ALSA: hda - Add pseudo device-locking for clear/reconfig

Added the pseudo device-locking using card->shutdown flag to avoid
the crash via clear/reconfig during operations.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index a13480f..5dceee8 100644 (file)
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1445,9 +1445,52 @@ void snd_hda_ctls_clear(struct hda_codec *codec)
        snd_array_free(&codec->mixers);
 }
 
-void snd_hda_codec_reset(struct hda_codec *codec)
+/* pseudo device locking
+ * toggle card->shutdown to allow/disallow the device access (as a hack)
+ */
+static int hda_lock_devices(struct snd_card *card)
 {
-       int i;
+       spin_lock(&card->files_lock);
+       if (card->shutdown) {
+               spin_unlock(&card->files_lock);
+               return -EINVAL;
+       }
+       card->shutdown = 1;
+       spin_unlock(&card->files_lock);
+       return 0;
+}
+
+static void hda_unlock_devices(struct snd_card *card)
+{
+       spin_lock(&card->files_lock);
+       card->shutdown = 0;
+       spin_unlock(&card->files_lock);
+}
+
+int snd_hda_codec_reset(struct hda_codec *codec)
+{
+       struct snd_card *card = codec->bus->card;
+       int i, pcm;
+
+       if (hda_lock_devices(card) < 0)
+               return -EBUSY;
+       /* check whether the codec isn't used by any mixer or PCM streams */
+       if (!list_empty(&card->ctl_files)) {
+               hda_unlock_devices(card);
+               return -EBUSY;
+       }
+       for (pcm = 0; pcm < codec->num_pcms; pcm++) {
+               struct hda_pcm *cpcm = &codec->pcm_info[pcm];
+               if (!cpcm->pcm)
+                       continue;
+               if (cpcm->pcm->streams[0].substream_opened ||
+                   cpcm->pcm->streams[1].substream_opened) {
+                       hda_unlock_devices(card);
+                       return -EBUSY;
+               }
+       }
+
+       /* OK, let it free */
 
 #ifdef CONFIG_SND_HDA_POWER_SAVE
        cancel_delayed_work(&codec->power_work);
@@ -1457,8 +1500,7 @@ void snd_hda_codec_reset(struct hda_codec *codec)
        /* relase PCMs */
        for (i = 0; i < codec->num_pcms; i++) {
                if (codec->pcm_info[i].pcm) {
-                       snd_device_free(codec->bus->card,
-                                       codec->pcm_info[i].pcm);
+                       snd_device_free(card, codec->pcm_info[i].pcm);
                        clear_bit(codec->pcm_info[i].device,
                                  codec->bus->pcm_dev_bits);
                }
@@ -1479,6 +1521,10 @@ void snd_hda_codec_reset(struct hda_codec *codec)
        codec->preset = NULL;
        module_put(codec->owner);
        codec->owner = NULL;
+
+       /* allow device access again */
+       hda_unlock_devices(card);
+       return 0;
 }
 #endif /* CONFIG_SND_HDA_RECONFIG */
 

diff --git a/sound/pci/hda/hda_hwdep.c b/sound/pci/hda/hda_hwdep.c
index c660383..4af484b 100644 (file)
--- a/sound/pci/hda/hda_hwdep.c
+++ b/sound/pci/hda/hda_hwdep.c
@@ -155,7 +155,13 @@ int /*__devinit*/ snd_hda_create_hwdep(struct hda_codec *codec)
 
 static int clear_codec(struct hda_codec *codec)
 {
-       snd_hda_codec_reset(codec);
+       int err;
+
+       err = snd_hda_codec_reset(codec);
+       if (err < 0) {
+               snd_printk(KERN_ERR "The codec is being used, can't free.\n");
+               return err;
+       }
        clear_hwdep_elements(codec);
        return 0;
 }
@@ -165,7 +171,12 @@ static int reconfig_codec(struct hda_codec *codec)
        int err;
 
        snd_printk(KERN_INFO "hda-codec: reconfiguring\n");
-       snd_hda_codec_reset(codec);
+       err = snd_hda_codec_reset(codec);
+       if (err < 0) {
+               snd_printk(KERN_ERR
+                          "The codec is being used, can't reconfigure.\n");
+               return err;
+       }
        err = snd_hda_codec_configure(codec);
        if (err < 0)
                return err;

diff --git a/sound/pci/hda/hda_local.h b/sound/pci/hda/hda_local.h
index 84e2cf6..4bd82a3 100644 (file)
--- a/sound/pci/hda/hda_local.h
+++ b/sound/pci/hda/hda_local.h
@@ -98,7 +98,7 @@ struct snd_kcontrol *snd_hda_find_mixer_ctl(struct hda_codec *codec,
                                            const char *name);
 int snd_hda_add_vmaster(struct hda_codec *codec, char *name,
                        unsigned int *tlv, const char **slaves);
-void snd_hda_codec_reset(struct hda_codec *codec);
+int snd_hda_codec_reset(struct hda_codec *codec);
 int snd_hda_codec_configure(struct hda_codec *codec);
 
 /* amp value bits */