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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2009-06-12 10:26:31 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2009-06-12 10:27:33 +0200
commit205d7ab9c9af6847dda30650a0b8f98555a20654 (patch)
treeb77071becdd91a01ba2b30b3bdd79388f738b96b /drivers/s390/char/tty3270.c
parentfcf7581f7ca82e63e4e137be77c342a4e4ec8401 (diff)
[S390] 3270: lock dependency fixes
Lockdep found a problem with the lock order of the view lock and the ccw device lock. raw3270_activate_view/raw3270_deactivate_view first take the ccw device lock then call the activate/deactivate functions of the view which take view lock. The update functions of the con3270/tty3270 view will first take the view lock, then take the ccw device lock. To fix this the activate/deactivate functions are changed to avoid taking the view lock by moving the functions calls that modify the 3270 output buffer to the update function which is called by a timer. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/char/tty3270.c')
-rw-r--r--drivers/s390/char/tty3270.c42
1 files changed, 18 insertions, 24 deletions
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index aa7a114f652..38385677c65 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -112,7 +112,7 @@ struct tty3270 {
#define TTY_UPDATE_LIST 2 /* Update lines in tty3270->update. */
#define TTY_UPDATE_INPUT 4 /* Update input line. */
#define TTY_UPDATE_STATUS 8 /* Update status line. */
-#define TTY_UPDATE_ALL 15
+#define TTY_UPDATE_ALL 16 /* Recreate screen. */
static void tty3270_update(struct tty3270 *);
@@ -121,19 +121,10 @@ static void tty3270_update(struct tty3270 *);
*/
static void tty3270_set_timer(struct tty3270 *tp, int expires)
{
- if (expires == 0) {
- if (timer_pending(&tp->timer) && del_timer(&tp->timer))
- raw3270_put_view(&tp->view);
- return;
- }
- if (timer_pending(&tp->timer) &&
- mod_timer(&tp->timer, jiffies + expires))
- return;
- raw3270_get_view(&tp->view);
- tp->timer.function = (void (*)(unsigned long)) tty3270_update;
- tp->timer.data = (unsigned long) tp;
- tp->timer.expires = jiffies + expires;
- add_timer(&tp->timer);
+ if (expires == 0)
+ del_timer(&tp->timer);
+ else
+ mod_timer(&tp->timer, jiffies + expires);
}
/*
@@ -337,7 +328,6 @@ tty3270_write_callback(struct raw3270_request *rq, void *data)
tp = (struct tty3270 *) rq->view;
if (rq->rc != 0) {
/* Write wasn't successfull. Refresh all. */
- tty3270_rebuild_update(tp);
tp->update_flags = TTY_UPDATE_ALL;
tty3270_set_timer(tp, 1);
}
@@ -366,6 +356,12 @@ tty3270_update(struct tty3270 *tp)
spin_lock(&tp->view.lock);
updated = 0;
+ if (tp->update_flags & TTY_UPDATE_ALL) {
+ tty3270_rebuild_update(tp);
+ tty3270_update_status(tp);
+ tp->update_flags = TTY_UPDATE_ERASE | TTY_UPDATE_LIST |
+ TTY_UPDATE_INPUT | TTY_UPDATE_STATUS;
+ }
if (tp->update_flags & TTY_UPDATE_ERASE) {
/* Use erase write alternate to erase display. */
raw3270_request_set_cmd(wrq, TC_EWRITEA);
@@ -425,7 +421,6 @@ tty3270_update(struct tty3270 *tp)
xchg(&tp->write, wrq);
}
spin_unlock(&tp->view.lock);
- raw3270_put_view(&tp->view);
}
/*
@@ -570,7 +565,6 @@ tty3270_read_tasklet(struct raw3270_request *rrq)
tty3270_set_timer(tp, 1);
} else if (tp->input->string[0] == 0x6d) {
/* Display has been cleared. Redraw. */
- tty3270_rebuild_update(tp);
tp->update_flags = TTY_UPDATE_ALL;
tty3270_set_timer(tp, 1);
}
@@ -641,22 +635,20 @@ static int
tty3270_activate(struct raw3270_view *view)
{
struct tty3270 *tp;
- unsigned long flags;
tp = (struct tty3270 *) view;
- spin_lock_irqsave(&tp->view.lock, flags);
- tp->nr_up = 0;
- tty3270_rebuild_update(tp);
- tty3270_update_status(tp);
tp->update_flags = TTY_UPDATE_ALL;
tty3270_set_timer(tp, 1);
- spin_unlock_irqrestore(&tp->view.lock, flags);
return 0;
}
static void
tty3270_deactivate(struct raw3270_view *view)
{
+ struct tty3270 *tp;
+
+ tp = (struct tty3270 *) view;
+ del_timer(&tp->timer);
}
static int
@@ -743,6 +735,7 @@ tty3270_free_view(struct tty3270 *tp)
{
int pages;
+ del_timer_sync(&tp->timer);
kbd_free(tp->kbd);
raw3270_request_free(tp->kreset);
raw3270_request_free(tp->read);
@@ -889,7 +882,8 @@ tty3270_open(struct tty_struct *tty, struct file * filp)
INIT_LIST_HEAD(&tp->update);
INIT_LIST_HEAD(&tp->rcl_lines);
tp->rcl_max = 20;
- init_timer(&tp->timer);
+ setup_timer(&tp->timer, (void (*)(unsigned long)) tty3270_update,
+ (unsigned long) tp);
tasklet_init(&tp->readlet,
(void (*)(unsigned long)) tty3270_read_tasklet,
(unsigned long) tp->read);