[RFT 3/9] Char: moxa, serialise timer

From: Jiri Slaby
Date: Thu Feb 07 2008 - 14:13:11 EST


- del timer after we are sure it won't be fired again
- make timer scheduling atomic
- don't reschedule timer when all cards have gone

Signed-off-by: Jiri Slaby <jirislaby@xxxxxxxxx>
---
drivers/char/moxa.c | 26 +++++++++++++++-----------
1 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index f45405f..eabb2e0 100644
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -846,10 +846,11 @@ static int moxa_init_board(struct moxa_board_conf *brd, struct device *dev)
if (ret)
goto err_free;

+ spin_lock_bh(&moxa_lock);
brd->ready = 1;
-
if (!timer_pending(&moxaTimer))
mod_timer(&moxaTimer, jiffies + HZ / 50);
+ spin_unlock_bh(&moxa_lock);

return 0;
err_free:
@@ -1040,13 +1041,6 @@ static void __exit moxa_exit(void)
{
int i;

- del_timer_sync(&moxaTimer);
-
- if (tty_unregister_driver(moxaDriver))
- printk(KERN_ERR "Couldn't unregister MOXA Intellio family "
- "serial driver\n");
- put_tty_driver(moxaDriver);
-
#ifdef CONFIG_PCI
pci_unregister_driver(&moxa_pci_driver);
#endif
@@ -1054,6 +1048,13 @@ static void __exit moxa_exit(void)
for (i = 0; i < MAX_BOARDS; i++) /* ISA boards */
if (moxa_boards[i].ready)
moxa_board_deinit(&moxa_boards[i]);
+
+ del_timer_sync(&moxaTimer);
+
+ if (tty_unregister_driver(moxaDriver))
+ printk(KERN_ERR "Couldn't unregister MOXA Intellio family "
+ "serial driver\n");
+ put_tty_driver(moxaDriver);
}

module_init(moxa_init);
@@ -1432,7 +1433,7 @@ static void moxa_poll(unsigned long ignored)
{
struct moxa_board_conf *brd;
u16 __iomem *ip;
- unsigned int card, port;
+ unsigned int card, port, served = 0;

spin_lock(&moxa_lock);
for (card = 0; card < MAX_BOARDS; card++) {
@@ -1440,6 +1441,8 @@ static void moxa_poll(unsigned long ignored)
if (!brd->ready)
continue;

+ served++;
+
ip = NULL;
if (readb(brd->intPend) == 0xff)
ip = brd->intTable + readb(brd->intNdx);
@@ -1460,9 +1463,10 @@ static void moxa_poll(unsigned long ignored)
}
}
moxaLowWaterChk = 0;
- spin_unlock(&moxa_lock);

- mod_timer(&moxaTimer, jiffies + HZ / 50);
+ if (served)
+ mod_timer(&moxaTimer, jiffies + HZ / 50);
+ spin_unlock(&moxa_lock);
}

/******************************************************************************/
--
1.5.3.8

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