[patch 34/40] Char: moxa, fix and optimise empty timer

[Greg Kroah-Hartman <gregkh@suse.de>]

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-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Jiri Slaby <jirislaby@gmail.com>

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>

---
 drivers/char/moxa.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -1040,14 +1040,14 @@ static void check_xmit_empty(unsigned lo
 	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;
 }

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