[PATCH net-next 0/8] netpoll: move out netconsole-specific functions

[PATCH net-next 0/8] netpoll: move out netconsole-specific functions

[Breno Leitao]

netpoll and netconsole were created together and their code has
been intermixed in net/core/netpoll.c for decades. The result is
that netpoll exposes two send-side interfaces:

 * a generic "give me an sk_buff" path used by every stacked-device
   driver (bonding, team, vlan, bridge, macvlan, dsa),

 * a second path that takes raw bytes and builds a UDP/IP/Ethernet
   packet -- exclusively for netconsole.

The packet builder, an skb pool allocator, and several
netconsole-specific helpers all live next to the generic plumbing even
though no other consumer ever touches them.

Worse, every netpoll user pays for that overlap: struct netpoll carries
an skb_pool and a refill work_struct that only netconsole's find_skb()
ever reads from, and net-core has to review unrelated changes (TTL, hop
limit, IP ID generation, source MAC selection, pool sizing) just because
they happen to be coded inside netpoll.

This is a waste of memory for something useless.

This series splits the netconsole-specific code out:

 * netpoll_send_udp() and its private helpers (push_ipv6, push_ipv4,
push_eth, push_udp, netpoll_udp_checksum, find_skb) move into
drivers/net/netconsole.c, leaving netpoll with a single skb-only
send interface that is the same for every user.

The moves are one function per patch for reviewability; helpers are
temporarily EXPORT_SYMBOL_GPL'd while netpoll_send_udp() is still in
netpoll calling them, then those exports are dropped together once
netpoll_send_udp() itself moves.

The only new permanent export is zap_completion_queue(), needed because
find_skb() still drains the per-CPU TX completion queue before
allocating.

struct netpoll is unchanged in this series; making the pool itself
netconsole-private (and reclaiming the skb_pool / refill_wq fields for
the rest of netpoll's users) is the natural follow-up, once this patchset
lands.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Breno Leitao (8):
      netpoll: expose UDP packet builder helpers for netconsole
      netconsole: move netpoll_send_udp() from netpoll
      netconsole: move push_ipv6() from netpoll
      netconsole: move push_ipv4() from netpoll
      netconsole: move push_eth() from netpoll
      netconsole: move push_udp() from netpoll
      netconsole: move netpoll_udp_checksum() from netpoll
      netconsole: move find_skb() from netpoll

 drivers/net/netconsole.c | 174 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/netpoll.h  |   2 +-
 net/core/netpoll.c       | 180 +----------------------------------------------
 3 files changed, 178 insertions(+), 178 deletions(-)
---
base-commit: 6a4c4656b0d2d4056a1f0c35442db4e8a5cf8021
change-id: 20260508-netconsole_split-4f8402a9a9ff

Best regards,
--  
Breno Leitao <leitao@debian.org>

[PATCH net-next 1/8] netpoll: expose UDP packet builder helpers for netconsole

[Breno Leitao]

Promote each from file-static to EXPORT_SYMBOL_GPL and forward-
declare them in include/linux/netpoll.h so netconsole can call
them once netpoll_send_udp() moves out.

These exports are kept until the end of the series, when
al of them move into netconsole.

No functional change.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 include/linux/netpoll.h |  6 ++++++
 net/core/netpoll.c      | 20 +++++++++++++-------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index f22eec4660405..e68c80b329411 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -74,6 +74,12 @@ void __netpoll_free(struct netpoll *np);
 void netpoll_cleanup(struct netpoll *np);
 void do_netpoll_cleanup(struct netpoll *np);
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
+struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
+void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, int len);
+void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len);
+void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len);
+void push_udp(struct netpoll *np, struct sk_buff *skb, int len);
+void push_eth(struct netpoll *np, struct sk_buff *skb);
 
 #ifdef CONFIG_NETPOLL
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 84faace50ac28..41305056c56ff 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -268,7 +268,7 @@ static void zap_completion_queue(void)
 	put_cpu_var(softnet_data);
 }
 
