diff options
Diffstat (limited to 'drivers/s390/char/sclp_vt220.c')
| -rw-r--r-- | drivers/s390/char/sclp_vt220.c | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index 5aaaa2ec8df4..4eed38cd0af6 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -362,6 +362,31 @@ 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 +415,16 @@ __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 +457,8 @@ __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; } @@ -803,7 +832,7 @@ sclp_vt220_con_init(void) 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 */ |