netdev - [PATCH net 1/2] net: add napi_schedule_prep variant with more granular return value

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Message-ID: <d739aa6d-f1e0-45fa-aad8-b4a1da779b30@gmail.com>
Date: Tue, 14 May 2024 08:50:37 +0200
From: Heiner Kallweit <hkallweit1@...il.com>
To: Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
 Eric Dumazet <edumazet@...gle.com>, David Miller <davem@...emloft.net>,
 Realtek linux nic maintainers <nic_swsd@...ltek.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
 Ken Milmore <ken.milmore@...il.com>
Subject: [PATCH net 1/2] net: add napi_schedule_prep variant with more
 granular return value

For deciding whether to disable device interrupts, drivers may need the
information whether NAPIF_STATE_DISABLE or NAPIF_STATE_SCHED was set.
Therefore add a __napi_schedule_prep() which returns -1 in case
NAPIF_STATE_DISABLE was set.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 include/linux/netdevice.h |  7 ++++++-
 net/core/dev.c            | 12 ++++++------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index cf261fb89..d1515cf8c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -498,7 +498,12 @@ 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);
+int __napi_schedule_prep(struct napi_struct *n);
+
+static inline bool napi_schedule_prep(struct napi_struct *n)
+{
+	return __napi_schedule_prep(n) > 0;
+}
 
 /**
  *	napi_schedule - schedule NAPI poll
diff --git a/net/core/dev.c b/net/core/dev.c
index d2ce91a33..66f55fc50 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6116,21 +6116,21 @@ void __napi_schedule(struct napi_struct *n)
 EXPORT_SYMBOL(__napi_schedule);
 
 /**
- *	napi_schedule_prep - check if napi can be scheduled
+ *	__napi_schedule_prep - check if napi can be scheduled
  *	@n: napi context
  *
  * Test if NAPI routine is already running, and if not mark
  * it as running.  This is used as a condition variable to
- * insure only one NAPI poll instance runs.  We also make
- * sure there is no pending NAPI disable.
+ * insure only one NAPI poll instance runs. Return -1 if
+ * there is a pending NAPI disable.
  */
-bool napi_schedule_prep(struct napi_struct *n)
+int __napi_schedule_prep(struct napi_struct *n)
 {
 	unsigned long new, val = READ_ONCE(n->state);
 
 	do {
 		if (unlikely(val & NAPIF_STATE_DISABLE))
-			return false;
+			return -1;
 		new = val | NAPIF_STATE_SCHED;
 
 		/* Sets STATE_MISSED bit if STATE_SCHED was already set
@@ -6145,7 +6145,7 @@ bool napi_schedule_prep(struct napi_struct *n)
 
 	return !(val & NAPIF_STATE_SCHED);
 }
-EXPORT_SYMBOL(napi_schedule_prep);
+EXPORT_SYMBOL(__napi_schedule_prep);
 
 /**
  * __napi_schedule_irqoff - schedule for receive
-- 
2.45.0