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author | Johannes Berg <johannes.berg@intel.com> | 2023-04-19 14:52:53 +0200 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2023-04-20 20:20:49 -0700 |
commit | 071c0fc6fb919dcf29c676a842dda08a674877d7 (patch) | |
tree | 7062c1fde75461ef4cb2a5a3395f6d56b8812b70 /net/core/skbuff.c | |
parent | 5b8285cca6fed9bc5baabe2e5699a5a5c0d96371 (diff) | |
download | linux-071c0fc6fb919dcf29c676a842dda08a674877d7.tar.gz linux-071c0fc6fb919dcf29c676a842dda08a674877d7.tar.bz2 linux-071c0fc6fb919dcf29c676a842dda08a674877d7.zip |
net: extend drop reasons for multiple subsystems
Extend drop reasons to make them usable by subsystems
other than core by reserving the high 16 bits for a
new subsystem ID, of which 0 of course is used for the
existing reasons immediately.
To still be able to have string reasons, restructure
that code a bit to make the loopup under RCU, the only
user of this (right now) is drop_monitor.
Link: https://lore.kernel.org/netdev/00659771ed54353f92027702c5bbb84702da62ce.camel@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r-- | net/core/skbuff.c | 59 |
1 files changed, 56 insertions, 3 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 8764653bede7..0d998806b377 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -58,6 +58,7 @@ #include <linux/scatterlist.h> #include <linux/errqueue.h> #include <linux/prefetch.h> +#include <linux/bitfield.h> #include <linux/if_vlan.h> #include <linux/mpls.h> #include <linux/kcov.h> @@ -72,6 +73,7 @@ #include <net/mptcp.h> #include <net/mctp.h> #include <net/page_pool.h> +#include <net/dropreason.h> #include <linux/uaccess.h> #include <trace/events/skb.h> @@ -122,11 +124,59 @@ EXPORT_SYMBOL(sysctl_max_skb_frags); #undef FN #define FN(reason) [SKB_DROP_REASON_##reason] = #reason, -const char * const drop_reasons[] = { +static const char * const drop_reasons[] = { [SKB_CONSUMED] = "CONSUMED", DEFINE_DROP_REASON(FN, FN) }; -EXPORT_SYMBOL(drop_reasons); + +static const struct drop_reason_list drop_reasons_core = { + .reasons = drop_reasons, + .n_reasons = ARRAY_SIZE(drop_reasons), +}; + +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); + +/** + * drop_reasons_register_subsys - register another drop reason subsystem + * @subsys: the subsystem to register, must not be the core + * @list: the list of drop reasons within the subsystem, must point to + * a statically initialized list + */ +void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys, + const struct drop_reason_list *list) +{ + if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE || + subsys >= ARRAY_SIZE(drop_reasons_by_subsys), + "invalid subsystem %d\n", subsys)) + return; + + /* must point to statically allocated memory, so INIT is OK */ + RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], list); +} +EXPORT_SYMBOL_GPL(drop_reasons_register_subsys); + +/** + * drop_reasons_unregister_subsys - unregister a drop reason subsystem + * @subsys: the subsystem to remove, must not be the core + * + * Note: This will synchronize_rcu() to ensure no users when it returns. + */ +void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys) +{ + if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE || + subsys >= ARRAY_SIZE(drop_reasons_by_subsys), + "invalid subsystem %d\n", subsys)) + return; + + RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], NULL); + + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(drop_reasons_unregister_subsys); /** * skb_panic - private function for out-of-line support @@ -986,7 +1036,10 @@ bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason) if (unlikely(!skb_unref(skb))) return false; - DEBUG_NET_WARN_ON_ONCE(reason <= 0 || reason >= SKB_DROP_REASON_MAX); + DEBUG_NET_WARN_ON_ONCE(reason == SKB_NOT_DROPPED_YET || + u32_get_bits(reason, + SKB_DROP_REASON_SUBSYS_MASK) >= + SKB_DROP_REASON_SUBSYS_NUM); if (reason == SKB_CONSUMED) trace_consume_skb(skb, __builtin_return_address(0)); |