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author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2009-06-12 10:26:31 +0200 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2009-06-12 10:27:33 +0200 |
commit | 205d7ab9c9af6847dda30650a0b8f98555a20654 (patch) | |
tree | b77071becdd91a01ba2b30b3bdd79388f738b96b /drivers/s390/char/tty3270.c | |
parent | fcf7581f7ca82e63e4e137be77c342a4e4ec8401 (diff) | |
download | linux-stable-205d7ab9c9af6847dda30650a0b8f98555a20654.tar.gz linux-stable-205d7ab9c9af6847dda30650a0b8f98555a20654.tar.bz2 linux-stable-205d7ab9c9af6847dda30650a0b8f98555a20654.zip |
[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.c | 42 |
1 files changed, 18 insertions, 24 deletions
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c index aa7a114f6529..38385677c653 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); |