Re: [PATCH v2] drivers: nvme: target: core: Pass lockdep expression to RCU lists

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

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Hi Amol,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on hch-configfs/for-next]
[also build test WARNING on linux/master linus/master v5.5-rc5 next-20200110]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Amol-Grover/drivers-nvme-target-core-Pass-lockdep-expression-to-RCU-lists/20200111-084508
base:   git://git.infradead.org/users/hch/configfs.git for-next
config: sh-allmodconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 7.5.0
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=7.5.0 make.cross ARCH=sh 

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

All warnings (new ones prefixed by >>):

   In file included from include/linux/rbtree.h:22:0,
                    from include/linux/mm_types.h:10,
                    from include/linux/mmzone.h:21,
                    from include/linux/gfp.h:6,
                    from include/linux/umh.h:4,
                    from include/linux/kmod.h:9,
                    from include/linux/module.h:13,
                    from drivers/nvme/target/core.c:7:
   drivers/nvme/target/core.c: In function 'nvmet_setup_p2p_ns_map':
   drivers/nvme/target/core.c:1179:22: error: 'subsys' undeclared (first use in this function); did you mean 'to_subsys'?
        lockdep_is_held(&subsys->lock))
                         ^
   include/linux/rcupdate.h:263:52: note: in definition of macro 'RCU_LOCKDEP_WARN'
      if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \
                                                       ^
   include/linux/rculist.h:371:7: note: in expansion of macro '__list_check_rcu'
     for (__list_check_rcu(dummy, ## cond, 0),   \
          ^~~~~~~~~~~~~~~~
>> include/linux/rculist.h:371:34: note: in expansion of macro 'lockdep_is_held'
     for (__list_check_rcu(dummy, ## cond, 0),   \
                                     ^~~~
   drivers/nvme/target/core.c:1178:2: note: in expansion of macro 'list_for_each_entry_rcu'
     list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link,
     ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/nvme/target/core.c:1179:22: note: each undeclared identifier is reported only once for each function it appears in
        lockdep_is_held(&subsys->lock))
                         ^
   include/linux/rcupdate.h:263:52: note: in definition of macro 'RCU_LOCKDEP_WARN'
      if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \
                                                       ^
   include/linux/rculist.h:371:7: note: in expansion of macro '__list_check_rcu'
     for (__list_check_rcu(dummy, ## cond, 0),   \
          ^~~~~~~~~~~~~~~~
>> include/linux/rculist.h:371:34: note: in expansion of macro 'lockdep_is_held'
     for (__list_check_rcu(dummy, ## cond, 0),   \
                                     ^~~~
   drivers/nvme/target/core.c:1178:2: note: in expansion of macro 'list_for_each_entry_rcu'
     list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link,
     ^~~~~~~~~~~~~~~~~~~~~~~

vim +/lockdep_is_held +371 include/linux/rculist.h

ff3c44e6750545 Tom Herbert             2016-03-07  358  
82524746c27fa4 Franck Bui-Huu          2008-05-12  359  /**
82524746c27fa4 Franck Bui-Huu          2008-05-12  360   * list_for_each_entry_rcu	-	iterate over rcu list of given type
82524746c27fa4 Franck Bui-Huu          2008-05-12  361   * @pos:	the type * to use as a loop cursor.
82524746c27fa4 Franck Bui-Huu          2008-05-12  362   * @head:	the head for your list.
3943f42c11896c Andrey Utkin            2014-11-14  363   * @member:	the name of the list_head within the struct.
28875945ba98d1 Joel Fernandes (Google  2019-07-16  364)  * @cond:	optional lockdep expression if called from non-RCU protection.
82524746c27fa4 Franck Bui-Huu          2008-05-12  365   *
82524746c27fa4 Franck Bui-Huu          2008-05-12  366   * This list-traversal primitive may safely run concurrently with
82524746c27fa4 Franck Bui-Huu          2008-05-12  367   * the _rcu list-mutation primitives such as list_add_rcu()
82524746c27fa4 Franck Bui-Huu          2008-05-12  368   * as long as the traversal is guarded by rcu_read_lock().
82524746c27fa4 Franck Bui-Huu          2008-05-12  369   */
28875945ba98d1 Joel Fernandes (Google  2019-07-16  370) #define list_for_each_entry_rcu(pos, head, member, cond...)		\
28875945ba98d1 Joel Fernandes (Google  2019-07-16 @371) 	for (__list_check_rcu(dummy, ## cond, 0),			\
28875945ba98d1 Joel Fernandes (Google  2019-07-16  372) 	     pos = list_entry_rcu((head)->next, typeof(*pos), member);	\
e66eed651fd18a Linus Torvalds          2011-05-19  373  		&pos->member != (head);					\
72c6a9870f9010 Jiri Pirko              2009-04-14  374  		pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
82524746c27fa4 Franck Bui-Huu          2008-05-12  375  

:::::: The code at line 371 was first introduced by commit
:::::: 28875945ba98d1b47a8a706812b6494d165bb0a0 rcu: Add support for consolidated-RCU reader checking

:::::: TO: Joel Fernandes (Google) <joel@joelfernandes.org>
:::::: CC: Paul E. McKenney <paulmck@linux.ibm.com>

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation

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