isdn: divert, hysdn: fix interruptible_sleep_on race

These two drivers use identical code for their procfs status
file handling, which contains a small race against status
data becoming available while reading the file.

This uses wait_event_interruptible instead to fix this
particular race and eventually get rid of all sleep_on
instances. There seems to be another race involving
multiple concurrent readers of the same procfs file, which
I don't try to fix here.

Signed-off-by: Arnd Bergmann <[e-mail]>
Cc: Karsten Keil <[e-mail]>
Cc: [e-mail]
Signed-off-by: David S. Miller <[e-mail]>

drivers/isdn/divert/divert_procfs.c

···
 	struct divert_info *inf;
 	int len;
 
-	if (!*((struct divert_info **) file->private_data)) {
+	if (!(inf = *((struct divert_info **) file->private_data))) {
 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;
-		interruptible_sleep_on(&(rd_queue));
+		wait_event_interruptible(rd_queue, (inf =
+			*((struct divert_info **) file->private_data)));
 	}
-	if (!(inf = *((struct divert_info **) file->private_data)))
+	if (!inf)
 		return (0);
 
 	inf->usage_cnt--;	/* new usage count */

drivers/isdn/hysdn/hysdn_proclog.c

···
 	int len;
 	hysdn_card *card = PDE_DATA(file_inode(file));
 
-	if (!*((struct log_data **) file->private_data)) {
+	if (!(inf = *((struct log_data **) file->private_data))) {
 		struct procdata *pd = card->proclog;
 		if (file->f_flags & O_NONBLOCK)
 			return (-EAGAIN);
 
-		interruptible_sleep_on(&(pd->rd_queue));
+		wait_event_interruptible(pd->rd_queue, (inf =
+				*((struct log_data **) file->private_data)));
 	}
-	if (!(inf = *((struct log_data **) file->private_data)))
+	if (!inf)
 		return (0);
 
 	inf->usage_cnt--;	/* new usage count */