[alsa-devel] [PATCH] [18/29] ALSA: dice: fix locking

[Clemens Ladisch]

From: Stefan Richter <stefanr at s5r6.in-berlin.de>

Avoid a lock inversion between dice->mutex and pcm->open_mutex.

Signed-off-by: Stefan Richter <stefanr at s5r6.in-berlin.de>
Signed-off-by: Clemens Ladisch <clemens at ladisch.de>
---
 sound/firewire/dice.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/firewire/dice.c b/sound/firewire/dice.c
index 2d198ae..2d3a04e 100644
--- a/sound/firewire/dice.c
+++ b/sound/firewire/dice.c
@@ -981,12 +981,12 @@ static void dice_remove(struct fw_unit *unit)
 {
 	struct dice *dice = dev_get_drvdata(&unit->device);

-	mutex_lock(&dice->mutex);
-
 	amdtp_out_stream_pcm_abort(&dice->stream);

 	snd_card_disconnect(dice->card);

+	mutex_lock(&dice->mutex);
+
 	dice_stream_stop(dice);
 	dice_owner_clear(dice);

@@ -999,8 +999,6 @@ static void dice_bus_reset(struct fw_unit *unit)
 {
 	struct dice *dice = dev_get_drvdata(&unit->device);

-	mutex_lock(&dice->mutex);
-
 	/*
 	 * On a bus reset, the DICE firmware disables streaming and then goes
 	 * off contemplating its own navel for hundreds of milliseconds before
@@ -1011,6 +1009,8 @@ static void dice_bus_reset(struct fw_unit *unit)
 	 */
 	amdtp_out_stream_pcm_abort(&dice->stream);

+	mutex_lock(&dice->mutex);
+
 	dice->global_enabled = false;
 	dice_stream_stop_packets(dice);