ALSA: hda - Protect the power-saving count with spinlock

To avoid some races.  Still not perfect, but now a bit safer.

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

2 files changed, 22 insertions, 2 deletions

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 8bd34320ef91..30a3d8ff978b 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1266,6 +1266,7 @@ int /*__devinit*/ snd_hda_codec_new(struct hda_bus *bus,
         snd_array_init(&codec->spdif_out, sizeof(struct hda_spdif_out), 16);
 
 #ifdef CONFIG_SND_HDA_POWER_SAVE
+        spin_lock_init(&codec->power_lock);
         INIT_DELAYED_WORK(&codec->power_work, hda_power_work);
         /* snd_hda_codec_new() marks the codec as power-up, and leave it as is.
          * the caller has to power down appropriatley after initialization
@@ -4292,12 +4293,16 @@ static void hda_power_work(struct work_struct *work)
                 container_of(work, struct hda_codec, power_work.work);
         struct hda_bus *bus = codec->bus;
 
+        spin_lock(&codec->power_lock);
         if (!codec->power_on || codec->power_count) {
                 codec->power_transition = 0;
+                spin_unlock(&codec->power_lock);
                 return;
         }
 
         trace_hda_power_down(codec);
+        spin_unlock(&codec->power_lock);
+
         hda_call_codec_suspend(codec);
         if (bus->ops.pm_notify)
                 bus->ops.pm_notify(bus);
@@ -4305,9 +4310,11 @@ static void hda_power_work(struct work_struct *work)
 
 static void hda_keep_power_on(struct hda_codec *codec)
 {
+        spin_lock(&codec->power_lock);
         codec->power_count++;
         codec->power_on = 1;
         codec->power_jiffies = jiffies;
+        spin_unlock(&codec->power_lock);
 }
 
 /* update the power on/off account with the current jiffies */
@@ -4332,20 +4339,28 @@ void snd_hda_power_up(struct hda_codec *codec)
 {
         struct hda_bus *bus = codec->bus;
 
+        spin_lock(&codec->power_lock);
         codec->power_count++;
-        if (codec->power_on || codec->power_transition)
+        if (codec->power_on || codec->power_transition) {
+                spin_unlock(&codec->power_lock);
                 return;
+        }
 
         trace_hda_power_up(codec);
         snd_hda_update_power_acct(codec);
         codec->power_on = 1;
         codec->power_jiffies = jiffies;
         codec->power_transition = 1; /* avoid reentrance */
+        spin_unlock(&codec->power_lock);
+
         if (bus->ops.pm_notify)
                 bus->ops.pm_notify(bus);
         hda_call_codec_resume(codec);
+
+        spin_lock(&codec->power_lock);
         cancel_delayed_work(&codec->power_work);
         codec->power_transition = 0;
+        spin_unlock(&codec->power_lock);
 }
 EXPORT_SYMBOL_HDA(snd_hda_power_up);
 
@@ -4361,14 +4376,18 @@ EXPORT_SYMBOL_HDA(snd_hda_power_up);
  */
 void snd_hda_power_down(struct hda_codec *codec)
 {
+        spin_lock(&codec->power_lock);
         --codec->power_count;
-        if (!codec->power_on || codec->power_count || codec->power_transition)
+        if (!codec->power_on || codec->power_count || codec->power_transition) {
+                spin_unlock(&codec->power_lock);
                 return;
+        }
         if (power_save(codec)) {
                 codec->power_transition = 1; /* avoid reentrance */
                 queue_delayed_work(codec->bus->workq, &codec->power_work,
                                 msecs_to_jiffies(power_save(codec) * 1000));
         }
+        spin_unlock(&codec->power_lock);
 }
 EXPORT_SYMBOL_HDA(snd_hda_power_down);
 
diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index 0fe64912cefc..77cd99531aae 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -867,6 +867,7 @@ struct hda_codec {
         unsigned long power_on_acct;
         unsigned long power_off_acct;
         unsigned long power_jiffies;
+        spinlock_t power_lock;
 #endif
 
         /* codec-specific additional proc output */