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In reponse to a report of a blocking violation, give sync queues a going over and catch any old, obscure leftover issues. A couple spots needed interrupt stopage where there could be confict if an IRQ post wakes a waiting thread because the queue is overflowing. There does appear to be an issue with wakeup_thread, interrupts and running list modification in general.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12895 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2007-03-23 01:00:13 +00:00
parent 8b40769554
commit 6d87513aa2
1 changed files with 26 additions and 4 deletions
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30
firmware/kernel.c
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@ -100,6 +100,7 @@ void yield(void)
static void queue_fetch_sender(struct queue_sender_list *send, static void queue_fetch_sender(struct queue_sender_list *send,
unsigned int i) unsigned int i)
{ {
/* Disable interrupts to protect against collision in this slot */
int old_level = set_irq_level(HIGHEST_IRQ_LEVEL); int old_level = set_irq_level(HIGHEST_IRQ_LEVEL);
struct thread_entry **spp = &send->senders[i]; struct thread_entry **spp = &send->senders[i];
@ -113,17 +114,31 @@ static void queue_fetch_sender(struct queue_sender_list *send,
} }
/* Puts the specified return value in the waiting thread's return value /* Puts the specified return value in the waiting thread's return value
and wakes the thread - a sender should be confirmed to exist first */ * and wakes the thread.
* 1) A sender should be confirmed to exist before calling which makes it
* more efficent to reject the majority of cases that don't need this
called.
* 2) Requires interrupts disabled since queue overflows can cause posts
* from interrupt handlers to wake threads. Not doing so could cause
* an attempt at multiple wakes or other problems.
*/
static void queue_release_sender(struct thread_entry **sender, static void queue_release_sender(struct thread_entry **sender,
intptr_t retval) intptr_t retval)
{ {
(*sender)->retval = retval; (*sender)->retval = retval;
wakeup_thread(sender); wakeup_thread(sender);
*sender = NULL; #if 0
/* This should _never_ happen - there must never be multiple
threads in this list and it is a corrupt state */
if (*sender != NULL)
panicf("Queue: send slot ovf");
#endif
} }
/* Releases any waiting threads that are queued with queue_send - /* Releases any waiting threads that are queued with queue_send -
reply with NULL */ * reply with 0.
* Disable IRQs before calling since it uses queue_release_sender.
*/
static void queue_release_all_senders(struct event_queue *q) static void queue_release_all_senders(struct event_queue *q)
{ {
if(q->send) if(q->send)
@ -191,8 +206,10 @@ void queue_delete(struct event_queue *q)
#ifdef HAVE_EXTENDED_MESSAGING_AND_NAME #ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
/* Release waiting threads and reply to any dequeued message /* Release waiting threads and reply to any dequeued message
waiting for one. */ waiting for one. */
int level = set_irq_level(HIGHEST_IRQ_LEVEL);
queue_release_all_senders(q); queue_release_all_senders(q);
queue_reply(q, NULL); queue_reply(q, NULL);
set_irq_level(level);
#endif #endif
/* Move the following queues up in the list */ /* Move the following queues up in the list */
for(;i < num_queues-1;i++) for(;i < num_queues-1;i++)
@ -319,7 +336,12 @@ void queue_reply(struct event_queue *q, intptr_t retval)
{ {
if(q->send && q->send->curr_sender) if(q->send && q->send->curr_sender)
{ {
queue_release_sender(&q->send->curr_sender, retval); int level = set_irq_level(HIGHEST_IRQ_LEVEL);
if(q->send->curr_sender)
{
queue_release_sender(&q->send->curr_sender, retval);
}
set_irq_level(level);
} }
} }
#endif /* HAVE_EXTENDED_MESSAGING_AND_NAME */ #endif /* HAVE_EXTENDED_MESSAGING_AND_NAME */