[ALSA] timer - added tread semaphore

Timer Midlevel


Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 37 insertions, 20 deletions

diff --git a/sound/core/timer.c b/sound/core/timer.c
index fa762ca439be..be6d37af76d8 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -69,6 +69,7 @@ typedef struct {
         struct timespec tstamp;         /* trigger tstamp */
         wait_queue_head_t qchange_sleep;
         struct fasync_struct *fasync;
+        struct semaphore tread_sem;
 } snd_timer_user_t;
 
 /* list of timers */
@@ -1208,6 +1209,7 @@ static int snd_timer_user_open(struct inode *inode, struct file *file)
                 return -ENOMEM;
         spin_lock_init(&tu->qlock);
         init_waitqueue_head(&tu->qchange_sleep);
+        init_MUTEX(&tu->tread_sem);
         tu->ticks = 1;
         tu->queue_size = 128;
         tu->queue = (snd_timer_read_t *)kmalloc(tu->queue_size * sizeof(snd_timer_read_t), GFP_KERNEL);
@@ -1454,18 +1456,23 @@ static int snd_timer_user_tselect(struct file *file, snd_timer_select_t __user *
         snd_timer_user_t *tu;
         snd_timer_select_t tselect;
         char str[32];
-        int err;
+        int err = 0;
         
         tu = file->private_data;
-        if (tu->timeri)
+        down(&tu->tread_sem);
+        if (tu->timeri) {
                 snd_timer_close(tu->timeri);
-        if (copy_from_user(&tselect, _tselect, sizeof(tselect)))
-                return -EFAULT;
+                tu->timeri = NULL;
+        }
+        if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
+                err = -EFAULT;
+                goto __err;
+        }
         sprintf(str, "application %i", current->pid);
         if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
                 tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
         if ((err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid)) < 0)
-                return err;
+                goto __err;
 
         if (tu->queue) {
                 kfree(tu->queue);
@@ -1477,23 +1484,27 @@ static int snd_timer_user_tselect(struct file *file, snd_timer_select_t __user *
         }
         if (tu->tread) {
                 tu->tqueue = (snd_timer_tread_t *)kmalloc(tu->queue_size * sizeof(snd_timer_tread_t), GFP_KERNEL);
-                if (tu->tqueue == NULL) {
-                        snd_timer_close(tu->timeri);
-                        return -ENOMEM;
-                }
+                if (tu->tqueue == NULL)
+                        err = -ENOMEM;
         } else {
                 tu->queue = (snd_timer_read_t *)kmalloc(tu->queue_size * sizeof(snd_timer_read_t), GFP_KERNEL);
-                if (tu->queue == NULL) {
-                        snd_timer_close(tu->timeri);
-                        return -ENOMEM;
-                }
+                if (tu->queue == NULL)
+                        err = -ENOMEM;
         }
         
-        tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
-        tu->timeri->callback = tu->tread ? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
-        tu->timeri->ccallback = snd_timer_user_ccallback;
-        tu->timeri->callback_data = (void *)tu;
-        return 0;
+        if (err < 0) {
+                snd_timer_close(tu->timeri);
+                tu->timeri = NULL;
+        } else {
+                tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
+                tu->timeri->callback = tu->tread ? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
+                tu->timeri->ccallback = snd_timer_user_ccallback;
+                tu->timeri->callback_data = (void *)tu;
+        }
+
+      __err:
+        up(&tu->tread_sem);
+        return err;
 }
 
 static int snd_timer_user_info(struct file *file, snd_timer_info_t __user *_info)
@@ -1685,11 +1696,17 @@ static long snd_timer_user_ioctl(struct file *file, unsigned int cmd, unsigned l
         {
                 int xarg;
                 
-                if (tu->timeri)         /* too late */
+                down(&tu->tread_sem);
+                if (tu->timeri) {       /* too late */
+                        up(&tu->tread_sem);
                         return -EBUSY;
-                if (get_user(xarg, p))
+                }
+                if (get_user(xarg, p)) {
+                        up(&tu->tread_sem);
                         return -EFAULT;
+                }
                 tu->tread = xarg ? 1 : 0;
+                up(&tu->tread_sem);
                 return 0;
         }
         case SNDRV_TIMER_IOCTL_GINFO: