ALSA: timer: Unify master/slave linking code

The code in both snd_timer_check_master() and snd_timer_check_slave()
are almost identical, both check whether the master/slave link and
does linkage.  Factor out the common code and call it from both
functions for readability.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20191107192008.32331-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/timer.c b/sound/core/timer.c
index 013f0e69ff0f719fc1d090cd10a619a7bf47734a..21c2d25e4074aa2ac2544297ac2ed284a4548d20 100644 (file)
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -163,6 +163,28 @@ static void snd_timer_request(struct snd_timer_id *tid)
 
 #endif
 
+/* move the slave if it belongs to the master; return 1 if match */
+static int check_matching_master_slave(struct snd_timer_instance *master,
+                                      struct snd_timer_instance *slave)
+{
+       if (slave->slave_class != master->slave_class ||
+           slave->slave_id != master->slave_id)
+               return 0;
+       if (master->timer->num_instances >= master->timer->max_instances)
+               return -EBUSY;
+       list_move_tail(&slave->open_list, &master->slave_list_head);
+       master->timer->num_instances++;
+       spin_lock_irq(&slave_active_lock);
+       spin_lock(&master->timer->lock);
+       slave->master = master;
+       slave->timer = master->timer;
+       if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
+               list_add_tail(&slave->active_list, &master->slave_active_head);
+       spin_unlock(&master->timer->lock);
+       spin_unlock_irq(&slave_active_lock);
+       return 1;
+}
+
 /*
  * look for a master instance matching with the slave id of the given slave.
  * when found, relink the open_link of the slave.
@@ -173,27 +195,18 @@ static int snd_timer_check_slave(struct snd_timer_instance *slave)
 {
        struct snd_timer *timer;
        struct snd_timer_instance *master;
+       int err = 0;
 
        /* FIXME: it's really dumb to look up all entries.. */
        list_for_each_entry(timer, &snd_timer_list, device_list) {
                list_for_each_entry(master, &timer->open_list_head, open_list) {
-                       if (slave->slave_class == master->slave_class &&
-                           slave->slave_id == master->slave_id) {
-                               if (master->timer->num_instances >=
-                                   master->timer->max_instances)
-                                       return -EBUSY;
-                               list_move_tail(&slave->open_list,
-                                              &master->slave_list_head);
-                               master->timer->num_instances++;
-                               spin_lock_irq(&slave_active_lock);
-                               slave->master = master;
-                               slave->timer = master->timer;
-                               spin_unlock_irq(&slave_active_lock);
-                               return 0;
-                       }
+                       err = check_matching_master_slave(master, slave);
+                       if (err != 0) /* match found or error */
+                               goto out;
                }
        }
-       return 0;
+ out:
+       return err < 0 ? err : 0;
 }
 
 /*
@@ -205,28 +218,15 @@ static int snd_timer_check_slave(struct snd_timer_instance *slave)
 static int snd_timer_check_master(struct snd_timer_instance *master)
 {
        struct snd_timer_instance *slave, *tmp;
+       int err = 0;
 
        /* check all pending slaves */
        list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {
-               if (slave->slave_class == master->slave_class &&
-                   slave->slave_id == master->slave_id) {
-                       if (master->timer->num_instances >=
-                           master->timer->max_instances)
-                               return -EBUSY;
-                       list_move_tail(&slave->open_list, &master->slave_list_head);
-                       master->timer->num_instances++;
-                       spin_lock_irq(&slave_active_lock);
-                       spin_lock(&master->timer->lock);
-                       slave->master = master;
-                       slave->timer = master->timer;
-                       if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
-                               list_add_tail(&slave->active_list,
-                                             &master->slave_active_head);
-                       spin_unlock(&master->timer->lock);
-                       spin_unlock_irq(&slave_active_lock);
-               }
+               err = check_matching_master_slave(master, slave);
+               if (err < 0)
+                       break;
        }
-       return 0;
+       return err < 0 ? err : 0;
 }
 
 static int snd_timer_close_locked(struct snd_timer_instance *timeri,