-static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
+struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 {
 	int count = 0;
 	struct sk_buff *skb;
@@ -294,6 +294,7 @@ static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 	skb_reserve(skb, reserve);
 	return skb;
 }
+EXPORT_SYMBOL_GPL(find_skb);
 
 static int netpoll_owner_active(struct net_device *dev)
 {
@@ -369,8 +370,8 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 	return ret;
 }
 
-static void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
-				 int len)
+void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
+			  int len)
 {
 	struct udphdr *udph;
 	int udp_len;
@@ -393,6 +394,7 @@ static void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
 	if (udph->check == 0)
 		udph->check = CSUM_MANGLED_0;
 }
+EXPORT_SYMBOL_GPL(netpoll_udp_checksum);
 
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 {
@@ -411,7 +413,7 @@ netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(netpoll_send_skb);
 
-static void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len)
+void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	struct ipv6hdr *ip6h;
 
@@ -433,8 +435,9 @@ static void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len)
 
 	skb->protocol = htons(ETH_P_IPV6);
 }
+EXPORT_SYMBOL_GPL(push_ipv6);
 
-static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
+void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	static atomic_t ip_ident;
 	struct iphdr *iph;
@@ -460,8 +463,9 @@ static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
 	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
 	skb->protocol = htons(ETH_P_IP);
 }
+EXPORT_SYMBOL_GPL(push_ipv4);
 
-static void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
+void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	struct udphdr *udph;
 	int udp_len;
@@ -478,8 +482,9 @@ static void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
 
 	netpoll_udp_checksum(np, skb, len);
 }
+EXPORT_SYMBOL_GPL(push_udp);
 
-static void push_eth(struct netpoll *np, struct sk_buff *skb)
+void push_eth(struct netpoll *np, struct sk_buff *skb)
 {
 	struct ethhdr *eth;
 
@@ -492,6 +497,7 @@ static void push_eth(struct netpoll *np, struct sk_buff *skb)
 	else
 		eth->h_proto = htons(ETH_P_IP);
 }
+EXPORT_SYMBOL_GPL(push_eth);
 
 int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 {

-- 
2.53.0-Meta

[PATCH net-next 2/8] netconsole: move netpoll_send_udp() from netpoll

[Breno Leitao]

Move netpoll_send_udp() from net/core/netpoll.c into
drivers/net/netconsole.c as a static helper, drop EXPORT_SYMBOL(),
and remove the prototype from include/linux/netpoll.h.

netconsole was the only in-tree caller of this entry point. Every
other netpoll consumer (bonding, team, vlan, bridge, macvlan, dsa)
already builds its own sk_buff and hands it to netpoll_send_skb(),
so the netpoll send-side interface is now skb-only.

The helpers it depends on (find_skb(), push_ipv6(), push_ipv4(),
push_udp(), push_eth(), netpoll_udp_checksum()) were exposed in
the previous patches and stay in net/core/netpoll.c for now.
Subsequent patches move each of them into netconsole one at a time
and drop the corresponding EXPORT_SYMBOL_GPL.

