[PATCH v7 4/4] net: drop_monitor: use drop_reason_lookup()
COOLING4d
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2026-09-22 11:10:09
Also in:
lkml, netdev
Subsystem:
network drop monitor, networking [general], the rest · Maintainers:
Neil Horman, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Revision v7 of 7 in this series.
Revisions (7)
From: Johannes Berg <redacted>
Now that we have drop_reason_lookup(), we can just use it for
drop_monitor as well, rather than exporting the list itself.
Signed-off-by: Johannes Berg <redacted>
---
v7: don't hide drop_reason_show() prototype (sashiko,
but it got it the wrong way around)
---
include/net/dropreason.h | 5 +----
net/core/drop_monitor.c | 20 +++++---------------
net/core/skbuff.c | 6 +++---
3 files changed, 9 insertions(+), 22 deletions(-)
diff --git a/include/net/dropreason.h b/include/net/dropreason.h
index dc4a60130c09..537428c72642 100644
--- a/include/net/dropreason.h
+++ b/include/net/dropreason.h@@ -38,12 +38,9 @@ struct drop_reason_list { size_t n_reasons; }; -/* Note: due to dynamic registrations, access must be under RCU */ -extern const struct drop_reason_list __rcu * -drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM]; +const char *drop_reason_lookup(unsigned long long value); #ifdef CONFIG_TRACEPOINTS -const char *drop_reason_lookup(unsigned long long value); void drop_reason_show(struct seq_file *m); #endif
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index edc660778408..5aa7692c5df2 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c@@ -611,9 +611,8 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, size_t payload_len) { struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); - const struct drop_reason_list *list = NULL; - unsigned int subsys, subsys_reason; char buf[NET_DM_MAX_SYMBOL_LEN]; + const char *reason_str; struct nlattr *attr; void *hdr; int rc;
@@ -631,19 +630,10 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, goto nla_put_failure; rcu_read_lock(); - subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK); - if (subsys < SKB_DROP_REASON_SUBSYS_NUM) - list = rcu_dereference(drop_reasons_by_subsys[subsys]); - subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK; - if (!list || - subsys_reason >= list->n_reasons || - !list->reasons[subsys_reason] || - strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) { - list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]); - subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED; - } - if (nla_put_string(msg, NET_DM_ATTR_REASON, - list->reasons[subsys_reason])) { + reason_str = drop_reason_lookup(cb->reason); + if (unlikely(!reason_str)) + reason_str = drop_reason_lookup(SKB_DROP_REASON_NOT_SPECIFIED); + if (nla_put_string(msg, NET_DM_ATTR_REASON, reason_str)) { rcu_read_unlock(); goto nla_put_failure; }
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 8c8f7a05dea4..c675d3330937 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -148,13 +148,11 @@ static const struct drop_reason_list drop_reasons_core = { .n_reasons = ARRAY_SIZE(drop_reasons), }; -const struct drop_reason_list __rcu * +static const struct drop_reason_list __rcu * drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM] = { [SKB_DROP_REASON_SUBSYS_CORE] = RCU_INITIALIZER(&drop_reasons_core), }; -EXPORT_SYMBOL(drop_reasons_by_subsys); -#ifdef CONFIG_TRACEPOINTS const char *drop_reason_lookup(unsigned long long value) { unsigned long long subsys_id = value >> SKB_DROP_REASON_SUBSYS_SHIFT;
@@ -171,7 +169,9 @@ const char *drop_reason_lookup(unsigned long long value) return NULL; return subsys->reasons[reason]; } +EXPORT_SYMBOL(drop_reason_lookup); +#ifdef CONFIG_TRACEPOINTS void drop_reason_show(struct seq_file *m) { u32 subsys_id;
--
2.55.0