[PATCH v3 1/4] i915: Move list_count() to list.h for broader use

Andy Shevchenko
2022-11-22T15:35:31Z

Some of the existing users, and definitely will be new ones, want to
count existing nodes in the list. Provide a generic API for that by
moving code from i915 to list.h.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
---
v3: added tag (Jani), changed to be static inline (Mike)
v2: dropped the duplicate code in i915 (LKP)
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 13 +------------
include/linux/list.h | 15 +++++++++++++++
2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 6ae8b07cfaa1..b5d474be564d 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -2085,17 +2085,6 @@ static void print_request_ring(struct drm_printer *m, struct i915_request *rq)
}
}

-static unsigned long list_count(struct list_head *list)
-{
- struct list_head *pos;
- unsigned long count = 0;
-
- list_for_each(pos, list)
- count++;
-
- return count;
-}
-
static unsigned long read_ul(void *p, size_t x)
{
return *(unsigned long *)(p + x);
@@ -2270,7 +2259,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
spin_lock_irqsave(&engine->sched_engine->lock, flags);
engine_dump_active_requests(engine, m);

- drm_printf(m, "\tOn hold?: %lu\n",
+ drm_printf(m, "\tOn hold?: %zu\n",
list_count(&engine->sched_engine->hold));
spin_unlock_irqrestore(&engine->sched_engine->lock, flags);

diff --git a/include/linux/list.h b/include/linux/list.h
index 61762054b4be..65aab596ae33 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -655,6 +655,21 @@ static inline void list_splice_tail_init(struct list_head *list,
!list_is_head(pos, (head)); \
pos = n, n = pos->prev)

+/**
+ * list_count - count nodes in the list
+ * @head: the head for your list.
+ */
+size_t list_count(struct list_head *head)
+{
+ struct list_head *pos;
+ size_t count = 0;
+
+ list_for_each(pos, head)
+ count++;
+
+ return count;
+}
+
/**
* list_entry_is_head - test if the entry points to the head of the list
* @pos: the type * to cursor
--
2.35.1