Re: [bug report] ALSA: ump: Add legacy raw MIDI support

[Takashi Iwai <tiwai@suse.de>]

On Thu, 25 May 2023 09:57:47 +0200,
Dan Carpenter wrote:
> 
> Hello Takashi Iwai,
> 
> The patch 0b5288f5fe63: "ALSA: ump: Add legacy raw MIDI support" from
> May 23, 2023, leads to the following Smatch static checker warning:
> 
> 	sound/core/ump_convert.c:343 cvt_legacy_cmd_to_ump()
> 	warn: duplicate check 'buf[2]' (previous on line 333)
> 
> sound/core/ump_convert.c
>     305 static int cvt_legacy_cmd_to_ump(struct snd_ump_endpoint *ump,
>     306                                  struct ump_cvt_to_ump *cvt,
>     307                                  unsigned char group, u32 *data,
>     308                                  unsigned char bytes)
>     309 {
>     310         const unsigned char *buf = cvt->buf;
>     311         struct ump_cvt_to_ump_bank *cc;
>     312         union snd_ump_midi2_msg *midi2 = (union snd_ump_midi2_msg *)data;
>     313         unsigned char status, channel;
>     314 
>     315         BUILD_BUG_ON(sizeof(union snd_ump_midi1_msg) != 4);
>     316         BUILD_BUG_ON(sizeof(union snd_ump_midi2_msg) != 8);
>     317 
>     318         /* for MIDI 1.0 UMP, it's easy, just pack it into UMP */
>     319         if (ump->info.protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI1) {
>     320                 data[0] = ump_compose(UMP_MSG_TYPE_MIDI1_CHANNEL_VOICE,
>     321                                       group, 0, buf[0]);
>     322                 data[0] |= buf[1] << 8;
>     323                 if (bytes > 2)
>     324                         data[0] |= buf[2];
>     325                 return 4;
>     326         }
>     327 
>     328         status = *buf >> 4;
>     329         channel = *buf & 0x0f;
>     330         cc = &cvt->bank[channel];
>     331 
>     332         /* special handling: treat note-on with 0 velocity as note-off */
>     333         if (status == UMP_MSG_STATUS_NOTE_ON && !buf[2])
>     334                 status = UMP_MSG_STATUS_NOTE_OFF;
> 
> This if statment
> 
>     335 
>     336         /* initialize the packet */
>     337         data[0] = ump_compose(UMP_MSG_TYPE_MIDI2_CHANNEL_VOICE,
>     338                               group, status, channel);
>     339         data[1] = 0;
>     340 
>     341         switch (status) {
>     342         case UMP_MSG_STATUS_NOTE_ON:
> --> 343                 if (!buf[2])
>     344                         status = UMP_MSG_STATUS_NOTE_OFF;
> 
> and this one are the same.  One could be deleted.

Correct.  I'll submit a fix patch.


Thanks!

Takashi