Pull <linux/ip.h>, <linux/ipv6.h> and <linux/udp.h> into netconsole.c
so the moved code can name the header structures.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 38 ++++++++++++++++++++++++++++++++++++++
 include/linux/netpoll.h  |  1 -
 net/core/netpoll.c       | 37 -------------------------------------
 3 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 57dd6821a8aa9..56f310041ebda 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -32,6 +32,9 @@
 #include <linux/moduleparam.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/udp.h>
 #include <linux/netpoll.h>
 #include <linux/inet.h>
 #include <linux/configfs.h>
@@ -1648,6 +1651,41 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
+{
+	int total_len, ip_len, udp_len;
+	struct sk_buff *skb;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		WARN_ON_ONCE(!irqs_disabled());
+
+	udp_len = len + sizeof(struct udphdr);
+	if (np->ipv6)
+		ip_len = udp_len + sizeof(struct ipv6hdr);
+	else
+		ip_len = udp_len + sizeof(struct iphdr);
+
+	total_len = ip_len + LL_RESERVED_SPACE(np->dev);
+
+	skb = find_skb(np, total_len + np->dev->needed_tailroom,
+		       total_len - len);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_copy_to_linear_data(skb, msg, len);
+	skb_put(skb, len);
+
+	push_udp(np, skb, len);
+	if (np->ipv6)
+		push_ipv6(np, skb, len);
+	else
+		push_ipv4(np, skb, len);
+	push_eth(np, skb);
+	skb->dev = np->dev;
+
+	return (int)netpoll_send_skb(np, skb);
+}
+
 /**
  * send_udp - Wrapper for netpoll_send_udp that counts errors
  * @nt: target to send message to
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index e68c80b329411..57be72bb82dc9 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -67,7 +67,6 @@ static inline void netpoll_poll_disable(struct net_device *dev) { return; }
 static inline void netpoll_poll_enable(struct net_device *dev) { return; }
 #endif
 
-int netpoll_send_udp(struct netpoll *np, const char *msg, int len);
 int __netpoll_setup(struct netpoll *np, struct net_device *ndev);
 int netpoll_setup(struct netpoll *np);
 void __netpoll_free(struct netpoll *np);
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 41305056c56ff..39209308efad0 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -499,43 +499,6 @@ void push_eth(struct netpoll *np, struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(push_eth);
 
-int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
-{
-	int total_len, ip_len, udp_len;
-	struct sk_buff *skb;
-
-	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
-		WARN_ON_ONCE(!irqs_disabled());
-
-	udp_len = len + sizeof(struct udphdr);
-	if (np->ipv6)
-		ip_len = udp_len + sizeof(struct ipv6hdr);
-	else
-		ip_len = udp_len + sizeof(struct iphdr);
-
-	total_len = ip_len + LL_RESERVED_SPACE(np->dev);
-
-	skb = find_skb(np, total_len + np->dev->needed_tailroom,
-		       total_len - len);
-	if (!skb)
-		return -ENOMEM;
-
-	skb_copy_to_linear_data(skb, msg, len);
-	skb_put(skb, len);
-
-	push_udp(np, skb, len);
-	if (np->ipv6)
-		push_ipv6(np, skb, len);
-	else
-		push_ipv4(np, skb, len);
-	push_eth(np, skb);
-	skb->dev = np->dev;
-
-	return (int)netpoll_send_skb(np, skb);
-}
-EXPORT_SYMBOL(netpoll_send_udp);
-
-
 static void skb_pool_flush(struct netpoll *np)
 {
 	struct sk_buff_head *skb_pool;

-- 
2.53.0-Meta

[PATCH net-next 3/8] netconsole: move push_ipv6() from netpoll

[Breno Leitao]

push_ipv6() builds the IPv6 header for netconsole's UDP packets.
Its only caller, netpoll_send_udp(), now lives in netconsole, so
the helper can move there as a file-static function. Drop its
EXPORT_SYMBOL_GPL and remove the prototype from
include/linux/netpoll.h.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 23 +++++++++++++++++++++++
 include/linux/netpoll.h  |  1 -
 net/core/netpoll.c       | 24 ------------------------
 3 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 56f310041ebda..f805ae95ce7b1 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1651,6 +1651,29 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len)
+{
+	struct ipv6hdr *ip6h;
+
+	skb_push(skb, sizeof(struct ipv6hdr));
+	skb_reset_network_header(skb);
+	ip6h = ipv6_hdr(skb);
+
+	/* ip6h->version = 6; ip6h->priority = 0; */
+	*(unsigned char *)ip6h = 0x60;
+	ip6h->flow_lbl[0] = 0;
+	ip6h->flow_lbl[1] = 0;
+	ip6h->flow_lbl[2] = 0;
+
+	ip6h->payload_len = htons(sizeof(struct udphdr) + len);
+	ip6h->nexthdr = IPPROTO_UDP;
+	ip6h->hop_limit = 32;
+	ip6h->saddr = np->local_ip.in6;
+	ip6h->daddr = np->remote_ip.in6;
+
+	skb->protocol = htons(ETH_P_IPV6);
+}
+
 static int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 {
 	int total_len, ip_len, udp_len;
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 57be72bb82dc9..7f57bd0eac66d 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -75,7 +75,6 @@ void do_netpoll_cleanup(struct netpoll *np);
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
 struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
 void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, int len);
-void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len);
 void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len);
 void push_udp(struct netpoll *np, struct sk_buff *skb, int len);
 void push_eth(struct netpoll *np, struct sk_buff *skb);
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 39209308efad0..6a10ca5eaa093 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -413,30 +413,6 @@ netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(netpoll_send_skb);
 
