linuxlist.h: add llist_count()
After subchan_demux.c in libosmo-abis, osmo-bts/common/vty.c and openbsc's
gtphub_test.c, more places would like to count the llist items (mostly unit
tests). Instead of proliferating numerous local implementations, add here.
NOTE: other than the previous llist_len() implementations, this one returns an
*unsigned* length, which might need some adjusting of current callers.
Call this llist_count() rather than llist_len() to highlight the fact that this
is actively iterating. This also avoids a potential naming conflict when
library versions mismatch.
Change-Id: Ic49adc7a346f5722bf624d7d3b4a735e4220ae15
diff --git a/include/osmocom/core/linuxlist.h b/include/osmocom/core/linuxlist.h
index 1c83395..affa827 100644
--- a/include/osmocom/core/linuxlist.h
+++ b/include/osmocom/core/linuxlist.h
@@ -351,6 +351,22 @@
for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \
(pos) = (pos)->next, ({ smp_read_barrier_depends(); 0;}), prefetch((pos)->next))
+/*! \brief count nr of llist items by iterating.
+ * \param head The llist head to count items of.
+ * \returns Number of items.
+ *
+ * This function is not efficient, mostly useful for small lists and non time
+ * critical cases like unit tests.
+ */
+static inline unsigned int llist_count(struct llist_head *head)
+{
+ struct llist_head *entry;
+ unsigned int i = 0;
+ llist_for_each(entry, head)
+ i++;
+ return i;
+}
+
/*!
* }@
*/