From cf78440ee6cb8c1469f53ca096d7388524facd59 Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Tue, 10 Dec 2013 15:09:36 +1100 Subject: drv_hrt: added note on why an uninitialised hrt_call is safe --- src/drivers/stm32/drv_hrt.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'src/drivers') diff --git a/src/drivers/stm32/drv_hrt.c b/src/drivers/stm32/drv_hrt.c index dc28f446b..1bd251bc2 100644 --- a/src/drivers/stm32/drv_hrt.c +++ b/src/drivers/stm32/drv_hrt.c @@ -720,7 +720,6 @@ hrt_call_at(struct hrt_call *entry, hrt_abstime calltime, hrt_callout callout, v void hrt_call_every(struct hrt_call *entry, hrt_abstime delay, hrt_abstime interval, hrt_callout callout, void *arg) { - hrt_call_init(entry); hrt_call_internal(entry, hrt_absolute_time() + delay, interval, @@ -734,6 +733,13 @@ hrt_call_internal(struct hrt_call *entry, hrt_abstime deadline, hrt_abstime inte irqstate_t flags = irqsave(); /* if the entry is currently queued, remove it */ + /* note that we are using a potentially uninitialised + entry->link here, but it is safe as sq_rem() doesn't + dereference the passed node unless it is found in the + list. So we potentially waste a bit of time searching the + queue for the uninitialised entry->link but we don't do + anything actually unsafe. + */ if (entry->deadline != 0) sq_rem(&entry->link, &callout_queue); -- cgit v1.2.3