From 2fbebfbe2953bc0ba1656b25d03338fde1066ad5 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Fri, 10 Jul 2026 04:38:57 -0700 Subject: [PATCH] netconsole: move refill_skbs() and skb-pool sizing macros from netpoll refill_skbs() is now only called from netconsole (directly via netconsole_skb_pool_init() and indirectly via the just-moved refill_skbs_work_handler()), and the MAX_UDP_CHUNK / MAX_SKBS / MAX_SKB_SIZE macros are private to it. Move them all into drivers/net/netconsole.c. MAX_UDP_CHUNK and MAX_SKB_SIZE were promoted to by commit 6c537b845c99 ("netconsole: do not dequeue pooled skbs that cannot satisfy len") so find_skb() could detect oversized requests against the same value refill_skbs() used. With both functions now local to netconsole, the shared definition no longer needs to live in the header. Pure code motion: bodies and pool sizing semantics are unchanged. Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20260710-netconsole_move_more-v3-5-6f63f76b28bc@debian.org Reviewed-by: Simon Horman Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 29 +++++++++++++++++++++++++++++ include/linux/netpoll.h | 15 --------------- net/core/netpoll.c | 23 ----------------------- 3 files changed, 29 insertions(+), 38 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 96d9a47312cd..efeada762536 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -61,6 +61,19 @@ MODULE_IMPORT_NS("NETDEV_INTERNAL"); #define MAX_USERDATA_ITEMS 256 #define MAX_PRINT_CHUNK 1000 +/* + * Sizing for the per-target fallback skb pool consulted by find_skb() + * when its GFP_ATOMIC allocation fails so messages still get out under + * memory pressure. + */ +#define MAX_UDP_CHUNK 1460 +#define MAX_SKBS 32 +#define MAX_SKB_SIZE \ + (sizeof(struct ethhdr) + \ + sizeof(struct iphdr) + \ + sizeof(struct udphdr) + \ + MAX_UDP_CHUNK) + static char config[MAX_PARAM_LENGTH]; module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0); MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@/[tgt-macaddr]"); @@ -292,6 +305,22 @@ static void netcons_release_dev(struct netconsole_target *nt) memset(&nt->np.dev_name, 0, IFNAMSIZ); } +static void refill_skbs(struct netpoll *np) +{ + struct sk_buff_head *skb_pool; + struct sk_buff *skb; + + skb_pool = &np->skb_pool; + + while (READ_ONCE(skb_pool->qlen) < MAX_SKBS) { + skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC | __GFP_NOWARN); + if (!skb) + break; + + skb_queue_tail(skb_pool, skb); + } +} + static void refill_skbs_work_handler(struct work_struct *work) { struct netpoll *np = diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index 51e5863d8e67..7e2fbce863e9 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -21,20 +21,6 @@ union inet_addr { struct in6_addr in6; }; -/* - * Maximum payload netpoll's preallocated skb pool can carry. Keep this in - * sync with the buffer size used by refill_skbs() in net/core/netpoll.c; - * callers (e.g. netconsole) use it to detect requests the pool can never - * satisfy and avoid dequeuing a pooled skb that would later trip - * skb_over_panic() in skb_put(). - */ -#define MAX_UDP_CHUNK 1460 -#define MAX_SKB_SIZE \ - (sizeof(struct ethhdr) + \ - sizeof(struct iphdr) + \ - sizeof(struct udphdr) + \ - MAX_UDP_CHUNK) - struct netpoll { struct net_device *dev; netdevice_tracker dev_tracker; @@ -90,7 +76,6 @@ 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); void netpoll_zap_completion_queue(void); -void refill_skbs(struct netpoll *np); void skb_pool_flush(struct netpoll *np); #ifdef CONFIG_NETPOLL diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 93a16faf808c..9ca695f64210 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -36,12 +36,6 @@ #include #include -/* - * We maintain a small pool of fully-sized skbs, to make sure the - * message gets out even in extreme OOM situations. - */ - -#define MAX_SKBS 32 #define USEC_PER_POLL 50 static unsigned int carrier_timeout = 4; @@ -213,23 +207,6 @@ void netpoll_poll_enable(struct net_device *dev) up(&ni->dev_lock); } -void refill_skbs(struct netpoll *np) -{ - struct sk_buff_head *skb_pool; - struct sk_buff *skb; - - skb_pool = &np->skb_pool; - - while (READ_ONCE(skb_pool->qlen) < MAX_SKBS) { - skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC | __GFP_NOWARN); - if (!skb) - break; - - skb_queue_tail(skb_pool, skb); - } -} -EXPORT_SYMBOL_GPL(refill_skbs); - void netpoll_zap_completion_queue(void) { unsigned long flags;