[PATCH 3.16 254/305] ALSA: usb-audio: Replace probing flag with active refcount

[Ben Hutchings]

3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <ti...@suse.de>

commit a6da499b76b1a75412f047ac388e9ffd69a5c55b upstream.

We can use active refcount for preventing autopm during probe.

Signed-off-by: Takashi Iwai <ti...@suse.de>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 sound/usb/card.c     | 12 ++++--------
 sound/usb/usbaudio.h |  1 -
 2 files changed, 4 insertions(+), 9 deletions(-)

--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -402,7 +402,7 @@ static int snd_usb_audio_create(struct u
        chip->card = card;
        chip->setup = device_setup[idx];
        chip->autoclock = autoclock;
-       chip->probing = 1;
+       atomic_set(&chip->active, 1); /* avoid autopm during probing */
        atomic_set(&chip->usage_count, 0);
        atomic_set(&chip->shutdown, 0);
 
@@ -532,7 +532,7 @@ snd_usb_audio_probe(struct usb_device *d
                                goto __error;
                        }
                        chip = usb_chip[i];
-                       chip->probing = 1;
+                       atomic_inc(&chip->active); /* avoid autopm */
                        break;
                }
        }
@@ -588,7 +588,7 @@ snd_usb_audio_probe(struct usb_device *d
 
        usb_chip[chip->index] = chip;
        chip->num_interfaces++;
-       chip->probing = 0;
+       atomic_dec(&chip->active);
        mutex_unlock(&register_mutex);
        return chip;
 
@@ -596,7 +596,7 @@ snd_usb_audio_probe(struct usb_device *d
        if (chip) {
                if (!chip->num_interfaces)
                        snd_card_free(chip->card);
-               chip->probing = 0;
+               atomic_dec(&chip->active);
        }
        mutex_unlock(&register_mutex);
  __err_val:
@@ -712,8 +712,6 @@ int snd_usb_autoresume(struct snd_usb_au
 {
        if (atomic_read(&chip->shutdown))
                return -EIO;
-       if (chip->probing)
-               return 0;
        if (atomic_inc_return(&chip->active) == 1)
                return usb_autopm_get_interface(chip->pm_intf);
        return 0;
@@ -721,8 +719,6 @@ int snd_usb_autoresume(struct snd_usb_au
 
 void snd_usb_autosuspend(struct snd_usb_audio *chip)
 {
-       if (chip->probing)
-               return;
        if (atomic_dec_and_test(&chip->active))
                usb_autopm_put_interface(chip->pm_intf);
 }
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -37,7 +37,6 @@ struct snd_usb_audio {
        struct usb_interface *pm_intf;
        u32 usb_id;
        struct mutex mutex;
-       unsigned int probing:1;
        unsigned int autosuspended:1;   
        atomic_t active;
        atomic_t shutdown;