Re: [PATCH 1/3] Change inode_operations.mkdir to return struct dentry *

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

Hi NeilBrown,

kernel test robot noticed the following build errors:

[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on trondmy-nfs/linux-next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus cifs/for-next xfs-linux/for-next linus/master v6.14-rc2 next-20250214]
[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/NeilBrown/nfs-change-mkdir-inode_operation-to-return-alternate-dentry-if-needed/20250214-141741
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link:    https://lore.kernel.org/r/20250214052204.3105610-2-neilb%40suse.de
patch subject: [PATCH 1/3] Change inode_operations.mkdir to return struct dentry *
config: um-randconfig-001-20250215 (https://download.01.org/0day-ci/archive/20250215/202502151519.0MA7hz8D-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 910be4ff90d7d07bd4518ea03b85c0974672bf9c)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250215/202502151519.0MA7hz8D-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/202502151519.0MA7hz8D-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from fs/hostfs/hostfs_kern.c:13:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:549:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     549 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:567:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     567 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from fs/hostfs/hostfs_kern.c:13:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:585:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from fs/hostfs/hostfs_kern.c:13:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:12:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:5:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:14:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:601:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     601 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:616:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     616 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:631:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     631 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:724:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     724 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:737:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     737 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:750:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     750 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:764:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     764 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:778:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     778 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:792:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     792 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
>> fs/hostfs/hostfs_kern.c:689:10: error: incompatible integer to pointer conversion returning 'int' from a function with result type 'struct dentry *' [-Wint-conversion]
     689 |                 return -ENOMEM;
         |                        ^~~~~~~
   12 warnings and 1 error generated.


vim +689 fs/hostfs/hostfs_kern.c

^1da177e4c3f41 Linus Torvalds    2005-04-16  681  
456289e0bd14ce NeilBrown         2025-02-14  682  static struct dentry *hostfs_mkdir(struct mnt_idmap *idmap, struct inode *ino,
549c7297717c32 Christian Brauner 2021-01-21  683  				   struct dentry *dentry, umode_t mode)
^1da177e4c3f41 Linus Torvalds    2005-04-16  684  {
^1da177e4c3f41 Linus Torvalds    2005-04-16  685  	char *file;
^1da177e4c3f41 Linus Torvalds    2005-04-16  686  	int err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  687  
c5322220eb91b9 Al Viro           2010-06-06  688  	if ((file = dentry_name(dentry)) == NULL)
f1adc05e773830 Jeff Dike         2007-05-08 @689  		return -ENOMEM;
^1da177e4c3f41 Linus Torvalds    2005-04-16  690  	err = do_mkdir(file, mode);
e9193059b1b373 Al Viro           2010-06-06  691  	__putname(file);
456289e0bd14ce NeilBrown         2025-02-14  692  	if (err)
456289e0bd14ce NeilBrown         2025-02-14  693  		return ERR_PTR(err);
456289e0bd14ce NeilBrown         2025-02-14  694  	else
456289e0bd14ce NeilBrown         2025-02-14  695  		return dentry;
^1da177e4c3f41 Linus Torvalds    2005-04-16  696  }
^1da177e4c3f41 Linus Torvalds    2005-04-16  697  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki