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netconsole: move refill_skbs() and skb-pool sizing macros from netpoll

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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 <linux/netpoll.h>
by commit 6c537b845c ("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 <leitao@debian.org>
Link: https://patch.msgid.link/20260710-netconsole_move_more-v3-5-6f63f76b28bc@debian.org
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Breno Leitao
2026-07-10 04:38:57 -07:00
committed by Paolo Abeni
parent 2851128908
commit 2fbebfbe29
3 changed files with 29 additions and 38 deletions
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29
drivers/net/netconsole.c
View File

@@ -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-ip>/[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 =

15
include/linux/netpoll.h
View File

@@ -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

23
net/core/netpoll.c
View File

@@ -36,12 +36,6 @@
#include <trace/events/napi.h>
#include <linux/kconfig.h>
/*
* 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;