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[retry] Use a separate flag to indicate that a retry timer is running
Using start==0 to indicate a stopped timer is dangerous, because 0 is a
valid value for the current tick counter.
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Michael Brown committed Oct 12, 2008
1 parent 941b4c2 commit f945d6d
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Showing 2 changed files with 12 additions and 9 deletions.
9 changes: 4 additions & 5 deletions src/include/gpxe/retry.h
Expand Up @@ -19,6 +19,8 @@
struct retry_timer {
/** List of active timers */
struct list_head list;
/** Timer is currently running */
unsigned int running;
/** Timeout value (in ticks) */
unsigned long timeout;
/** Minimum timeout value (in ticks)
Expand All @@ -31,10 +33,7 @@ struct retry_timer {
* A value of zero means "use default timeout."
*/
unsigned long max_timeout;
/** Start time (in ticks)
*
* A start time of zero indicates a stopped timer.
*/
/** Start time (in ticks) */
unsigned long start;
/** Retry count */
unsigned int count;
Expand Down Expand Up @@ -74,7 +73,7 @@ static inline void start_timer_nodelay ( struct retry_timer *timer ) {
*/
static inline __attribute__ (( always_inline )) unsigned long
timer_running ( struct retry_timer *timer ) {
return ( timer->start );
return ( timer->running );
}

#endif /* _GPXE_RETRY_H */
12 changes: 8 additions & 4 deletions src/net/retry.c
Expand Up @@ -55,9 +55,10 @@ static LIST_HEAD ( timers );
* be stopped and the timer's callback function will be called.
*/
void start_timer ( struct retry_timer *timer ) {
if ( ! timer_running ( timer ) )
if ( ! timer->running )
list_add ( &timer->list, &timers );
timer->start = currticks();
timer->running = 1;

/* 0 means "use default timeout" */
if ( timer->min_timeout == 0 )
Expand All @@ -82,6 +83,8 @@ void start_timer ( struct retry_timer *timer ) {
void start_timer_fixed ( struct retry_timer *timer, unsigned long timeout ) {
start_timer ( timer );
timer->timeout = timeout;
DBG2 ( "Timer %p expiry time changed to %ld\n",
timer, ( timer->start + timer->timeout ) );
}

/**
Expand All @@ -97,12 +100,12 @@ void stop_timer ( struct retry_timer *timer ) {
unsigned long runtime;

/* If timer was already stopped, do nothing */
if ( ! timer_running ( timer ) )
if ( ! timer->running )
return;

list_del ( &timer->list );
runtime = ( now - timer->start );
timer->start = 0;
timer->running = 0;
DBG2 ( "Timer %p stopped at time %ld (ran for %ld)\n",
timer, now, runtime );

Expand Down Expand Up @@ -144,8 +147,9 @@ static void timer_expired ( struct retry_timer *timer ) {
/* Stop timer without performing RTT calculations */
DBG2 ( "Timer %p stopped at time %ld on expiry\n",
timer, currticks() );
assert ( timer->running );
list_del ( &timer->list );
timer->start = 0;
timer->running = 0;
timer->count++;

/* Back off the timeout value */
Expand Down

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