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: 6b580f523172 ("ALSA: seq: Protect racy pool manipulation from OSS sequencer")
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
sound/core/seq/seq_clientmgr.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c
index 3acd80e718f2..c0227a672442 100644
--- a/sound/core/seq/seq_clientmgr.c
+++ b/sound/core/seq/seq_clientmgr.c
@@ -191,6 +191,7 @@ bool snd_seq_client_ioctl_lock(int clientid)
if (!client)
return false;
mutex_lock(&client->ioctl_mutex);
+ /* The client isn't unrefed here; see snd_seq_client_ioctl_unlock() */
return true;
}
EXPORT_SYMBOL_GPL(snd_seq_client_ioctl_lock);
@@ -204,7 +205,11 @@ void snd_seq_client_ioctl_unlock(int clientid)
if (WARN_ON(!client))
return;
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);
}
EXPORT_SYMBOL_GPL(snd_seq_client_ioctl_unlock);
--
2.16.4
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