-void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len)
-{
-	struct ipv6hdr *ip6h;
-
-	skb_push(skb, sizeof(struct ipv6hdr));
-	skb_reset_network_header(skb);
-	ip6h = ipv6_hdr(skb);
-
-	/* ip6h->version = 6; ip6h->priority = 0; */
-	*(unsigned char *)ip6h = 0x60;
-	ip6h->flow_lbl[0] = 0;
-	ip6h->flow_lbl[1] = 0;
-	ip6h->flow_lbl[2] = 0;
-
-	ip6h->payload_len = htons(sizeof(struct udphdr) + len);
-	ip6h->nexthdr = IPPROTO_UDP;
-	ip6h->hop_limit = 32;
-	ip6h->saddr = np->local_ip.in6;
-	ip6h->daddr = np->remote_ip.in6;
-
-	skb->protocol = htons(ETH_P_IPV6);
-}
-EXPORT_SYMBOL_GPL(push_ipv6);
-
 void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	static atomic_t ip_ident;

-- 
2.53.0-Meta

[PATCH net-next 4/8] netconsole: move push_ipv4() from netpoll

[Breno Leitao]

push_ipv4() builds the IPv4 header for netconsole's UDP packets.
Move it into drivers/net/netconsole.c as a file-static helper; drop
its EXPORT_SYMBOL_GPL and remove the prototype from
include/linux/netpoll.h.

put_unaligned() is no longer used in net/core/netpoll.c, so drop
the now-stale <linux/unaligned.h> include from there. Pull it into
netconsole.c so the moved code keeps building.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 28 ++++++++++++++++++++++++++++
 include/linux/netpoll.h  |  1 -
 net/core/netpoll.c       | 29 -----------------------------
 3 files changed, 28 insertions(+), 30 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index f805ae95ce7b1..84f90b53a10f7 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -37,6 +37,7 @@
 #include <linux/udp.h>
 #include <linux/netpoll.h>
 #include <linux/inet.h>
+#include <linux/unaligned.h>
 #include <linux/configfs.h>
 #include <linux/etherdevice.h>
 #include <linux/hex.h>
@@ -1651,6 +1652,33 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
+{
+	static atomic_t ip_ident;
+	struct iphdr *iph;
+	int ip_len;
+
+	ip_len = len + sizeof(struct udphdr) + sizeof(struct iphdr);
+
+	skb_push(skb, sizeof(struct iphdr));
+	skb_reset_network_header(skb);
+	iph = ip_hdr(skb);
+
+	/* iph->version = 4; iph->ihl = 5; */
+	*(unsigned char *)iph = 0x45;
+	iph->tos = 0;
+	put_unaligned(htons(ip_len), &iph->tot_len);
+	iph->id = htons(atomic_inc_return(&ip_ident));
+	iph->frag_off = 0;
+	iph->ttl = 64;
+	iph->protocol = IPPROTO_UDP;
+	iph->check = 0;
+	put_unaligned(np->local_ip.ip, &iph->saddr);
+	put_unaligned(np->remote_ip.ip, &iph->daddr);
+	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
+	skb->protocol = htons(ETH_P_IP);
+}
+
 static void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	struct ipv6hdr *ip6h;
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 7f57bd0eac66d..1fcde9c87b8c2 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -75,7 +75,6 @@ void do_netpoll_cleanup(struct netpoll *np);
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
 struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
 void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, int len);
-void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len);
 void push_udp(struct netpoll *np, struct sk_buff *skb, int len);
 void push_eth(struct netpoll *np, struct sk_buff *skb);
 
