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Commit 9d020a2e authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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ip2: avoid add_timer with pending timer 



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: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarJiri Slaby <jirislaby@gmail.com>
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f1ddfd95

drivers/char/ip2/ip2main.c

+4 −15
Original line number Original line Diff line number Diff line
@@ -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 );

}

}