From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Fri, 14 Aug 2026 15:43:51 -0700
Subject: 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
 HEAD

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.
---
 net/batman-adv/bitarray.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 net/batman-adv/bitarray.c

(limited to 'net/batman-adv/bitarray.c')

diff --git a/net/batman-adv/bitarray.c b/net/batman-adv/bitarray.c
new file mode 100644
index 000000000..67cb35633
--- /dev/null
+++ b/net/batman-adv/bitarray.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Simon Wunderlich, Marek Lindner
+ */
+
+#include "bitarray.h"
+#include "main.h"
+
+#include <linux/bitmap.h>
+
+#include "log.h"
+
+/* shift the packet array by n places. */
+static void batadv_bitmap_shift_left(unsigned long *seq_bits, s32 n)
+{
+	if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
+		return;
+
+	bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE);
+}
+
+/**
+ * batadv_bit_get_packet() - receive and process one packet within the sequence
+ *  number window
+ * @priv: the bat priv with all the mesh interface information
+ * @seq_bits: pointer to the sequence number bitmap of received packets
+ * @seq_num_diff: difference between the current/received sequence number and
+ *  the last sequence number
+ * @set_mark: whether this packet should be marked in seq_bits
+ *
+ * Return: true if the window was moved (either new or very old),
+ *  false if the window was not moved/shifted.
+ */
+bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
+			   s32 seq_num_diff, int set_mark)
+{
+	struct batadv_priv *bat_priv = priv;
+
+	/* sequence number is slightly older. We already got a sequence number
+	 * higher than this one, so we just mark it.
+	 */
+	if (seq_num_diff <= 0 && seq_num_diff > -BATADV_TQ_LOCAL_WINDOW_SIZE) {
+		if (set_mark)
+			batadv_set_bit(seq_bits, -seq_num_diff);
+		return false;
+	}
+
+	/* sequence number is slightly newer, so we shift the window and
+	 * set the mark if required
+	 */
+	if (seq_num_diff > 0 && seq_num_diff < BATADV_TQ_LOCAL_WINDOW_SIZE) {
+		batadv_bitmap_shift_left(seq_bits, seq_num_diff);
+
+		if (set_mark)
+			batadv_set_bit(seq_bits, 0);
+		return true;
+	}
+
+	/* sequence number is much newer, probably missed a lot of packets */
+	if (seq_num_diff >= BATADV_TQ_LOCAL_WINDOW_SIZE &&
+	    seq_num_diff < BATADV_EXPECTED_SEQNO_RANGE) {
+		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+			   "We missed a lot of packets (%i) !\n",
+			   seq_num_diff - 1);
+		bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
+		if (set_mark)
+			batadv_set_bit(seq_bits, 0);
+		return true;
+	}
+
+	/* received a much older packet. The other host either restarted
+	 * or the old packet got delayed somewhere in the network. The
+	 * packet should be dropped without calling this function if the
+	 * seqno window is protected.
+	 *
+	 * seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE
+	 * or
+	 * seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE
+	 */
+	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+		   "Other host probably restarted!\n");
+
+	bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
+	if (set_mark)
+		batadv_set_bit(seq_bits, 0);
+
+	return true;
+}
-- 
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