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 6a10ca5eaa093..030424e43bfb4 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -34,7 +34,6 @@
 #include <net/addrconf.h>
 #include <net/ndisc.h>
 #include <net/ip6_checksum.h>
-#include <linux/unaligned.h>
 #include <trace/events/napi.h>
 #include <linux/kconfig.h>
 
@@ -413,34 +412,6 @@ netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(netpoll_send_skb);
 
-void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
-{
-	static atomic_t ip_ident;
-	struct iphdr *iph;
-	int ip_len;
-
-	ip_len = len + sizeof(struct udphdr) + sizeof(struct iphdr);
-
-	skb_push(skb, sizeof(struct iphdr));
-	skb_reset_network_header(skb);
-	iph = ip_hdr(skb);
-
-	/* iph->version = 4; iph->ihl = 5; */
-	*(unsigned char *)iph = 0x45;
-	iph->tos = 0;
-	put_unaligned(htons(ip_len), &iph->tot_len);
-	iph->id = htons(atomic_inc_return(&ip_ident));
-	iph->frag_off = 0;
-	iph->ttl = 64;
-	iph->protocol = IPPROTO_UDP;
-	iph->check = 0;
-	put_unaligned(np->local_ip.ip, &iph->saddr);
-	put_unaligned(np->remote_ip.ip, &iph->daddr);
-	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
-	skb->protocol = htons(ETH_P_IP);
-}
-EXPORT_SYMBOL_GPL(push_ipv4);
-
 void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	struct udphdr *udph;

-- 
2.53.0-Meta

[PATCH net-next 5/8] netconsole: move push_eth() from netpoll

[Breno Leitao]

push_eth() builds the Ethernet header for netconsole's UDP packets.
Move it into drivers/net/netconsole.c as a file-static helper; drop
its EXPORT_SYMBOL_GPL and remove the prototype from
include/linux/netpoll.h.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 14 ++++++++++++++
 include/linux/netpoll.h  |  1 -
 net/core/netpoll.c       | 15 ---------------
 3 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 84f90b53a10f7..bcedc161b13ec 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1652,6 +1652,20 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static void push_eth(struct netpoll *np, struct sk_buff *skb)
+{
+	struct ethhdr *eth;
+
+	eth = skb_push(skb, ETH_HLEN);
+	skb_reset_mac_header(skb);
+	ether_addr_copy(eth->h_source, np->dev->dev_addr);
+	ether_addr_copy(eth->h_dest, np->remote_mac);
+	if (np->ipv6)
+		eth->h_proto = htons(ETH_P_IPV6);
+	else
+		eth->h_proto = htons(ETH_P_IP);
+}
+
 static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	static atomic_t ip_ident;
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 1fcde9c87b8c2..11eb95b3248e2 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -76,7 +76,6 @@ netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
 struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
 void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, int len);
 void push_udp(struct netpoll *np, struct sk_buff *skb, int len);
-void push_eth(struct netpoll *np, struct sk_buff *skb);
 
 #ifdef CONFIG_NETPOLL
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 030424e43bfb4..12165667705f3 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -431,21 +431,6 @@ void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
 }
 EXPORT_SYMBOL_GPL(push_udp);
 
