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, 51 insertions, 0 deletions

diff --git a/include/drm/intel/pick.h b/include/drm/intel/pick.h
new file mode 100644
index 000000000..d976fab8f
--- /dev/null
+++ b/include/drm/intel/pick.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2026 Intel Corporation */
+
+#ifndef _PICK_H_
+#define _PICK_H_
+
+/*
+ * Given the first two numbers __a and __b of arbitrarily many evenly spaced
+ * numbers, pick the 0-based __index'th value.
+ *
+ * Always prefer this over _PICK() if the numbers are evenly spaced.
+ */
+#define _PICK_EVEN(__index, __a, __b) ((__a) + (__index) * ((__b) - (__a)))
+
+/*
+ * Like _PICK_EVEN(), but supports 2 ranges of evenly spaced address offsets.
+ * @__c_index corresponds to the index in which the second range starts to be
+ * used. Using math interval notation, the first range is used for indexes [ 0,
+ * @__c_index), while the second range is used for [ @__c_index, ... ). Example:
+ *
+ * #define _FOO_A			0xf000
+ * #define _FOO_B			0xf004
+ * #define _FOO_C			0xf008
+ * #define _SUPER_FOO_A			0xa000
+ * #define _SUPER_FOO_B			0xa100
+ * #define FOO(x)			_MMIO(_PICK_EVEN_2RANGES(x, 3,		\
+ *					      _FOO_A, _FOO_B,			\
+ *					      _SUPER_FOO_A, _SUPER_FOO_B))
+ *
+ * This expands to:
+ *	0: 0xf000,
+ *	1: 0xf004,
+ *	2: 0xf008,
+ *	3: 0xa000,
+ *	4: 0xa100,
+ *	5: 0xa200,
+ *	...
+ */
+#define _PICK_EVEN_2RANGES(__index, __c_index, __a, __b, __c, __d)		\
+	(BUILD_BUG_ON_ZERO(!__is_constexpr(__c_index)) +			\
+	 ((__index) < (__c_index) ? _PICK_EVEN(__index, __a, __b) :		\
+				   _PICK_EVEN((__index) - (__c_index), __c, __d)))
+
+/*
+ * Given the arbitrary numbers in varargs, pick the 0-based __index'th number.
+ *
+ * Always prefer _PICK_EVEN() over this if the numbers are evenly spaced.
+ */
+#define _PICK(__index, ...) (((const u32 []){ __VA_ARGS__ })[__index])
+
+#endif