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path: root/drivers/s390/char/sclp_vt220.c
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Diffstat (limited to 'drivers/s390/char/sclp_vt220.c')
-rw-r--r--drivers/s390/char/sclp_vt220.c27
1 files changed, 7 insertions, 20 deletions
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index 35707c04e613..62576af36f47 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;