ALSA: firewire: use managed-resource of fw unit device for private data

At present, private data of each driver in ALSA firewire stack is
allocated/freed by kernel slab allocator for corresponding unit on
IEEE 1394 bus. In this case, resource-managed slab allocator is
available to release memory object automatically just before releasing
device structure for the unit. This idea can prevent runtime from
memory leak due to programming mistakes.

This commit uses the allocator for the private data. These drivers
already use reference counter to maintain lifetime of device structure
for the unit by a pair of fw_unit_get()/fw_unit_put(). The private data
is safely released in a callback of 'struct snd_card.private_free().

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 2 insertions, 4 deletions

diff --git a/sound/firewire/fireworks/fireworks.c b/sound/firewire/fireworks/fireworks.c
index f2d073365cf6..2ff7b9cff9b0 100644
--- a/sound/firewire/fireworks/fireworks.c
+++ b/sound/firewire/fireworks/fireworks.c
@@ -188,12 +188,11 @@ static void efw_free(struct snd_efw *efw)
 {
 	snd_efw_stream_destroy_duplex(efw);
 	snd_efw_transaction_remove_instance(efw);
-	fw_unit_put(efw->unit);
 
 	kfree(efw->resp_buf);
 
 	mutex_destroy(&efw->mutex);
-	kfree(efw);
+	fw_unit_put(efw->unit);
 }
 
 /*
@@ -312,10 +311,9 @@ efw_probe(struct fw_unit *unit, const struct ieee1394_device_id *entry)
 {
 	struct snd_efw *efw;
 
-	efw = kzalloc(sizeof(struct snd_efw), GFP_KERNEL);
+	efw = devm_kzalloc(&unit->device, sizeof(struct snd_efw), GFP_KERNEL);
 	if (efw == NULL)
 		return -ENOMEM;
-
 	efw->unit = fw_unit_get(unit);
 	dev_set_drvdata(&unit->device, efw);