From fb75d109a1a264946b8fba01331bc557a8994820 Mon Sep 17 00:00:00 2001
From: Neels Hofmeyr <neels@hofmeyr.de>
Date: Fri, 18 May 2018 03:46:41 +0200
Subject: cosmetic: penalty timers: constify, tweak doc

Change-Id: I28addc9a16a4c81978290303d368f630a8334228
---
 include/osmocom/bsc/penalty_timers.h | 17 +++++++++++------
 src/osmo-bsc/penalty_timers.c        |  8 ++++----
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/osmocom/bsc/penalty_timers.h b/include/osmocom/bsc/penalty_timers.h
index 4b1dcce55..3aae8a0e5 100644
--- a/include/osmocom/bsc/penalty_timers.h
+++ b/include/osmocom/bsc/penalty_timers.h
@@ -10,24 +10,29 @@ struct penalty_timers;
  * returns an empty struct penalty_timers.  */
 struct penalty_timers *penalty_timers_init(void *ctx);
 
-/* Add a penalty timer for a BTS.
+/* Add a penalty timer for an arbitary object.
+ * Note: the ownership of for_object remains with the caller; it is handled as a mere void* value, so
+ * invalid pointers can be handled without problems, while common sense dictates that invalidated
+ * pointers (freed objects) should probably be removed from this list. More importantly, the pointer must
+ * match any pointers used to query penalty timers, so for_object should reference some global/singleton
+ * object that tends to stay around longer than the penalty timers.
  * param pt: penalty timers list as from penalty_timers_init().
  * param for_object: arbitrary pointer reference to store a penalty timer for (passing NULL is possible,
  *         but note that penalty_timers_clear() will clear all timers if given for_object=NULL).
  * param timeout: penalty time in seconds. */
-void penalty_timers_add(struct penalty_timers *pt, void *for_object, int timeout);
+void penalty_timers_add(struct penalty_timers *pt, const void *for_object, int timeout);
 
-/* Return the amount of penalty time remaining for a BTS.
+/* Return the amount of penalty time remaining for an object.
  * param pt: penalty timers list as from penalty_timers_init().
  * param for_object: arbitrary pointer reference to query penalty timers for.
  * returns seconds remaining until all penalty time has expired. */
-unsigned int penalty_timers_remaining(struct penalty_timers *pt, void *for_object);
+unsigned int penalty_timers_remaining(struct penalty_timers *pt, const void *for_object);
 
-/* Clear penalty timers for one or all BTS.
+/* Clear penalty timers for one or all objects.
  * param pt: penalty timers list as from penalty_timers_init().
  * param for_object: arbitrary pointer reference to clear penalty time for,
  *                   or NULL to clear all timers. */
-void penalty_timers_clear(struct penalty_timers *pt, void *for_object);
+void penalty_timers_clear(struct penalty_timers *pt, const void *for_object);
 
 /* Free a struct as returned from penalty_timers_init().
  * Clear all timers from the list, deallocate the list and set the pointer to NULL.
diff --git a/src/osmo-bsc/penalty_timers.c b/src/osmo-bsc/penalty_timers.c
index b80fec946..02cf2468a 100644
--- a/src/osmo-bsc/penalty_timers.c
+++ b/src/osmo-bsc/penalty_timers.c
@@ -34,7 +34,7 @@ struct penalty_timers {
 
 struct penalty_timer {
 	struct llist_head entry;
-	void *for_object;
+	const void *for_object;
 	unsigned int timeout;
 };
 
@@ -55,7 +55,7 @@ struct penalty_timers *penalty_timers_init(void *ctx)
 	return pt;
 }
 
-void penalty_timers_add(struct penalty_timers *pt, void *for_object, int timeout)
+void penalty_timers_add(struct penalty_timers *pt, const void *for_object, int timeout)
 {
 	struct penalty_timer *timer;
 	unsigned int now;
@@ -89,7 +89,7 @@ void penalty_timers_add(struct penalty_timers *pt, void *for_object, int timeout
 	llist_add_tail(&timer->entry, &pt->timers);
 }
 
-unsigned int penalty_timers_remaining(struct penalty_timers *pt, void *for_object)
+unsigned int penalty_timers_remaining(struct penalty_timers *pt, const void *for_object)
 {
 	struct penalty_timer *timer;
 	unsigned int now = time_now();
@@ -107,7 +107,7 @@ unsigned int penalty_timers_remaining(struct penalty_timers *pt, void *for_objec
 	return max_remaining;
 }
 
-void penalty_timers_clear(struct penalty_timers *pt, void *for_object)
+void penalty_timers_clear(struct penalty_timers *pt, const void *for_object)
 {
 	struct penalty_timer *timer, *timer2;
 	llist_for_each_entry_safe(timer, timer2, &pt->timers, entry) {
-- 
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