[PATCH bpf-next 1/3] net: Add napi_init_for_gro utility routine

[Lorenzo Bianconi <lorenzo@xxxxxxxxxx>]

Introduce napi_init_for_gro utility routine to initialize napi struct
subfields not dependent by net_device pointer.
This is a preliminary patch to enable GRO support to cpumap codebase
without introducing net_device dependency in the cpumap_entry struct.

Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
 include/linux/netdevice.h |  2 ++
 net/core/dev.c            | 17 ++++++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ecc686409161ea8684926434a9dcb233e065dd6c..9f083314fc4bc97059b02c6ee6d919bedb4e046d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2677,6 +2677,8 @@ static inline void netif_napi_set_irq(struct napi_struct *napi, int irq)
  */
 #define NAPI_POLL_WEIGHT 64
 
+int napi_init_for_gro(struct net_device *dev, struct napi_struct *napi,
+		      int (*poll)(struct napi_struct *, int), int weight);
 void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
 			   int (*poll)(struct napi_struct *, int), int weight);
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 13d00fc10f55998077cb643a2f6e3c171974589d..20d531a54214e9ecf1128a668cf3763433e1989b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6723,13 +6723,14 @@ static void napi_save_config(struct napi_struct *n)
 	napi_hash_del(n);
 }
 
-void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
-			   int (*poll)(struct napi_struct *, int), int weight)
+int napi_init_for_gro(struct net_device *dev, struct napi_struct *napi,
+		      int (*poll)(struct napi_struct *, int), int weight)
 {
 	if (WARN_ON(test_and_set_bit(NAPI_STATE_LISTED, &napi->state)))
-		return;
+		return -EBUSY;
 
 	INIT_LIST_HEAD(&napi->poll_list);
+	INIT_LIST_HEAD(&napi->dev_list);
 	INIT_HLIST_NODE(&napi->napi_hash_node);
 	hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
 	napi->timer.function = napi_watchdog;
@@ -6747,6 +6748,16 @@ void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
 	napi->poll_owner = -1;
 #endif
 	napi->list_owner = -1;
+
+	return 0;
+}
+
+void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi,
+			   int (*poll)(struct napi_struct *, int), int weight)
+{
+	if (napi_init_for_gro(dev, napi, poll, weight))
+		return;
+
 	set_bit(NAPI_STATE_SCHED, &napi->state);
 	set_bit(NAPI_STATE_NPSVC, &napi->state);
 	list_add_rcu(&napi->dev_list, &dev->napi_list);

-- 
2.47.0