[alsa-devel] [PATCH 2/3] ALSA: tascam: improve loop condition to filling MIDI bytes in transaction

[Takashi Sakamoto]

On Oct 18 2015 19:10, Takashi Iwai wrote:
> On Sun, 18 Oct 2015 12:02:17 +0200,
> Takashi Sakamoto wrote:
>>
>> It includes meaningless condition. This commit improve it.
>>
>> Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
>> ---
>>  sound/firewire/tascam/tascam-transaction.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/sound/firewire/tascam/tascam-transaction.c b/sound/firewire/tascam/tascam-transaction.c
>> index 7fcee81..4ffaa8a 100644
>> --- a/sound/firewire/tascam/tascam-transaction.c
>> +++ b/sound/firewire/tascam/tascam-transaction.c
>> @@ -74,7 +74,7 @@ static int fill_message(struct snd_rawmidi_substream *substream, u8 *buf)
>>  	/* On exclusive message. */
>>  	if (tscm->on_sysex[port]) {
>>  		/* Seek the end of exclusives. */
>> -		for (i = 1; i < 4 || i < len; ++i) {
>> +		for (i = 1; i < len + 1; ++i) {
> 
> This doesn't look like an improvement...
> The fix should be rather like:
> 		for (i = 1; i < 4 && i < len; ++i) {

The 'len' variable is assigned to the return value of
snd_rawmidi_transmit_peek(). The third argument to call this function is
3, thus the value of this variable equals to or is less than 3.

The aim of this loop is to find EOX (end of exclusive) byte in retrieved
bytes, then break the loop.The index goes from 1 to the end of retrieved
bytes. Thus, 'i < 4 || i < len' is not so proper, here.


Thanks

Takashi Sakamoto