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ip2: avoid add_timer with pending timer

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add_timer() is not supposed to be called when the timer is pending.
ip2 driver attempts to avoid that condition by setting and resetting
a flag (TimerOn) in timer function. But there is some gap between
add_timer() and setting TimerOn.

This patch fix this problem by using mod_timer() and remove TimerOn
which has been unnecessary by this change.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2008-10-13 10:35:05 +01:00 committed by Linus Torvalds
parent f1ddfd9502
commit 9d020a2e5f
1 changed files with 4 additions and 15 deletions
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19
drivers/char/ip2/ip2main.c
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@ -249,7 +249,6 @@ static unsigned long bh_counter;
*/ */
#define POLL_TIMEOUT (jiffies + 1) #define POLL_TIMEOUT (jiffies + 1)
static DEFINE_TIMER(PollTimer, ip2_poll, 0, 0); static DEFINE_TIMER(PollTimer, ip2_poll, 0, 0);
static char TimerOn;
#ifdef IP2DEBUG_TRACE #ifdef IP2DEBUG_TRACE
/* Trace (debug) buffer data */ /* Trace (debug) buffer data */
@ -374,11 +373,7 @@ static void __exit ip2_cleanup_module(void)
int err; int err;
int i; int i;
/* Stop poll timer if we had one. */ del_timer_sync(&PollTimer);
if (TimerOn) {
del_timer(&PollTimer);
TimerOn = 0;
}
/* Reset the boards we have. */ /* Reset the boards we have. */
for (i = 0; i < IP2_MAX_BOARDS; i++) for (i = 0; i < IP2_MAX_BOARDS; i++)
@ -774,10 +769,8 @@ static int __init ip2_loadmain(void)
} }
if (ip2config.irq[i] == CIR_POLL) { if (ip2config.irq[i] == CIR_POLL) {
retry: retry:
if (!TimerOn) { if (!timer_pending(&PollTimer)) {
PollTimer.expires = POLL_TIMEOUT; mod_timer(&PollTimer, POLL_TIMEOUT);
add_timer(&PollTimer);
TimerOn = 1;
printk(KERN_INFO "IP2: polling\n"); printk(KERN_INFO "IP2: polling\n");
} }
} else { } else {
@ -1283,16 +1276,12 @@ ip2_poll(unsigned long arg)
{ {
ip2trace (ITRC_NO_PORT, ITRC_INTR, 100, 0 ); ip2trace (ITRC_NO_PORT, ITRC_INTR, 100, 0 );
TimerOn = 0; // it's the truth but not checked in service
// Just polled boards, IRQ = 0 will hit all non-interrupt boards. // Just polled boards, IRQ = 0 will hit all non-interrupt boards.
// It will NOT poll boards handled by hard interrupts. // It will NOT poll boards handled by hard interrupts.
// The issue of queued BH interrupts is handled in ip2_interrupt(). // The issue of queued BH interrupts is handled in ip2_interrupt().
ip2_polled_interrupt(); ip2_polled_interrupt();
PollTimer.expires = POLL_TIMEOUT; mod_timer(&PollTimer, POLL_TIMEOUT);
add_timer( &PollTimer );
TimerOn = 1;
ip2trace (ITRC_NO_PORT, ITRC_INTR, ITRC_RETURN, 0 ); ip2trace (ITRC_NO_PORT, ITRC_INTR, ITRC_RETURN, 0 );
} }