1 files changed, 7 insertions, 20 deletions

diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index 35707c04e61..62576af36f4 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -71,9 +71,6 @@ static struct list_head sclp_vt220_outqueue;
 /* Number of requests in outqueue */
 static int sclp_vt220_outqueue_count;
 
-/* Wait queue used to delay write requests while we've run out of buffers */
-static wait_queue_head_t sclp_vt220_waitq;
-
 /* Timer used for delaying write requests to merge subsequent messages into
  * a single buffer */
 static struct timer_list sclp_vt220_timer;
@@ -133,7 +130,6 @@ sclp_vt220_process_queue(struct sclp_vt220_request *request)
         } while (request && __sclp_vt220_emit(request));
         if (request == NULL && sclp_vt220_flush_later)
                 sclp_vt220_emit_current();
-        wake_up(&sclp_vt220_waitq);
         /* Check if the tty needs a wake up call */
         if (sclp_vt220_tty != NULL) {
                 tty_wakeup(sclp_vt220_tty);
@@ -383,7 +379,7 @@ sclp_vt220_timeout(unsigned long data)
  */
 static int
 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
-                   int convertlf, int may_schedule)
+                   int convertlf, int may_fail)
 {
         unsigned long flags;
         void *page;
@@ -395,15 +391,14 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
         overall_written = 0;
         spin_lock_irqsave(&sclp_vt220_lock, flags);
         do {
-                /* Create a sclp output buffer if none exists yet */
+                /* Create an sclp output buffer if none exists yet */
                 if (sclp_vt220_current_request == NULL) {
                         while (list_empty(&sclp_vt220_empty)) {
                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
-                                if (in_interrupt() || !may_schedule)
-                                        sclp_sync_wait();
+                                if (may_fail)
+                                        goto out;
                                 else
-                                        wait_event(sclp_vt220_waitq,
-                                                !list_empty(&sclp_vt220_empty));
+                                        sclp_sync_wait();
                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
                         }
                         page = (void *) sclp_vt220_empty.next;
@@ -437,6 +432,7 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
                 add_timer(&sclp_vt220_timer);
         }
         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
+out:
         return overall_written;
 }
 
@@ -520,19 +516,11 @@ sclp_vt220_close(struct tty_struct *tty, struct file *filp)
  * character to the tty device.  If the kernel uses this routine,
  * it must call the flush_chars() routine (if defined) when it is
  * done stuffing characters into the driver.
- *
- * NOTE: include/linux/tty_driver.h specifies that a character should be
- * ignored if there is no room in the queue. This driver implements a different
- * semantic in that it will block when there is no more room left.
- *
- * FIXME: putchar can currently be called from BH and other non blocking
- * handlers so  this semantic isn't a good idea.
  */
 static int
 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 {
-        __sclp_vt220_write(&ch, 1, 0, 0, 1);
-        return 1;
+        return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 }
 
 /*
@@ -653,7 +641,6 @@ static int __init __sclp_vt220_init(void)
         spin_lock_init(&sclp_vt220_lock);
         INIT_LIST_HEAD(&sclp_vt220_empty);
         INIT_LIST_HEAD(&sclp_vt220_outqueue);
-        init_waitqueue_head(&sclp_vt220_waitq);
         init_timer(&sclp_vt220_timer);
         sclp_vt220_current_request = NULL;
         sclp_vt220_buffered_chars = 0;