[PATCH net-next v2 9/9] netconsole: move find_skb() from netpoll
From: Breno Leitao <leitao@debian.org>
Date: 2026-05-12 10:49:02
Also in:
linux-rt-devel, lkml
Subsystem:
netconsole, networking drivers, networking [general], the rest · Maintainers:
Breno Leitao, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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() drains TX completions via
netpoll_zap_completion_queue(), which is already exported in the
NETDEV_INTERNAL namespace, so netconsole picks up
MODULE_IMPORT_NS("NETDEV_INTERNAL") to consume it.
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.
This is pure code motion: the function body is unchanged and its
sole caller (netpoll_send_udp(), already moved by an earlier patch)
keeps invoking it the same way. Pre-existing concerns about
find_skb() running from NMI/printk context (zap_completion_queue()
re-entry, skb_pool spinlocks, GFP_ATOMIC allocation, fallback skb
sizing vs. MAX_SKB_SIZE, PREEMPT_RT semantics of __kfree_skb()) are
inherited as-is and are not addressed here; they predate this
series and are out of scope. Fixing them is left for follow-up
work.
Signed-off-by: Breno Leitao <leitao@debian.org>
---
drivers/net/netconsole.c | 28 ++++++++++++++++++++++++++++
include/linux/netpoll.h | 1 -
net/core/netpoll.c | 28 ----------------------------
3 files changed, 28 insertions(+), 29 deletions(-)
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 48d2670bbdef5..d804d44af87c8 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c@@ -50,6 +50,7 @@ MODULE_AUTHOR("Matt Mackall <mpm@selenic.com>"); MODULE_DESCRIPTION("Console driver for network interfaces"); MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("NETDEV_INTERNAL"); #define MAX_PARAM_LENGTH 256 #define MAX_EXTRADATA_ENTRY_LEN 256
@@ -1653,6 +1654,33 @@ 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; + + netpoll_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 f986f7486cb8c..e4b8f1f91e54b 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h@@ -73,7 +73,6 @@ 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_zap_completion_queue(void); #ifdef CONFIG_NETPOLL
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index e4cda0aa4d488..33ab3d827a427 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c@@ -265,34 +265,6 @@ void netpoll_zap_completion_queue(void) } EXPORT_SYMBOL_NS_GPL(netpoll_zap_completion_queue, "NETDEV_INTERNAL"); -struct sk_buff *find_skb(struct netpoll *np, int len, int reserve) -{ - int count = 0; - struct sk_buff *skb; - - netpoll_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); - static int netpoll_owner_active(struct net_device *dev) { struct napi_struct *napi;
--
2.53.0-Meta