Re: [PATCH] tracing: Move snapshot code out of trace.c and into trace_snapshot.c

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

Hi Steven,

kernel test robot noticed the following build warnings:

[auto build test WARNING on v7.0-rc2]
[cannot apply to trace/for-next linus/master next-20260305]
[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/Steven-Rostedt/tracing-Move-snapshot-code-out-of-trace-c-and-into-trace_snapshot-c/20260306-102714
base:   v7.0-rc2
patch link:    https://lore.kernel.org/r/20260305211810.3f48aa07%40robin
patch subject: [PATCH] tracing: Move snapshot code out of trace.c and into trace_snapshot.c
config: sh-defconfig (https://download.01.org/0day-ci/archive/20260307/202603070253.0Z0n4vtm-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260307/202603070253.0Z0n4vtm-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/202603070253.0Z0n4vtm-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/trace/trace.c:820:5: warning: no previous prototype for 'tracing_alloc_snapshot' [-Wmissing-prototypes]
     820 | int tracing_alloc_snapshot(void)
         |     ^~~~~~~~~~~~~~~~~~~~~~


vim +/tracing_alloc_snapshot +820 kernel/trace/trace.c

ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  792) 
93e31ffbf417a84 Tom Zanussi              2013-10-24  793  /**
93e31ffbf417a84 Tom Zanussi              2013-10-24  794   * tracing_alloc_snapshot - allocate snapshot buffer.
93e31ffbf417a84 Tom Zanussi              2013-10-24  795   *
93e31ffbf417a84 Tom Zanussi              2013-10-24  796   * This only allocates the snapshot buffer if it isn't already
93e31ffbf417a84 Tom Zanussi              2013-10-24  797   * allocated - it doesn't also take a snapshot.
93e31ffbf417a84 Tom Zanussi              2013-10-24  798   *
93e31ffbf417a84 Tom Zanussi              2013-10-24  799   * This is meant to be used in cases where the snapshot buffer needs
93e31ffbf417a84 Tom Zanussi              2013-10-24  800   * to be set up for events that can't sleep but need to be able to
93e31ffbf417a84 Tom Zanussi              2013-10-24  801   * trigger a snapshot.
93e31ffbf417a84 Tom Zanussi              2013-10-24  802   */
93e31ffbf417a84 Tom Zanussi              2013-10-24  803  int tracing_alloc_snapshot(void)
93e31ffbf417a84 Tom Zanussi              2013-10-24  804  {
93e31ffbf417a84 Tom Zanussi              2013-10-24  805  	struct trace_array *tr = &global_trace;
93e31ffbf417a84 Tom Zanussi              2013-10-24  806  	int ret;
93e31ffbf417a84 Tom Zanussi              2013-10-24  807  
2824f5033248600 Steven Rostedt (VMware   2018-05-28  808) 	ret = tracing_alloc_snapshot_instance(tr);
93e31ffbf417a84 Tom Zanussi              2013-10-24  809  	WARN_ON(ret < 0);
93e31ffbf417a84 Tom Zanussi              2013-10-24  810  
93e31ffbf417a84 Tom Zanussi              2013-10-24  811  	return ret;
93e31ffbf417a84 Tom Zanussi              2013-10-24  812  }
93e31ffbf417a84 Tom Zanussi              2013-10-24  813  EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  814) #else
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  815) void tracing_snapshot(void)
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  816) {
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  817) 	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  818) }
1b22e382ab40b0e Steven Rostedt (Red Hat  2013-03-09  819) EXPORT_SYMBOL_GPL(tracing_snapshot);
93e31ffbf417a84 Tom Zanussi              2013-10-24 @820  int tracing_alloc_snapshot(void)
93e31ffbf417a84 Tom Zanussi              2013-10-24  821  {
93e31ffbf417a84 Tom Zanussi              2013-10-24  822  	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
93e31ffbf417a84 Tom Zanussi              2013-10-24  823  	return -ENODEV;
93e31ffbf417a84 Tom Zanussi              2013-10-24  824  }
93e31ffbf417a84 Tom Zanussi              2013-10-24  825  EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  826) void tracing_snapshot_alloc(void)
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  827) {
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  828) 	/* Give warning */
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  829) 	tracing_snapshot();
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  830) }
1b22e382ab40b0e Steven Rostedt (Red Hat  2013-03-09  831) EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  832) #endif /* CONFIG_TRACER_SNAPSHOT */
ad909e21bbe69f1 Steven Rostedt (Red Hat  2013-03-06  833) 

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