Thread (30 messages) 30 messages, 9 authors, 2020-09-30
STALE2071d

[RFC PATCH net-next 3/6] net: extract napi poll functionality to __napi_poll()

From: Wei Wang <hidden>
Date: 2020-09-14 17:27:31
Subsystem: networking [general], the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

From: Felix Fietkau <nbd@nbd.name> 

This commit introduces a new function __napi_poll() which does the main
logic of the existing napi_poll() function, and will be called by other
functions in later commits.
This idea and implementation is done by Felix Fietkau [off-list ref] and
is proposed as part of the patch to move napi work to work_queue
context.
This commit by itself is a code restructure.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Wei Wang <redacted>
---
 net/core/dev.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 0fe4c531b682..bc2a7681b239 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6719,15 +6719,10 @@ void __netif_napi_del(struct napi_struct *napi)
 }
 EXPORT_SYMBOL(__netif_napi_del);
 
-static int napi_poll(struct napi_struct *n, struct list_head *repoll)
+static int __napi_poll(struct napi_struct *n, bool *repoll)
 {
-	void *have;
 	int work, weight;
 
-	list_del_init(&n->poll_list);
-
-	have = netpoll_poll_lock(n);
-
 	weight = n->weight;
 
 	/* This NAPI_STATE_SCHED test is for avoiding a race
@@ -6747,7 +6742,7 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
 			    n->poll, work, weight);
 
 	if (likely(work < weight))
-		goto out_unlock;
+		return work;
 
 	/* Drivers must not modify the NAPI state if they
 	 * consume the entire weight.  In such cases this code
@@ -6756,7 +6751,7 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
 	 */
 	if (unlikely(napi_disable_pending(n))) {
 		napi_complete(n);
-		goto out_unlock;
+		return work;
 	}
 
 	if (n->gro_bitmask) {
@@ -6768,6 +6763,26 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
 
 	gro_normal_list(n);
 
+	*repoll = true;
+
+	return work;
+}
+
+static int napi_poll(struct napi_struct *n, struct list_head *repoll)
+{
+	bool do_repoll = false;
+	void *have;
+	int work;
+
+	list_del_init(&n->poll_list);
+
+	have = netpoll_poll_lock(n);
+
+	work = __napi_poll(n, &do_repoll);
+
+	if (!do_repoll)
+		goto out_unlock;
+
 	/* Some drivers may have called napi_schedule
 	 * prior to exhausting their budget.
 	 */
-- 
2.28.0.618.gf4bc123cb7-goog
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