From bde3e2880ff92f9956914afdd19648ccb20f487a Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Fri, 9 Oct 2015 08:10:29 +0900 Subject: [PATCH] ALSA: firewire-lib: avoid endless loop to transfer MIDI messages at fatal error Currently, when asynchronous transactions finish in error state and retries, work scheduling and work running also continues. This should be canceled at fatal error because it can cause endless loop. This commit enables to cancel transferring MIDI messages when transactions encounter fatal errors. This is achieved by setting error state. Signed-off-by: Takashi Sakamoto Signed-off-by: Takashi Iwai --- sound/firewire/lib.c | 11 +++++++++-- sound/firewire/lib.h | 8 ++++++-- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c index 9a98c7cd8744..edf1c8bd25a6 100644 --- a/sound/firewire/lib.c +++ b/sound/firewire/lib.c @@ -79,6 +79,9 @@ static void async_midi_port_callback(struct fw_card *card, int rcode, else if (!rcode_is_permanent_error(rcode)) /* To start next transaction immediately for recovery. */ port->next_ktime = ktime_set(0, 0); + else + /* Don't continue processing. */ + port->error = true; port->idling = true; @@ -94,8 +97,8 @@ static void midi_port_work(struct work_struct *work) int generation; int type; - /* Under transacting. */ - if (!port->idling) + /* Under transacting or error state. */ + if (!port->idling || port->error) return; /* Nothing to do. */ @@ -119,6 +122,9 @@ static void midi_port_work(struct work_struct *work) if (port->consume_bytes == 0) { port->next_ktime = ktime_set(0, 0); schedule_work(&port->work); + } else { + /* Fatal error. */ + port->error = true; } return; } @@ -178,6 +184,7 @@ int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port, port->fill = fill; port->idling = true; port->next_ktime = ktime_set(0, 0); + port->error = false; INIT_WORK(&port->work, midi_port_work); diff --git a/sound/firewire/lib.h b/sound/firewire/lib.h index 59e086587212..f3f6f84c48d6 100644 --- a/sound/firewire/lib.h +++ b/sound/firewire/lib.h @@ -32,6 +32,7 @@ struct snd_fw_async_midi_port { struct work_struct work; bool idling; ktime_t next_ktime; + bool error; u64 addr; struct fw_transaction transaction; @@ -58,8 +59,10 @@ static inline void snd_fw_async_midi_port_run(struct snd_fw_async_midi_port *port, struct snd_rawmidi_substream *substream) { - port->substream = substream; - schedule_work(&port->work); + if (!port->error) { + port->substream = substream; + schedule_work(&port->work); + } } /** @@ -70,6 +73,7 @@ static inline void snd_fw_async_midi_port_finish(struct snd_fw_async_midi_port *port) { port->substream = NULL; + port->error = false; } #endif -- 2.20.1