ALSA: core/seq: Optimize the return logic in cc_ev_to_ump_midi2

There are multiple early return branches within the func, and compiler
optimizations(such as -O2/-O3)lead to abnormal stack frame analysis -
objtool cannot comfirm that the stack frames of all branches can be
correctly restored, thus generating false warnings.

Below:
>> sound/core/seq/seq_ump_convert.o: warning: objtool: cc_ev_to_ump_midi2+0x589: return with modified stack frame

So we modify it by uniformly returning at the and of the function.

Signed-off-by: songxiebing <songxiebing@kylinos.cn>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202503200535.J3hAvcjw-lkp@intel.com/
Link: https://patch.msgid.link/20260325015119.175835-1-songxiebing@kylinos.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/seq/seq_ump_convert.c b/sound/core/seq/seq_ump_convert.c
index db2f169cae11ea99bdec2325bc2b427f405f313c..ff4ee26adad1fc4ea9a092f4ec9c786450f52b02 100644 (file)
--- a/sound/core/seq/seq_ump_convert.c
+++ b/sound/core/seq/seq_ump_convert.c
@@ -841,7 +841,7 @@ static int cc_ev_to_ump_midi2(const struct snd_seq_event *event,
        unsigned char index = event->data.control.param & 0x7f;
        unsigned char val = event->data.control.value & 0x7f;
        struct ump_cvt_to_ump_bank *cc = &dest_port->midi2_bank[channel];
-       int ret;
+       int ret = 0;
 
        /* process special CC's (bank/rpn/nrpn) */
        switch (index) {
@@ -851,47 +851,54 @@ static int cc_ev_to_ump_midi2(const struct snd_seq_event *event,
                cc->cc_rpn_msb = val;
                if (cc->cc_rpn_msb == 0x7f && cc->cc_rpn_lsb == 0x7f)
                        reset_rpn(cc);
-               return ret;
+               break;
        case UMP_CC_RPN_LSB:
                ret = fill_rpn(cc, data, channel, true);
                cc->rpn_set = 1;
                cc->cc_rpn_lsb = val;
                if (cc->cc_rpn_msb == 0x7f && cc->cc_rpn_lsb == 0x7f)
                        reset_rpn(cc);
-               return ret;
+               break;
        case UMP_CC_NRPN_MSB:
                ret = fill_rpn(cc, data, channel, true);
                cc->nrpn_set = 1;
                cc->cc_nrpn_msb = val;
-               return ret;
+               break;
        case UMP_CC_NRPN_LSB:
                ret = fill_rpn(cc, data, channel, true);
                cc->nrpn_set = 1;
                cc->cc_nrpn_lsb = val;
-               return ret;
+               break;
        case UMP_CC_DATA:
                cc->cc_data_msb_set = 1;
                cc->cc_data_msb = val;
-               return fill_rpn(cc, data, channel, false);
+               ret = fill_rpn(cc, data, channel, false);
+               break;
        case UMP_CC_BANK_SELECT:
                cc->bank_set = 1;
                cc->cc_bank_msb = val;
-               return 0; // skip
+               ret = 0; // skip
+               break;
        case UMP_CC_BANK_SELECT_LSB:
                cc->bank_set = 1;
                cc->cc_bank_lsb = val;
-               return 0; // skip
+               ret = 0; // skip
+               break;
        case UMP_CC_DATA_LSB:
                cc->cc_data_lsb_set = 1;
                cc->cc_data_lsb = val;
-               return fill_rpn(cc, data, channel, false);
+               ret = fill_rpn(cc, data, channel, false);
+               break;
+       default:
+               data->cc.status = status;
+               data->cc.channel = channel;
+               data->cc.index = index;
+               data->cc.data = upscale_7_to_32bit(event->data.control.value & 0x7f);
+               ret = 1;
+               break;
        }
 
-       data->cc.status = status;
-       data->cc.channel = channel;
-       data->cc.index = index;
-       data->cc.data = upscale_7_to_32bit(event->data.control.value & 0x7f);
-       return 1;
+       return ret;
 }
 
 /* convert one-parameter control event to MIDI 2.0 UMP */