From a9e3760b0838299649c0d57cca44daaf40ba3c33 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Sep 2026 22:12:34 -1000 Subject: sched_ext: Maintain an online cid mask in the scheduler arena Schedulers on the default cid mapping treat [0, nr_online_cids) as the online set and restart on hotplug. Schedulers that install their own mapping with scx_bpf_cid_override() have no way to learn which cids are online: the count no longer identifies members and the CPU-form cpumask is unusable from cid programs. This is an obvious hole in the cid API. Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's arena, allocated alongside the per-CPU scratch masks and populated after the cid mapping is finalized and before ops.init(), for child schedulers too. The pointer stays valid through ops.exit() with no reference to take. It is the arena offset as a void pointer, the same form struct_ops arena arguments arrive in. The verifier types the void return as a scalar for the program's arena cast. The mask follows the SCX hotplug notifications: seeded from cpu_active_mask and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask only inside a hotplug transition. Updates walk the scheduler list under the lock that also serializes unlinking. Reads are live, not atomic snapshots. Root initialization excludes hotplug. v2: Reworded the getter kerneldoc (Andrea Righi). Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- include/net/protocol.h | 119 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) create mode 100644 include/net/protocol.h (limited to 'include/net/protocol.h') diff --git a/include/net/protocol.h b/include/net/protocol.h new file mode 100644 index 000000000..b2499f88f --- /dev/null +++ b/include/net/protocol.h @@ -0,0 +1,119 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * Definitions for the protocol dispatcher. + * + * Version: @(#)protocol.h 1.0.2 05/07/93 + * + * Author: Fred N. van Kempen, + * + * Changes: + * Alan Cox : Added a name field and a frag handler + * field for later. + * Alan Cox : Cleaned up, and sorted types. + * Pedro Roque : inet6 protocols + */ + +#ifndef _PROTOCOL_H +#define _PROTOCOL_H + +#include +#include +#if IS_ENABLED(CONFIG_IPV6) +#include +#endif +#include + +/* This is one larger than the largest protocol value that can be + * found in an ipv4 or ipv6 header. Since in both cases the protocol + * value is presented in a __u8, this is defined to be 256. + */ +#define MAX_INET_PROTOS 256 + +/* This is used to register protocols. */ +struct net_protocol { + int (*handler)(struct sk_buff *skb); + + /* This returns an error if we weren't able to handle the error. */ + int (*err_handler)(struct sk_buff *skb, u32 info); + + unsigned int no_policy:1, + /* does the protocol do more stringent + * icmp tag validation than simple + * socket lookup? + */ + icmp_strict_tag_validation:1; + u32 secret; +}; + +#if IS_ENABLED(CONFIG_IPV6) +struct inet6_protocol { + int (*handler)(struct sk_buff *skb); + + /* This returns an error if we weren't able to handle the error. */ + int (*err_handler)(struct sk_buff *skb, + struct inet6_skb_parm *opt, + u8 type, u8 code, int offset, + __be32 info); + + unsigned int flags; /* INET6_PROTO_xxx */ + u32 secret; +}; + +#define INET6_PROTO_NOPOLICY 0x1 +#define INET6_PROTO_FINAL 0x2 +#endif + +struct net_offload { + struct offload_callbacks callbacks; + unsigned int flags; /* Flags used by IPv6 for now */ + u32 secret; +}; +/* This should be set for any extension header which is compatible with GSO. */ +#define INET6_PROTO_GSO_EXTHDR 0x1 + +/* This is used to register socket interfaces for IP protocols. */ +struct inet_protosw { + struct list_head list; + + /* These two fields form the lookup key. */ + unsigned short type; /* This is the 2nd argument to socket(2). */ + unsigned short protocol; /* This is the L4 protocol number. */ + + struct proto *prot; + const struct proto_ops *ops; + + unsigned char flags; /* See INET_PROTOSW_* below. */ +}; +#define INET_PROTOSW_REUSE 0x01 /* Are ports automatically reusable? */ +#define INET_PROTOSW_PERMANENT 0x02 /* Permanent protocols are unremovable. */ +#define INET_PROTOSW_ICSK 0x04 /* Is this an inet_connection_sock? */ + +extern struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS]; +extern const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS]; +extern const struct net_offload __rcu *inet6_offloads[MAX_INET_PROTOS]; + +#if IS_ENABLED(CONFIG_IPV6) +extern struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS]; +#endif + +int inet_add_protocol(const struct net_protocol *prot, unsigned char num); +int inet_del_protocol(const struct net_protocol *prot, unsigned char num); +int inet_add_offload(const struct net_offload *prot, unsigned char num); +int inet_del_offload(const struct net_offload *prot, unsigned char num); +void inet_register_protosw(struct inet_protosw *p); +void inet_unregister_protosw(struct inet_protosw *p); + +#if IS_ENABLED(CONFIG_IPV6) +int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char num); +int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char num); +int inet6_register_protosw(struct inet_protosw *p); +void inet6_unregister_protosw(struct inet_protosw *p); +#endif +int inet6_add_offload(const struct net_offload *prot, unsigned char num); +int inet6_del_offload(const struct net_offload *prot, unsigned char num); + +#endif /* _PROTOCOL_H */ -- cgit v1.3.1