ALSA: hda - Don't register a cb func if it is registered already

If the caller of enable_callback_mst() passes a cb func, the callee
function will malloc memory and link this cb func to the list
unconditionally. This will introduce problem if caller is in the
hda_codec_ops.init() since the init() will be repeatedly called in the
codec rt_resume().

So far, the patch_hdmi.c and patch_ca0132.c call enable_callback_mst()
in the hda_codec_ops.init().

Signed-off-by: Hui Wang <hui.wang@canonical.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200930055146.5665-1-hui.wang@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_jack.c b/sound/pci/hda/hda_jack.c
index 02cc682caa55a4c5ab6b0ca2aa8a02d008ac00ed..ded4813f8b546b4bf360d755754b87dcd70371ff 100644 (file)
--- a/sound/pci/hda/hda_jack.c
+++ b/sound/pci/hda/hda_jack.c
@@ -275,6 +275,18 @@ int snd_hda_jack_detect_state_mst(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_GPL(snd_hda_jack_detect_state_mst);
 
+static bool func_is_already_in_callback_list(struct hda_jack_tbl *jack,
+                                            hda_jack_callback_fn func)
+{
+       struct hda_jack_callback *cb;
+
+       for (cb = jack->callback; cb; cb = cb->next) {
+               if (cb->func == func)
+                       return true;
+       }
+       return false;
+}
+
 /**
  * snd_hda_jack_detect_enable_mst - enable the jack-detection
  * @codec: the HDA codec
@@ -297,7 +309,7 @@ snd_hda_jack_detect_enable_callback_mst(struct hda_codec *codec, hda_nid_t nid,
        jack = snd_hda_jack_tbl_new(codec, nid, dev_id);
        if (!jack)
                return ERR_PTR(-ENOMEM);
-       if (func) {
+       if (func && !func_is_already_in_callback_list(jack, func)) {
                callback = kzalloc(sizeof(*callback), GFP_KERNEL);
                if (!callback)
                        return ERR_PTR(-ENOMEM);