Commit b5fd12d6 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: seq: Correct unlock sequence at snd_seq_client_ioctl_unlock() 



The doubly unlock sequence at snd_seq_client_ioctl_unlock() is tricky.
I took a direct unref call since I thought it would avoid
misunderstanding, but rather this seems more confusing.  Let's use
snd_seq_client_unlock() consistently even if they look strange to be
called twice, and add more comments for avoiding reader's confusion.

Fixes: 6b580f52 ("ALSA: seq: Protect racy pool manipulation from OSS sequencer")
Reviewed-by: default avatarKai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 46f5710f

sound/core/seq/seq_clientmgr.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -191,6 +191,7 @@ bool snd_seq_client_ioctl_lock(int clientid) 
	if (!client)

	if (!client)

		return false;

		return false;

	mutex_lock(&client->ioctl_mutex);

	mutex_lock(&client->ioctl_mutex);

	/* The client isn't unrefed here; see snd_seq_client_ioctl_unlock() */

	return true;

	return true;

}

}

EXPORT_SYMBOL_GPL(snd_seq_client_ioctl_lock);

EXPORT_SYMBOL_GPL(snd_seq_client_ioctl_lock);
@@ -204,7 +205,11 @@ void snd_seq_client_ioctl_unlock(int clientid) 
	if (WARN_ON(!client))

	if (WARN_ON(!client))

		return;

		return;

	mutex_unlock(&client->ioctl_mutex);

	mutex_unlock(&client->ioctl_mutex);

	snd_use_lock_free(&client->use_lock);

	/* The doubly unrefs below are intentional; the first one releases the

	 * leftover from snd_seq_client_ioctl_lock() above, and the second one

	 * is for releasing snd_seq_client_use_ptr() in this function

	 */

	snd_seq_client_unlock(client);

	snd_seq_client_unlock(client);

	snd_seq_client_unlock(client);

}

}

EXPORT_SYMBOL_GPL(snd_seq_client_ioctl_unlock);

EXPORT_SYMBOL_GPL(snd_seq_client_ioctl_unlock);

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