-void push_eth(struct netpoll *np, struct sk_buff *skb)
-{
-	struct ethhdr *eth;
-
-	eth = skb_push(skb, ETH_HLEN);
-	skb_reset_mac_header(skb);
-	ether_addr_copy(eth->h_source, np->dev->dev_addr);
-	ether_addr_copy(eth->h_dest, np->remote_mac);
-	if (np->ipv6)
-		eth->h_proto = htons(ETH_P_IPV6);
-	else
-		eth->h_proto = htons(ETH_P_IP);
-}
-EXPORT_SYMBOL_GPL(push_eth);
-
 static void skb_pool_flush(struct netpoll *np)
 {
 	struct sk_buff_head *skb_pool;

-- 
2.53.0-Meta

[PATCH net-next 6/8] netconsole: move push_udp() from netpoll

[Breno Leitao]

push_udp() builds the UDP header (and triggers the checksum) for
netconsole's UDP packets. Move it into drivers/net/netconsole.c as
a file-static helper; drop its EXPORT_SYMBOL_GPL and remove the
prototype from include/linux/netpoll.h.

push_udp() was the last udp_hdr() consumer in net/core/netpoll.c,
so swap <net/udp.h> for <linux/udp.h> there: MAX_SKB_SIZE still
needs struct udphdr.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 18 ++++++++++++++++++
 include/linux/netpoll.h  |  1 -
 net/core/netpoll.c       | 21 +--------------------
 3 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index bcedc161b13ec..e8d96e482fe05 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1652,6 +1652,24 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
+{
+	struct udphdr *udph;
+	int udp_len;
+
+	udp_len = len + sizeof(struct udphdr);
+
+	skb_push(skb, sizeof(struct udphdr));
+	skb_reset_transport_header(skb);
+
+	udph = udp_hdr(skb);
+	udph->source = htons(np->local_port);
+	udph->dest = htons(np->remote_port);
+	udph->len = htons(udp_len);
+
+	netpoll_udp_checksum(np, skb, len);
+}
+
 static void push_eth(struct netpoll *np, struct sk_buff *skb)
 {
 	struct ethhdr *eth;
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 11eb95b3248e2..03a49953a3d8a 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -75,7 +75,6 @@ void do_netpoll_cleanup(struct netpoll *np);
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
 struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
 void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, int len);
-void push_udp(struct netpoll *np, struct sk_buff *skb, int len);
 
 #ifdef CONFIG_NETPOLL
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 12165667705f3..4ec9e309dfe6c 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -29,8 +29,8 @@
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/if_vlan.h>
+#include <linux/udp.h>
 #include <net/tcp.h>
-#include <net/udp.h>
 #include <net/addrconf.h>
 #include <net/ndisc.h>
 #include <net/ip6_checksum.h>
@@ -412,25 +412,6 @@ netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(netpoll_send_skb);
 
-void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
-{
-	struct udphdr *udph;
-	int udp_len;
-
-	udp_len = len + sizeof(struct udphdr);
-
-	skb_push(skb, sizeof(struct udphdr));
-	skb_reset_transport_header(skb);
-
-	udph = udp_hdr(skb);
-	udph->source = htons(np->local_port);
-	udph->dest = htons(np->remote_port);
-	udph->len = htons(udp_len);
-
-	netpoll_udp_checksum(np, skb, len);
-}
-EXPORT_SYMBOL_GPL(push_udp);
-
 static void skb_pool_flush(struct netpoll *np)
 {
 	struct sk_buff_head *skb_pool;

-- 
2.53.0-Meta

[PATCH net-next 7/8] netconsole: move netpoll_udp_checksum() from netpoll

[Breno Leitao]

netpoll_udp_checksum() computes the UDP checksum for netconsole's
packets. Move it into drivers/net/netconsole.c as a file-static
helper; drop its EXPORT_SYMBOL_GPL and remove the prototype from
include/linux/netpoll.h.

