list: add hlist_count_nodes()

Add a generic hlist_count_nodes() function and use it in two drivers.


This patch (of 3):

Add a function to count nodes in a hlist.  hlist_count_nodes() is similar
to list_count_nodes().

Link: https://lkml.kernel.org/r/20240104164937.424320-1-pierre.gondois@arm.com
Link: https://lkml.kernel.org/r/20240104164937.424320-2-pierre.gondois@arm.comSigned-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Acked-by: Coly Li <colyli@suse.de>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Martijn Coenen <maco@android.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Todd Kjos <tkjos@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/list.h

@@ -1195,4 +1195,19 @@ static inline void hlist_splice_init(struct hlist_head *from,
 	     pos && ({ n = pos->member.next; 1; });			\
 	     pos = hlist_entry_safe(n, typeof(*pos), member))
 
+/**
+ * hlist_count_nodes - count nodes in the hlist
+ * @head:	the head for your hlist.
+ */
+static inline size_t hlist_count_nodes(struct hlist_head *head)
+{
+	struct hlist_node *pos;
+	size_t count = 0;
+
+	hlist_for_each(pos, head)
+		count++;
+
+	return count;
+}
+
 #endif