ALSA: control: Provide a helper to look for the preferred subdevice

Instead of open-coding the search over the control file loop, provide
a helper function for the preferred subdevice assigned to the current
process.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

4 files changed, 38 insertions, 29 deletions

diff --git a/include/sound/control.h b/include/sound/control.h
index 042613938a1d..75f3054023f7 100644
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -93,12 +93,17 @@ struct snd_kctl_event {
 
 struct pid;
 
+enum {
+        SND_CTL_SUBDEV_PCM,
+        SND_CTL_SUBDEV_RAWMIDI,
+        SND_CTL_SUBDEV_ITEMS,
+};
+
 struct snd_ctl_file {
         struct list_head list;          /* list of all control files */
         struct snd_card *card;
         struct pid *pid;
-        int prefer_pcm_subdevice;
-        int prefer_rawmidi_subdevice;
+        int preferred_subdevice[SND_CTL_SUBDEV_ITEMS];
         wait_queue_head_t change_sleep;
         spinlock_t read_lock;
         struct fasync_struct *fasync;
@@ -138,6 +143,8 @@ int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn);
 #define snd_ctl_unregister_ioctl_compat(fcn)
 #endif
 
+int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type);
+
 static inline unsigned int snd_ctl_get_ioffnum(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id)
 {
         return id->numid - kctl->id.numid;
diff --git a/sound/core/control.c b/sound/core/control.c
index bb96a467e88d..cd246a0bcd55 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -50,7 +50,7 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
         unsigned long flags;
         struct snd_card *card;
         struct snd_ctl_file *ctl;
-        int err;
+        int i, err;
 
         err = nonseekable_open(inode, file);
         if (err < 0)
@@ -79,8 +79,8 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
         init_waitqueue_head(&ctl->change_sleep);
         spin_lock_init(&ctl->read_lock);
         ctl->card = card;
-        ctl->prefer_pcm_subdevice = -1;
-        ctl->prefer_rawmidi_subdevice = -1;
+        for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
+                ctl->preferred_subdevice[i] = -1;
         ctl->pid = get_pid(task_pid(current));
         file->private_data = ctl;
         write_lock_irqsave(&card->ctl_files_rwlock, flags);
@@ -1607,6 +1607,27 @@ static int snd_ctl_fasync(int fd, struct file * file, int on)
         return fasync_helper(fd, file, on, &ctl->fasync);
 }
 
+/* return the preferred subdevice number if already assigned;
+ * otherwise return -1
+ */
+int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
+{
+        struct snd_ctl_file *kctl;
+        int subdevice = -1;
+
+        read_lock(&card->ctl_files_rwlock);
+        list_for_each_entry(kctl, &card->ctl_files, list) {
+                if (kctl->pid == task_pid(current)) {
+                        subdevice = kctl->preferred_subdevice[type];
+                        if (subdevice != -1)
+                                break;
+                }
+        }
+        read_unlock(&card->ctl_files_rwlock);
+        return subdevice;
+}
+EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
+
 /*
  * ioctl32 compat
  */
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index dba5180e5b80..1b7c473720fa 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -161,7 +161,7 @@ static int snd_pcm_control_ioctl(struct snd_card *card,
                         
                         if (get_user(val, (int __user *)arg))
                                 return -EFAULT;
-                        control->prefer_pcm_subdevice = val;
+                        control->preferred_subdevice[SND_CTL_SUBDEV_PCM] = val;
                         return 0;
                 }
         }
@@ -901,9 +901,8 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
         struct snd_pcm_str * pstr;
         struct snd_pcm_substream *substream;
         struct snd_pcm_runtime *runtime;
-        struct snd_ctl_file *kctl;
         struct snd_card *card;
-        int prefer_subdevice = -1;
+        int prefer_subdevice;
         size_t size;
 
         if (snd_BUG_ON(!pcm || !rsubstream))
@@ -914,15 +913,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
                 return -ENODEV;
 
         card = pcm->card;
-        read_lock(&card->ctl_files_rwlock);
-        list_for_each_entry(kctl, &card->ctl_files, list) {
-                if (kctl->pid == task_pid(current)) {
-                        prefer_subdevice = kctl->prefer_pcm_subdevice;
-                        if (prefer_subdevice != -1)
-                                break;
-                }
-        }
-        read_unlock(&card->ctl_files_rwlock);
+        prefer_subdevice = snd_ctl_get_preferred_subdevice(card, SND_CTL_SUBDEV_PCM);
 
         switch (stream) {
         case SNDRV_PCM_STREAM_PLAYBACK:
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 6fc71a4c8a51..be18162c380f 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -369,7 +369,6 @@ static int snd_rawmidi_open(struct inode *inode, struct file *file)
         struct snd_rawmidi *rmidi;
         struct snd_rawmidi_file *rawmidi_file = NULL;
         wait_queue_t wait;
-        struct snd_ctl_file *kctl;
 
         if ((file->f_flags & O_APPEND) && !(file->f_flags & O_NONBLOCK)) 
                 return -EINVAL;         /* invalid combination */
@@ -413,16 +412,7 @@ static int snd_rawmidi_open(struct inode *inode, struct file *file)
         init_waitqueue_entry(&wait, current);
         add_wait_queue(&rmidi->open_wait, &wait);
         while (1) {
-                subdevice = -1;
-                read_lock(&card->ctl_files_rwlock);
-                list_for_each_entry(kctl, &card->ctl_files, list) {
-                        if (kctl->pid == task_pid(current)) {
-                                subdevice = kctl->prefer_rawmidi_subdevice;
-                                if (subdevice != -1)
-                                        break;
-                        }
-                }
-                read_unlock(&card->ctl_files_rwlock);
+                subdevice = snd_ctl_get_preferred_subdevice(card, SND_CTL_SUBDEV_RAWMIDI);
                 err = rawmidi_open_priv(rmidi, subdevice, fflags, rawmidi_file);
                 if (err >= 0)
                         break;
@@ -862,7 +852,7 @@ static int snd_rawmidi_control_ioctl(struct snd_card *card,
                 
                 if (get_user(val, (int __user *)argp))
                         return -EFAULT;
-                control->prefer_rawmidi_subdevice = val;
+                control->preferred_subdevice[SND_CTL_SUBDEV_RAWMIDI] = val;
                 return 0;
         }
         case SNDRV_CTL_IOCTL_RAWMIDI_INFO: