netdev - [PATCH net-next v5 10/12] net: add option to request netdev instance lock

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Message-ID: <20250219202719.957100-11-sdf@fomichev.me>
Date: Wed, 19 Feb 2025 12:27:17 -0800
From: Stanislav Fomichev <sdf@...ichev.me>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	Saeed Mahameed <saeed@...nel.org>
Subject: [PATCH net-next v5 10/12] net: add option to request netdev instance lock

Currently only the drivers that implement shaper or queue APIs
are grabbing instance lock. Add an explicit opt-in for the
drivers that want to grab the lock without implementing the above
APIs.

There is a 3-byte hole after @up, use it:

        /* --- cacheline 47 boundary (3008 bytes) --- */
        u32                        napi_defer_hard_irqs; /*  3008     4 */
        bool                       up;                   /*  3012     1 */

        /* XXX 3 bytes hole, try to pack */

        struct mutex               lock;                 /*  3016   144 */

        /* XXX last struct has 1 hole */

Cc: Saeed Mahameed <saeed@...nel.org>
Signed-off-by: Stanislav Fomichev <sdf@...ichev.me>
---
 include/linux/netdevice.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index eb44b2ecc076..4a11e78b1a60 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2456,6 +2456,12 @@ struct net_device {
 	 */
 	bool			up;
 
+	/**
+	 * @request_ops_lock: request the core to run all @netdev_ops and
+	 * @ethtool_ops under the @lock.
+	 */
+	bool			request_ops_lock;
+
 	/**
 	 * @lock: netdev-scope lock, protects a small selection of fields.
 	 * Should always be taken using netdev_lock() / netdev_unlock() helpers.
@@ -2743,7 +2749,7 @@ static inline void netdev_assert_locked_or_invisible(struct net_device *dev)
 
 static inline bool netdev_need_ops_lock(struct net_device *dev)
 {
-	bool ret = !!dev->queue_mgmt_ops;
+	bool ret = dev->request_ops_lock || !!dev->queue_mgmt_ops;
 
 #if IS_ENABLED(CONFIG_NET_SHAPER)
 	ret |= !!dev->netdev_ops->net_shaper_ops;
-- 
2.48.1