logical block %u of nid %llu",
   109				      i, EROFS_V(dir)->nid);
 > 110				err = -EFSCORRUPTED;
   111				break;
   112			}
   113	
   114			de = (struct erofs_dirent *)kmap(dentry_page);
   115	
   116			nameoff = le16_to_cpu(de->nameoff);
   117	
   118			if (unlikely(nameoff < sizeof(struct erofs_dirent) ||
   119				     nameoff >= PAGE_SIZE)) {
   120				errln("%s, invalid de[0].nameoff %u",
   121				      __func__, nameoff);
   122	
   123				err = -EIO;
   124				goto skip_this;
   125			}
   126	
   127			maxsize = min_t(unsigned int,
   128					dirsize - ctx->pos + ofs, PAGE_SIZE);
   129	
   130			/* search dirents at the arbitrary position */
   131			if (unlikely(initial)) {
   132				initial = false;
   133	
   134				ofs = roundup(ofs, sizeof(struct erofs_dirent));
   135				if (unlikely(ofs >= nameoff))
   136					goto skip_this;
   137			}
   138	
   139			err = erofs_fill_dentries(ctx, de, &ofs, nameoff, maxsize);
   140	skip_this:
   141			kunmap(dentry_page);
   142	
   143			put_page(dentry_page);
   144	
   145			ctx->pos = blknr_to_addr(i) + ofs;
   146	
   147			if (unlikely(err))
   148				break;
   149			++i;
   150			ofs = 0;
   151		}
   152		return err < 0 ? err : 0;
   153	}
   154	

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