Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.

1 files changed, 90 insertions, 0 deletions

diff --git a/include/net/pfcp.h b/include/net/pfcp.h
new file mode 100644
index 000000000..639553797
--- /dev/null
+++ b/include/net/pfcp.h
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PFCP_H_
+#define _PFCP_H_
+
+#include <uapi/linux/if_ether.h>
+#include <net/dst_metadata.h>
+#include <linux/netdevice.h>
+#include <uapi/linux/ipv6.h>
+#include <net/udp_tunnel.h>
+#include <uapi/linux/udp.h>
+#include <uapi/linux/ip.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/bits.h>
+
+#define PFCP_PORT 8805
+
+/* PFCP protocol header */
+struct pfcphdr {
+	u8	flags;
+	u8	message_type;
+	__be16	message_length;
+};
+
+/* PFCP header flags */
+#define PFCP_SEID_FLAG		BIT(0)
+#define PFCP_MP_FLAG		BIT(1)
+
+#define PFCP_VERSION_MASK	GENMASK(4, 0)
+
+#define PFCP_HLEN (sizeof(struct udphdr) + sizeof(struct pfcphdr))
+
+/* PFCP node related messages */
+struct pfcphdr_node {
+	u8	seq_number[3];
+	u8	reserved;
+};
+
+/* PFCP session related messages */
+struct pfcphdr_session {
+	__be64	seid;
+	u8	seq_number[3];
+#ifdef __LITTLE_ENDIAN_BITFIELD
+	u8	message_priority:4,
+		reserved:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	u8	reserved:4,
+		message_priority:4;
+#else
+#error "Please fix <asm/byteorder>"
+#endif
+};
+
+struct pfcp_metadata {
+	u8 type;
+	__be64 seid;
+} __packed;
+
+enum {
+	PFCP_TYPE_NODE		= 0,
+	PFCP_TYPE_SESSION	= 1,
+};
+
+#define PFCP_HEADROOM (sizeof(struct iphdr) + sizeof(struct udphdr) + \
+		       sizeof(struct pfcphdr) + sizeof(struct ethhdr))
+#define PFCP6_HEADROOM (sizeof(struct ipv6hdr) + sizeof(struct udphdr) + \
+			sizeof(struct pfcphdr) + sizeof(struct ethhdr))
+
+static inline struct pfcphdr *pfcp_hdr(struct sk_buff *skb)
+{
+	return (struct pfcphdr *)(udp_hdr(skb) + 1);
+}
+
+static inline struct pfcphdr_node *pfcp_hdr_node(struct sk_buff *skb)
+{
+	return (struct pfcphdr_node *)(pfcp_hdr(skb) + 1);
+}
+
+static inline struct pfcphdr_session *pfcp_hdr_session(struct sk_buff *skb)
+{
+	return (struct pfcphdr_session *)(pfcp_hdr(skb) + 1);
+}
+
+static inline bool netif_is_pfcp(const struct net_device *dev)
+{
+	return dev->rtnl_link_ops &&
+	       !strcmp(dev->rtnl_link_ops->kind, "pfcp");
+}
+
+#endif