Re: [PATCH v2] nfs: protect nfs41_impl_id by rcu

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

Hi Li,

kernel test robot noticed the following build errors:

[auto build test ERROR on trondmy-nfs/linux-next]
[also build test ERROR on linus/master v6.11-rc5 next-20240830]
[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/Li-Lingfeng/nfs-protect-nfs41_impl_id-by-rcu/20240829-213622
base:   git://git.linux-nfs.org/projects/trondmy/linux-nfs.git linux-next
patch link:    https://lore.kernel.org/r/20240829133743.1008788-1-lilingfeng3%40huawei.com
patch subject: [PATCH v2] nfs: protect nfs41_impl_id by rcu
config: i386-randconfig-001-20240830 (https://download.01.org/0day-ci/archive/20240830/202408302315.02P7HuVM-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240830/202408302315.02P7HuVM-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/202408302315.02P7HuVM-lkp@intel.com/

All errors (new ones prefixed by >>):

>> fs/nfs/nfs4client.c:286:34: error: incomplete definition of type 'struct nfs41_impl_id'
     286 |         struct nfs41_impl_id *impl_id = container_of(head, struct nfs41_impl_id, __rcu_head);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/container_of.h:20:47: note: expanded from macro 'container_of'
      20 |         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
      21 |                       __same_type(*(ptr), void),                        \
         |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      22 |                       "pointer type mismatch in container_of()");       \
         |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler_types.h:451:74: note: expanded from macro '__same_type'
     451 | #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
         |                                                                          ^
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
      77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
         |                                  ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   include/linux/nfs_fs_sb.h:23:8: note: forward declaration of 'struct nfs41_impl_id'
      23 | struct nfs41_impl_id;
         |        ^
>> fs/nfs/nfs4client.c:286:34: error: offsetof of incomplete type 'struct nfs41_impl_id'
     286 |         struct nfs41_impl_id *impl_id = container_of(head, struct nfs41_impl_id, __rcu_head);
         |                                         ^                  ~~~~~~
   include/linux/container_of.h:23:21: note: expanded from macro 'container_of'
      23 |         ((type *)(__mptr - offsetof(type, member))); })
         |                            ^        ~~~~
   include/linux/stddef.h:16:32: note: expanded from macro 'offsetof'
      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
         |                                 ^                  ~~~~
   include/linux/nfs_fs_sb.h:23:8: note: forward declaration of 'struct nfs41_impl_id'
      23 | struct nfs41_impl_id;
         |        ^
>> fs/nfs/nfs4client.c:286:24: error: initializing 'struct nfs41_impl_id *' with an expression of incompatible type 'void'
     286 |         struct nfs41_impl_id *impl_id = container_of(head, struct nfs41_impl_id, __rcu_head);
         |                               ^         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   fs/nfs/nfs4client.c:304:27: error: incomplete definition of type 'struct nfs41_impl_id'
     304 |                 call_rcu(&clp->cl_implid->__rcu_head, nfs4_free_impl_id_rcu);
         |                           ~~~~~~~~~~~~~~^
   include/linux/nfs_fs_sb.h:23:8: note: forward declaration of 'struct nfs41_impl_id'
      23 | struct nfs41_impl_id;
         |        ^
   4 errors generated.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for FB_IOMEM_HELPERS
   Depends on [n]: HAS_IOMEM [=y] && FB_CORE [=n]
   Selected by [m]:
   - DRM_XE_DISPLAY [=y] && HAS_IOMEM [=y] && DRM [=y] && DRM_XE [=m] && DRM_XE [=m]=m [=m]


vim +286 fs/nfs/nfs4client.c

   283	
   284	static void nfs4_free_impl_id_rcu(struct rcu_head *head)
   285	{
 > 286		struct nfs41_impl_id *impl_id = container_of(head, struct nfs41_impl_id, __rcu_head);
   287	
   288		kfree(impl_id);
   289	}
   290	

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