diff options
Diffstat (limited to 'drivers/s390/char/sclp_vt220.c')
| -rw-r--r-- | drivers/s390/char/sclp_vt220.c | 55 |
1 files changed, 45 insertions, 10 deletions
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index 5aaaa2ec8df..b9a9f721716 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -97,13 +97,16 @@ static void sclp_vt220_pm_event_fn(struct sclp_register *reg, static int __sclp_vt220_emit(struct sclp_vt220_request *request); static void sclp_vt220_emit_current(void); -/* Registration structure for our interest in SCLP event buffers */ +/* Registration structure for SCLP output event buffers */ static struct sclp_register sclp_vt220_register = { .send_mask = EVTYP_VT220MSG_MASK, + .pm_event_fn = sclp_vt220_pm_event_fn, +}; + +/* Registration structure for SCLP input event buffers */ +static struct sclp_register sclp_vt220_register_input = { .receive_mask = EVTYP_VT220MSG_MASK, - .state_change_fn = NULL, .receiver_fn = sclp_vt220_receiver_fn, - .pm_event_fn = sclp_vt220_pm_event_fn, }; @@ -362,6 +365,31 @@ sclp_vt220_timeout(unsigned long data) #define BUFFER_MAX_DELAY HZ/20 +/* + * Drop oldest console buffer if sclp_con_drop is set + */ +static int +sclp_vt220_drop_buffer(void) +{ + struct list_head *list; + struct sclp_vt220_request *request; + void *page; + + if (!sclp_console_drop) + return 0; + list = sclp_vt220_outqueue.next; + if (sclp_vt220_queue_running) + /* The first element is in I/O */ + list = list->next; + if (list == &sclp_vt220_outqueue) + return 0; + list_del(list); + request = list_entry(list, struct sclp_vt220_request, list); + page = request->sclp_req.sccb; + list_add_tail((struct list_head *) page, &sclp_vt220_empty); + return 1; +} + /* * Internal implementation of the write function. Write COUNT bytes of data * from memory at BUF @@ -390,12 +418,16 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, do { /* Create an sclp output buffer if none exists yet */ if (sclp_vt220_current_request == NULL) { + if (list_empty(&sclp_vt220_empty)) + sclp_console_full++; while (list_empty(&sclp_vt220_empty)) { - spin_unlock_irqrestore(&sclp_vt220_lock, flags); if (may_fail || sclp_vt220_suspended) goto out; - else - sclp_sync_wait(); + if (sclp_vt220_drop_buffer()) + break; + spin_unlock_irqrestore(&sclp_vt220_lock, flags); + + sclp_sync_wait(); spin_lock_irqsave(&sclp_vt220_lock, flags); } page = (void *) sclp_vt220_empty.next; @@ -428,8 +460,8 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY; add_timer(&sclp_vt220_timer); } - spin_unlock_irqrestore(&sclp_vt220_lock, flags); out: + spin_unlock_irqrestore(&sclp_vt220_lock, flags); return overall_written; } @@ -686,9 +718,14 @@ static int __init sclp_vt220_tty_init(void) rc = tty_register_driver(driver); if (rc) goto out_init; + rc = sclp_register(&sclp_vt220_register_input); + if (rc) + goto out_reg; sclp_vt220_driver = driver; return 0; +out_reg: + tty_unregister_driver(driver); out_init: __sclp_vt220_cleanup(); out_driver: @@ -801,9 +838,7 @@ sclp_vt220_con_init(void) { int rc; - if (!CONSOLE_IS_SCLP) - return 0; - rc = __sclp_vt220_init(MAX_CONSOLE_PAGES); + rc = __sclp_vt220_init(sclp_console_pages); if (rc) return rc; /* Attach linux console */ |