Re: [PATCH] ALSA: core/seq: Optimize the return logic in cc_ev_to_ump_midi2

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

Hi songxiebing,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tiwai-sound/for-next]
[also build test WARNING on tiwai-sound/for-linus linus/master v7.0-rc5 next-20260323]
[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/songxiebing/ALSA-core-seq-Optimize-the-return-logic-in-cc_ev_to_ump_midi2/20260324-013342
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git for-next
patch link:    https://lore.kernel.org/r/20260323024742.220707-1-songxiebing%40kylinos.cn
patch subject: [PATCH] ALSA: core/seq: Optimize the return logic in cc_ev_to_ump_midi2
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20260324/202603240812.jjlE0H3s-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260324/202603240812.jjlE0H3s-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/202603240812.jjlE0H3s-lkp@intel.com/

All warnings (new ones prefixed by >>):

   sound/core/seq/seq_ump_convert.c: In function 'cc_ev_to_ump_midi2':
>> sound/core/seq/seq_ump_convert.c:880:21: warning: this statement may fall through [-Wimplicit-fallthrough=]
     880 |                 ret = 0; // skip
         |                 ~~~~^~~
   sound/core/seq/seq_ump_convert.c:881:9: note: here
     881 |         case UMP_CC_BANK_SELECT_LSB:
         |         ^~~~
   sound/core/seq/seq_ump_convert.c:884:21: warning: this statement may fall through [-Wimplicit-fallthrough=]
     884 |                 ret = 0; // skip
         |                 ~~~~^~~
   sound/core/seq/seq_ump_convert.c:885:9: note: here
     885 |         case UMP_CC_DATA_LSB:
         |         ^~~~


vim +880 sound/core/seq/seq_ump_convert.c

   833	
   834	/* convert CC event to MIDI 2.0 UMP */
   835	static int cc_ev_to_ump_midi2(const struct snd_seq_event *event,
   836				      struct snd_seq_client_port *dest_port,
   837				      union snd_ump_midi2_msg *data,
   838				      unsigned char status)
   839	{
   840		unsigned char channel = event->data.control.channel & 0x0f;
   841		unsigned char index = event->data.control.param & 0x7f;
   842		unsigned char val = event->data.control.value & 0x7f;
   843		struct ump_cvt_to_ump_bank *cc = &dest_port->midi2_bank[channel];
   844		int ret = 0;
   845	
   846		/* process special CC's (bank/rpn/nrpn) */
   847		switch (index) {
   848		case UMP_CC_RPN_MSB:
   849			ret = fill_rpn(cc, data, channel, true);
   850			cc->rpn_set = 1;
   851			cc->cc_rpn_msb = val;
   852			if (cc->cc_rpn_msb == 0x7f && cc->cc_rpn_lsb == 0x7f)
   853				reset_rpn(cc);
   854			break;
   855		case UMP_CC_RPN_LSB:
   856			ret = fill_rpn(cc, data, channel, true);
   857			cc->rpn_set = 1;
   858			cc->cc_rpn_lsb = val;
   859			if (cc->cc_rpn_msb == 0x7f && cc->cc_rpn_lsb == 0x7f)
   860				reset_rpn(cc);
   861			break;
   862		case UMP_CC_NRPN_MSB:
   863			ret = fill_rpn(cc, data, channel, true);
   864			cc->nrpn_set = 1;
   865			cc->cc_nrpn_msb = val;
   866			break;
   867		case UMP_CC_NRPN_LSB:
   868			ret = fill_rpn(cc, data, channel, true);
   869			cc->nrpn_set = 1;
   870			cc->cc_nrpn_lsb = val;
   871			break;
   872		case UMP_CC_DATA:
   873			cc->cc_data_msb_set = 1;
   874			cc->cc_data_msb = val;
   875			ret = fill_rpn(cc, data, channel, false);
   876			break;
   877		case UMP_CC_BANK_SELECT:
   878			cc->bank_set = 1;
   879			cc->cc_bank_msb = val;
 > 880			ret = 0; // skip
   881		case UMP_CC_BANK_SELECT_LSB:
   882			cc->bank_set = 1;
   883			cc->cc_bank_lsb = val;
   884			ret = 0; // skip
   885		case UMP_CC_DATA_LSB:
   886			cc->cc_data_lsb_set = 1;
   887			cc->cc_data_lsb = val;
   888			ret = fill_rpn(cc, data, channel, false);
   889			break;
   890		default:
   891			data->cc.status = status;
   892			data->cc.channel = channel;
   893			data->cc.index = index;
   894			data->cc.data = upscale_7_to_32bit(event->data.control.value & 0x7f);
   895			ret = 1;
   896			break;
   897		}
   898	
   899		return ret;
   900	}
   901	

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