ALSA: hda - Use own workqueue

snd-hda-intel driver used schedule_work() fot the delayed DMA pointer
updates, but this has several potential problems:
- it may block other eventsd works longer
- it may deadlock when probing fails and flush_scheduled_work() is
  called during probe callback (as probe callback itself could be
  invoked from eventd)

This patch adds an own workq for each driver instance to solve these
problems.

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

4 files changed, 21 insertions, 10 deletions

diff --git a/sound/pci/hda/hda_beep.c b/sound/pci/hda/hda_beep.c
index e00421c0d8b..960fd797038 100644
--- a/sound/pci/hda/hda_beep.c
+++ b/sound/pci/hda/hda_beep.c
@@ -135,7 +135,6 @@ void snd_hda_detach_beep_device(struct hda_codec *codec)
         struct hda_beep *beep = codec->beep;
         if (beep) {
                 cancel_work_sync(&beep->beep_work);
-                flush_scheduled_work();
 
                 input_unregister_device(beep->dev);
                 kfree(beep);
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index f80e5f3b97d..3c596da2b9b 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -373,7 +373,7 @@ int snd_hda_queue_unsol_event(struct hda_bus *bus, u32 res, u32 res_ex)
         unsol->queue[wp] = res;
         unsol->queue[wp + 1] = res_ex;
 
-        schedule_work(&unsol->work);
+        queue_work(bus->workq, &unsol->work);
 
         return 0;
 }
@@ -437,15 +437,17 @@ static int snd_hda_bus_free(struct hda_bus *bus)
 
         if (!bus)
                 return 0;
-        if (bus->unsol) {
-                flush_scheduled_work();
+        if (bus->workq)
+                flush_workqueue(bus->workq);
+        if (bus->unsol)
                 kfree(bus->unsol);
-        }
         list_for_each_entry_safe(codec, n, &bus->codec_list, list) {
                 snd_hda_codec_free(codec);
         }
         if (bus->ops.private_free)
                 bus->ops.private_free(bus);
+        if (bus->workq)
+                destroy_workqueue(bus->workq);
         kfree(bus);
         return 0;
 }
@@ -485,6 +487,7 @@ int /*__devinit*/ snd_hda_bus_new(struct snd_card *card,
 {
         struct hda_bus *bus;
         int err;
+        char qname[8];
         static struct snd_device_ops dev_ops = {
                 .dev_register = snd_hda_bus_dev_register,
                 .dev_free = snd_hda_bus_dev_free,
@@ -514,6 +517,14 @@ int /*__devinit*/ snd_hda_bus_new(struct snd_card *card,
         mutex_init(&bus->cmd_mutex);
         INIT_LIST_HEAD(&bus->codec_list);
 
+        snprintf(qname, sizeof(qname), "hda%d", card->number);
+        bus->workq = create_workqueue(qname);
+        if (!bus->workq) {
+                snd_printk(KERN_ERR "cannot create workqueue %s\n", qname);
+                kfree(bus);
+                return -ENOMEM;
+        }
+
         err = snd_device_new(card, SNDRV_DEV_BUS, bus, &dev_ops);
         if (err < 0) {
                 snd_hda_bus_free(bus);
@@ -684,7 +695,7 @@ static void snd_hda_codec_free(struct hda_codec *codec)
                 return;
 #ifdef CONFIG_SND_HDA_POWER_SAVE
         cancel_delayed_work(&codec->power_work);
-        flush_scheduled_work();
+        flush_workqueue(codec->bus->workq);
 #endif
         list_del(&codec->list);
         snd_array_free(&codec->mixers);
@@ -1273,7 +1284,7 @@ void snd_hda_codec_reset(struct hda_codec *codec)
 
 #ifdef CONFIG_SND_HDA_POWER_SAVE
         cancel_delayed_work(&codec->power_work);
-        flush_scheduled_work();
+        flush_workqueue(codec->bus->workq);
 #endif
         snd_hda_ctls_clear(codec);
         /* relase PCMs */
diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index e9c723e13e5..5810ef58840 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -614,6 +614,7 @@ struct hda_bus {
 
         /* unsolicited event queue */
         struct hda_bus_unsolicited *unsol;
+        struct workqueue_struct *workq; /* common workqueue for codecs */
 
         /* assigned PCMs */
         DECLARE_BITMAP(pcm_dev_bits, SNDRV_PCM_DEVICES);
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index f04de115ee1..11e791b965f 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -996,10 +996,11 @@ static irqreturn_t azx_interrupt(int irq, void *dev_id)
                                 spin_unlock(&chip->reg_lock);
                                 snd_pcm_period_elapsed(azx_dev->substream);
                                 spin_lock(&chip->reg_lock);
-                        } else {
+                        } else if (chip->bus && chip->bus->workq) {
                                 /* bogus IRQ, process it later */
                                 azx_dev->irq_pending = 1;
-                                schedule_work(&chip->irq_pending_work);
+                                queue_work(chip->bus->workq,
+                                           &chip->irq_pending_work);
                         }
                 }
         }
@@ -1741,7 +1742,6 @@ static void azx_clear_irq_pending(struct azx *chip)
         for (i = 0; i < chip->num_streams; i++)
                 chip->azx_dev[i].irq_pending = 0;
         spin_unlock_irq(&chip->reg_lock);
-        flush_scheduled_work();
 }
 
 static struct snd_pcm_ops azx_pcm_ops = {