ALSA: fireworks: serialize transactions to update connections at bus reset
In IEC 61883-1, at bus-reset, applications can continue isochronous streaming by updating connections. In ALSA fireworks driver, the operation is executed in 'update' handler for bus driver. The connection resources are also changed in process contexts of PCM/MIDI applications. Therefore, bus-reset handling has race condition against connection. Current ALSA fireworks driver has a bug for the condition. This commit fixes the bug, by expand critical section with mutex. As a result, connection updating operation in bus-reset handler and connection changing operation in process context are serialized. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
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@ -301,7 +301,10 @@ static void efw_update(struct fw_unit *unit)
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struct snd_efw *efw = dev_get_drvdata(&unit->device);
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snd_efw_transaction_bus_reset(efw->unit);
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mutex_lock(&efw->mutex);
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snd_efw_stream_update_duplex(efw);
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mutex_unlock(&efw->mutex);
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}
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static void efw_remove(struct fw_unit *unit)
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@ -313,12 +313,10 @@ void snd_efw_stream_stop_duplex(struct snd_efw *efw)
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void snd_efw_stream_update_duplex(struct snd_efw *efw)
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{
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if ((cmp_connection_update(&efw->out_conn) < 0) ||
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(cmp_connection_update(&efw->in_conn) < 0)) {
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mutex_lock(&efw->mutex);
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if (cmp_connection_update(&efw->out_conn) < 0 ||
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cmp_connection_update(&efw->in_conn) < 0) {
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stop_stream(efw, &efw->rx_stream);
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stop_stream(efw, &efw->tx_stream);
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mutex_unlock(&efw->mutex);
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} else {
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amdtp_stream_update(&efw->rx_stream);
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amdtp_stream_update(&efw->tx_stream);
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