This was the last csum_ipv6_magic() consumer in
net/core/netpoll.c, so drop the now-stale <net/ip6_checksum.h>
include there. Pull it into netconsole.c so the moved code keeps
building.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 26 ++++++++++++++++++++++++++
 include/linux/netpoll.h  |  1 -
 net/core/netpoll.c       | 27 ---------------------------
 3 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index e8d96e482fe05..48d2670bbdef5 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -38,6 +38,7 @@
 #include <linux/netpoll.h>
 #include <linux/inet.h>
 #include <linux/unaligned.h>
+#include <net/ip6_checksum.h>
 #include <linux/configfs.h>
 #include <linux/etherdevice.h>
 #include <linux/hex.h>
@@ -1652,6 +1653,31 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
+				 int len)
+{
+	struct udphdr *udph;
+	int udp_len;
+
+	udp_len = len + sizeof(struct udphdr);
+	udph = udp_hdr(skb);
+
+	/* check needs to be set, since it will be consumed in csum_partial */
+	udph->check = 0;
+	if (np->ipv6)
+		udph->check = csum_ipv6_magic(&np->local_ip.in6,
+					      &np->remote_ip.in6,
+					      udp_len, IPPROTO_UDP,
+					      csum_partial(udph, udp_len, 0));
+	else
+		udph->check = csum_tcpudp_magic(np->local_ip.ip,
+						np->remote_ip.ip,
+						udp_len, IPPROTO_UDP,
+						csum_partial(udph, udp_len, 0));
+	if (udph->check == 0)
+		udph->check = CSUM_MANGLED_0;
+}
+
 static void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
 {
 	struct udphdr *udph;
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 03a49953a3d8a..1877d42ccbccf 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -74,7 +74,6 @@ void netpoll_cleanup(struct netpoll *np);
 void do_netpoll_cleanup(struct netpoll *np);
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
 struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
-void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, int len);
 
 #ifdef CONFIG_NETPOLL
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 4ec9e309dfe6c..c148b3b68cec9 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -33,7 +33,6 @@
 #include <net/tcp.h>
 #include <net/addrconf.h>
 #include <net/ndisc.h>
-#include <net/ip6_checksum.h>
 #include <trace/events/napi.h>
 #include <linux/kconfig.h>
 
@@ -369,32 +368,6 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 	return ret;
 }
 
-void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
-			  int len)
-{
-	struct udphdr *udph;
-	int udp_len;
-
-	udp_len = len + sizeof(struct udphdr);
-	udph = udp_hdr(skb);
-
-	/* check needs to be set, since it will be consumed in csum_partial */
-	udph->check = 0;
-	if (np->ipv6)
-		udph->check = csum_ipv6_magic(&np->local_ip.in6,
-					      &np->remote_ip.in6,
-					      udp_len, IPPROTO_UDP,
-					      csum_partial(udph, udp_len, 0));
-	else
-		udph->check = csum_tcpudp_magic(np->local_ip.ip,
-						np->remote_ip.ip,
-						udp_len, IPPROTO_UDP,
-						csum_partial(udph, udp_len, 0));
-	if (udph->check == 0)
-		udph->check = CSUM_MANGLED_0;
-}
-EXPORT_SYMBOL_GPL(netpoll_udp_checksum);
-
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 {
 	unsigned long flags;

-- 
2.53.0-Meta

[PATCH net-next 8/8] netconsole: move find_skb() from netpoll

[Breno Leitao]

find_skb() is the netconsole-specific entry into the netpoll skb
pool: every other netpoll consumer (bonding, team, vlan, bridge,
macvlan, dsa) builds its own sk_buff and never touches the pool.
With netpoll_send_udp() (its only caller) now living in netconsole,
find_skb() can join it.

Move find_skb() into drivers/net/netconsole.c as a file-static
helper, drop EXPORT_SYMBOL_GPL(find_skb) and remove its prototype
from include/linux/netpoll.h.

find_skb() calls zap_completion_queue() to drain TX completions
before allocating. zap_completion_queue() also has a second caller
inside netpoll itself (netpoll_poll_dev() runs it after each poll
to free completed skbs), so it stays in net/core/netpoll.c.
Promote it from file-static to EXPORT_SYMBOL_GPL with a forward
declaration in include/linux/netpoll.h, and drop its old
file-static forward declaration.

