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, 49 insertions, 0 deletions

diff --git a/include/crypto/chacha20poly1305.h b/include/crypto/chacha20poly1305.h
new file mode 100644
index 000000000..0f6d99170
--- /dev/null
+++ b/include/crypto/chacha20poly1305.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef __CHACHA20POLY1305_H
+#define __CHACHA20POLY1305_H
+
+#include <linux/types.h>
+#include <linux/scatterlist.h>
+
+enum chacha20poly1305_lengths {
+	XCHACHA20POLY1305_NONCE_SIZE = 24,
+	CHACHA20POLY1305_KEY_SIZE = 32,
+	CHACHA20POLY1305_AUTHTAG_SIZE = 16
+};
+
+void chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
+			      const u8 *ad, const size_t ad_len,
+			      const u64 nonce,
+			      const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
+
+bool __must_check
+chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
+			 const u8 *ad, const size_t ad_len, const u64 nonce,
+			 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
+
+void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
+			       const u8 *ad, const size_t ad_len,
+			       const u8 nonce[at_least XCHACHA20POLY1305_NONCE_SIZE],
+			       const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
+
+bool __must_check xchacha20poly1305_decrypt(
+	u8 *dst, const u8 *src, const size_t src_len,
+	const u8 *ad, const size_t ad_len,
+	const u8 nonce[at_least XCHACHA20POLY1305_NONCE_SIZE],
+	const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
+
+bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
+					 const u8 *ad, const size_t ad_len,
+					 const u64 nonce,
+					 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
+
+bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
+					 const u8 *ad, const size_t ad_len,
+					 const u64 nonce,
+					 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
+
+#endif /* __CHACHA20POLY1305_H */