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, 132 insertions, 0 deletions

diff --git a/include/net/garp.h b/include/net/garp.h
new file mode 100644
index 000000000..59a07b171
--- /dev/null
+++ b/include/net/garp.h
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_GARP_H
+#define _NET_GARP_H
+
+#include <linux/if_ether.h>
+#include <linux/types.h>
+#include <net/stp.h>
+
+#define GARP_PROTOCOL_ID	0x1
+#define GARP_END_MARK		0x0
+
+struct garp_pdu_hdr {
+	__be16	protocol;
+};
+
+struct garp_msg_hdr {
+	u8	attrtype;
+};
+
+enum garp_attr_event {
+	GARP_LEAVE_ALL,
+	GARP_JOIN_EMPTY,
+	GARP_JOIN_IN,
+	GARP_LEAVE_EMPTY,
+	GARP_LEAVE_IN,
+	GARP_EMPTY,
+};
+
+struct garp_attr_hdr {
+	u8	len;
+	u8	event;
+	u8	data[];
+};
+
+struct garp_skb_cb {
+	u8	cur_type;
+};
+
+static inline struct garp_skb_cb *garp_cb(struct sk_buff *skb)
+{
+	BUILD_BUG_ON(sizeof(struct garp_skb_cb) >
+		     sizeof_field(struct sk_buff, cb));
+	return (struct garp_skb_cb *)skb->cb;
+}
+
+enum garp_applicant_state {
+	GARP_APPLICANT_INVALID,
+	GARP_APPLICANT_VA,
+	GARP_APPLICANT_AA,
+	GARP_APPLICANT_QA,
+	GARP_APPLICANT_LA,
+	GARP_APPLICANT_VP,
+	GARP_APPLICANT_AP,
+	GARP_APPLICANT_QP,
+	GARP_APPLICANT_VO,
+	GARP_APPLICANT_AO,
+	GARP_APPLICANT_QO,
+	__GARP_APPLICANT_MAX
+};
+#define GARP_APPLICANT_MAX	(__GARP_APPLICANT_MAX - 1)
+
+enum garp_event {
+	GARP_EVENT_REQ_JOIN,
+	GARP_EVENT_REQ_LEAVE,
+	GARP_EVENT_R_JOIN_IN,
+	GARP_EVENT_R_JOIN_EMPTY,
+	GARP_EVENT_R_EMPTY,
+	GARP_EVENT_R_LEAVE_IN,
+	GARP_EVENT_R_LEAVE_EMPTY,
+	GARP_EVENT_TRANSMIT_PDU,
+	__GARP_EVENT_MAX
+};
+#define GARP_EVENT_MAX		(__GARP_EVENT_MAX - 1)
+
+enum garp_action {
+	GARP_ACTION_NONE,
+	GARP_ACTION_S_JOIN_IN,
+	GARP_ACTION_S_LEAVE_EMPTY,
+};
+
+struct garp_attr {
+	struct rb_node			node;
+	enum garp_applicant_state	state;
+	u8				type;
+	u8				dlen;
+	unsigned char			data[];
+};
+
+enum garp_applications {
+	GARP_APPLICATION_GVRP,
+	__GARP_APPLICATION_MAX
+};
+#define GARP_APPLICATION_MAX	(__GARP_APPLICATION_MAX - 1)
+
+struct garp_application {
+	enum garp_applications	type;
+	unsigned int		maxattr;
+	struct stp_proto	proto;
+};
+
+struct garp_applicant {
+	struct garp_application	*app;
+	struct net_device	*dev;
+	struct timer_list	join_timer;
+
+	spinlock_t		lock;
+	struct sk_buff_head	queue;
+	struct sk_buff		*pdu;
+	struct rb_root		gid;
+	struct rcu_head		rcu;
+};
+
+struct garp_port {
+	struct garp_applicant __rcu	*applicants[GARP_APPLICATION_MAX + 1];
+	struct rcu_head			rcu;
+};
+
+int garp_register_application(struct garp_application *app);
+void garp_unregister_application(struct garp_application *app);
+
+int garp_init_applicant(struct net_device *dev, struct garp_application *app);
+void garp_uninit_applicant(struct net_device *dev,
+			   struct garp_application *app);
+
+int garp_request_join(const struct net_device *dev,
+		      const struct garp_application *app, const void *data,
+		      u8 len, u8 type);
+void garp_request_leave(const struct net_device *dev,
+			const struct garp_application *app,
+			const void *data, u8 len, u8 type);
+
+#endif /* _NET_GARP_H */