The skb pool's lifecycle (np->skb_pool, np->refill_wq, refill_skbs(),
refill_skbs_work_handler(), skb_pool_flush()) stays in netpoll: it
is initialised in __netpoll_setup() and torn down in
__netpoll_cleanup(), both of which remain netpoll's responsibility.
The refill work queued via schedule_work(&np->refill_wq) from the
moved find_skb() runs refill_skbs_work_handler() in netpoll without
any further plumbing.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 27 +++++++++++++++++++++++++++
 include/linux/netpoll.h  |  2 +-
 net/core/netpoll.c       | 33 ++-------------------------------
 3 files changed, 30 insertions(+), 32 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 48d2670bbdef5..817561d8b06bb 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1653,6 +1653,33 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
+{
+	int count = 0;
+	struct sk_buff *skb;
+
+	zap_completion_queue();
+repeat:
+
+	skb = alloc_skb(len, GFP_ATOMIC);
+	if (!skb) {
+		skb = skb_dequeue(&np->skb_pool);
+		schedule_work(&np->refill_wq);
+	}
+
+	if (!skb) {
+		if (++count < 10) {
+			netpoll_poll_dev(np->dev);
+			goto repeat;
+		}
+		return NULL;
+	}
+
+	refcount_set(&skb->users, 1);
+	skb_reserve(skb, reserve);
+	return skb;
+}
+
 static void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
 				 int len)
 {
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 1877d42ccbccf..c9a03d88263ef 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -73,7 +73,7 @@ void __netpoll_free(struct netpoll *np);
 void netpoll_cleanup(struct netpoll *np);
 void do_netpoll_cleanup(struct netpoll *np);
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
-struct sk_buff *find_skb(struct netpoll *np, int len, int reserve);
+void zap_completion_queue(void);
 
 #ifdef CONFIG_NETPOLL
 static inline void *netpoll_poll_lock(struct napi_struct *napi)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c148b3b68cec9..956528904050e 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -51,8 +51,6 @@
 	 sizeof(struct udphdr) +					\
 	 MAX_UDP_CHUNK)
 
-static void zap_completion_queue(void);
-
 static unsigned int carrier_timeout = 4;
 module_param(carrier_timeout, uint, 0644);
 
@@ -238,7 +236,7 @@ static void refill_skbs(struct netpoll *np)
 	}
 }
 
-static void zap_completion_queue(void)
+void zap_completion_queue(void)
 {
 	unsigned long flags;
 	struct softnet_data *sd = &get_cpu_var(softnet_data);
@@ -265,34 +263,7 @@ static void zap_completion_queue(void)
 
 	put_cpu_var(softnet_data);
 }
-
-struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
-{
-	int count = 0;
-	struct sk_buff *skb;
-
-	zap_completion_queue();
-repeat:
-
-	skb = alloc_skb(len, GFP_ATOMIC);
-	if (!skb) {
-		skb = skb_dequeue(&np->skb_pool);
-		schedule_work(&np->refill_wq);
-	}
-
-	if (!skb) {
-		if (++count < 10) {
-			netpoll_poll_dev(np->dev);
-			goto repeat;
-		}
-		return NULL;
-	}
-
-	refcount_set(&skb->users, 1);
-	skb_reserve(skb, reserve);
-	return skb;
-}
-EXPORT_SYMBOL_GPL(find_skb);
+EXPORT_SYMBOL_GPL(zap_completion_queue);
 
 static int netpoll_owner_active(struct net_device *dev)
 {

-- 
2.53.0-Meta

Re: [PATCH net-next 8/8] netconsole: move find_skb() from netpoll

[Jakub Kicinski]

On Fri, 08 May 2026 06:29:22 -0700 Breno Leitao wrote:
> +EXPORT_SYMBOL_GPL(zap_completion_queue);

We should probably rename it to add an appropriate prefix.
netpoll_ or net_ ? And maybe export it as NETDEV_INTERNAL?