net: introduce napi_is_scheduled helper

We currently have napi_if_scheduled_mark_missed that can be used to
check if napi is scheduled but that does more thing than simply checking
it and return a bool. Some driver already implement custom function to
check if napi is scheduled.

Drop these custom function and introduce napi_is_scheduled that simply
check if napi is scheduled atomically.

Update any driver and code that implement a similar check and instead
use this new helper.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1c7681263d3026..b8bf669212cce0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -482,6 +482,29 @@ static inline bool napi_prefer_busy_poll(struct napi_struct *n)
 	return test_bit(NAPI_STATE_PREFER_BUSY_POLL, &n->state);
 }
 
+/**
+ * napi_is_scheduled - test if NAPI is scheduled
+ * @n: NAPI context
+ *
+ * This check is "best-effort". With no locking implemented,
+ * a NAPI can be scheduled or terminate right after this check
+ * and produce not precise results.
+ *
+ * NAPI_STATE_SCHED is an internal state, napi_is_scheduled
+ * should not be used normally and napi_schedule should be
+ * used instead.
+ *
+ * Use only if the driver really needs to check if a NAPI
+ * is scheduled for example in the context of delayed timer
+ * that can be skipped if a NAPI is already scheduled.
+ *
+ * Return True if NAPI is scheduled, False otherwise.
+ */
+static inline bool napi_is_scheduled(struct napi_struct *n)
+{
+	return test_bit(NAPI_STATE_SCHED, &n->state);
+}
+
 bool napi_schedule_prep(struct napi_struct *n);
 
 /**