Char: moxa, fix and optimise empty timer

patch c43422053bea7a5ce09f18d0c50a606fe1a549f4 in mainline.

moxa, fix and optimise empty timer

don't wait and delete empty timer in empty timer function. Also fire next
empty timer at rounded jiffies to save power.

This fixes a lockup, because we wait for ourselves to finish forever.
(i.e.  sync called from the timer itself).

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index ed76f0a127fd759c1679a908681c25fcdfc15064..5000b3bd091eff0d022526f13d472376e693941d 100644 (file)
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -1040,14 +1040,14 @@ static void check_xmit_empty(unsigned long data)
        struct moxa_port *ch;
 
        ch = (struct moxa_port *) data;
-       del_timer_sync(&moxa_ports[ch->port].emptyTimer);
        if (ch->tty && (ch->statusflags & EMPTYWAIT)) {
                if (MoxaPortTxQueue(ch->port) == 0) {
                        ch->statusflags &= ~EMPTYWAIT;
                        tty_wakeup(ch->tty);
                        return;
                }
-               mod_timer(&moxa_ports[ch->port].emptyTimer, jiffies + HZ);
+               mod_timer(&moxa_ports[ch->port].emptyTimer,
+                               round_jiffies(jiffies + HZ));
        } else
                ch->statusflags &= ~EMPTYWAIT;
 }